mirror of https://gitee.com/openkylin/linux.git
813 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Mel Gorman
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675becce15 |
mm: vmscan: do not throttle based on pfmemalloc reserves if node has no ZONE_NORMAL
throttle_direct_reclaim() is meant to trigger during swap-over-network during which the min watermark is treated as a pfmemalloc reserve. It throttes on the first node in the zonelist but this is flawed. The user-visible impact is that a process running on CPU whose local memory node has no ZONE_NORMAL will stall for prolonged periods of time, possibly indefintely. This is due to throttle_direct_reclaim thinking the pfmemalloc reserves are depleted when in fact they don't exist on that node. On a NUMA machine running a 32-bit kernel (I know) allocation requests from CPUs on node 1 would detect no pfmemalloc reserves and the process gets throttled. This patch adjusts throttling of direct reclaim to throttle based on the first node in the zonelist that has a usable ZONE_NORMAL or lower zone. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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bfc8c90139 |
mem-hotplug: implement get/put_online_mems
kmem_cache_{create,destroy,shrink} need to get a stable value of
cpu/node online mask, because they init/destroy/access per-cpu/node
kmem_cache parts, which can be allocated or destroyed on cpu/mem
hotplug. To protect against cpu hotplug, these functions use
{get,put}_online_cpus. However, they do nothing to synchronize with
memory hotplug - taking the slab_mutex does not eliminate the
possibility of race as described in patch 2.
What we need there is something like get_online_cpus, but for memory.
We already have lock_memory_hotplug, which serves for the purpose, but
it's a bit of a hammer right now, because it's backed by a mutex. As a
result, it imposes some limitations to locking order, which are not
desirable, and can't be used just like get_online_cpus. That's why in
patch 1 I substitute it with get/put_online_mems, which work exactly
like get/put_online_cpus except they block not cpu, but memory hotplug.
[ v1 can be found at https://lkml.org/lkml/2014/4/6/68. I NAK'ed it by
myself, because it used an rw semaphore for get/put_online_mems,
making them dead lock prune. ]
This patch (of 2):
{un}lock_memory_hotplug, which is used to synchronize against memory
hotplug, is currently backed by a mutex, which makes it a bit of a
hammer - threads that only want to get a stable value of online nodes
mask won't be able to proceed concurrently. Also, it imposes some
strong locking ordering rules on it, which narrows down the set of its
usage scenarios.
This patch introduces get/put_online_mems, which are the same as
get/put_online_cpus, but for memory hotplug, i.e. executing a code
inside a get/put_online_mems section will guarantee a stable value of
online nodes, present pages, etc.
lock_memory_hotplug()/unlock_memory_hotplug() are removed altogether.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Tang Chen <tangchen@cn.fujitsu.com>
Cc: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: Toshi Kani <toshi.kani@hp.com>
Cc: Xishi Qiu <qiuxishi@huawei.com>
Cc: Jiang Liu <liuj97@gmail.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Suleiman Souhlal
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6f04f48dc9 |
mm: only force scan in reclaim when none of the LRUs are big enough.
Prior to this change, we would decide whether to force scan a LRU during
reclaim if that LRU itself was too small for the current priority.
However, this can lead to the file LRU getting force scanned even if
there are a lot of anonymous pages we can reclaim, leading to hot file
pages getting needlessly reclaimed.
To address this, we instead only force scan when none of the reclaimable
LRUs are big enough.
Gives huge improvements with zswap. For example, when doing -j20 kernel
build in a 500MB container with zswap enabled, runtime (in seconds) is
greatly reduced:
x without this change
+ with this change
N Min Max Median Avg Stddev
x 5 700.997 790.076 763.928 754.05 39.59493
+ 5 141.634 197.899 155.706 161.9 21.270224
Difference at 95.0% confidence
-592.15 +/- 46.3521
-78.5293% +/- 6.14709%
(Student's t, pooled s = 31.7819)
Should also give some improvements in regular (non-zswap) swap cases.
Yes, hughd found significant speedup using regular swap, with several
memcgs under pressure; and it should also be effective in the non-memcg
case, whenever one or another zone LRU is forced too small.
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Rafael Aquini <aquini@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Luigi Semenzato <semenzato@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Al Viro
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8174202b34 |
write_iter variants of {__,}generic_file_aio_write()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Johannes Weiner
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623762517e |
revert "mm: vmscan: do not swap anon pages just because free+file is low"
This reverts commit
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Christoph Lameter
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83da751005 |
vmscan: reclaim_clean_pages_from_list() must use mod_zone_page_state()
Seems to be called with preemption enabled. Therefore it must use mod_zone_page_state instead. Signed-off-by: Christoph Lameter <cl@linux.com> Reported-by: Grygorii Strashko <grygorii.strashko@ti.com> Tested-by: Grygorii Strashko <grygorii.strashko@ti.com> Cc: Tejun Heo <tj@kernel.org> Cc: Santosh Shilimkar <santosh.shilimkar@ti.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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0bf1457f0c |
mm: vmscan: do not swap anon pages just because free+file is low
Page reclaim force-scans / swaps anonymous pages when file cache drops
below the high watermark of a zone in order to prevent what little cache
remains from thrashing.
However, on bigger machines the high watermark value can be quite large
and when the workload is dominated by a static anonymous/shmem set, the
file set might just be a small window of used-once cache. In such
situations, the VM starts swapping heavily when instead it should be
recycling the no longer used cache.
This is a longer-standing problem, but it's more likely to trigger after
commit
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Weijie Yang
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9bbc04eeb0 |
mm/vmscan: do not check compaction_ready on promoted zones
We abort direct reclaim if we find the zone is ready for compaction. Sometimes the zone is just a promoted highmem zone to force a scan of highmem, which is not the intended zone the caller want to allocate a page from. In this situation, setting aborted_reclaim to indicate the caller turned back to retry the allocation is waste of time and could cause a loop in __alloc_pages_slowpath(). This patch does not check compaction_ready() on promoted zones to avoid the above situation. Only set aborted_reclaim if the caller intended zone is ready for compaction. Signed-off-by: Weijie Yang <weijie.yang@samsung.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Weijie Yang
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619d0d76c1 |
mm/vmscan: restore sc->gfp_mask after promoting it to __GFP_HIGHMEM
We promote sc->gfp_mask to __GFP_HIGHMEM to forcibly scan highmem if
there are too many buffer_heads pinning highmem. See
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Johannes Weiner
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a528910e12 |
mm: thrash detection-based file cache sizing
The VM maintains cached filesystem pages on two types of lists. One list holds the pages recently faulted into the cache, the other list holds pages that have been referenced repeatedly on that first list. The idea is to prefer reclaiming young pages over those that have shown to benefit from caching in the past. We call the recently usedbut ultimately was not significantly better than a FIFO policy and still thrashed cache based on eviction speed, rather than actual demand for cache. This patch solves one half of the problem by decoupling the ability to detect working set changes from the inactive list size. By maintaining a history of recently evicted file pages it can detect frequently used pages with an arbitrarily small inactive list size, and subsequently apply pressure on the active list based on actual demand for cache, not just overall eviction speed. Every zone maintains a counter that tracks inactive list aging speed. When a page is evicted, a snapshot of this counter is stored in the now-empty page cache radix tree slot. On refault, the minimum access distance of the page can be assessed, to evaluate whether the page should be part of the active list or not. This fixes the VM's blindness towards working set changes in excess of the inactive list. And it's the foundation to further improve the protection ability and reduce the minimum inactive list size of 50%. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Bob Liu <bob.liu@oracle.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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91b0abe36a |
mm + fs: store shadow entries in page cache
Reclaim will be leaving shadow entries in the page cache radix tree upon evicting the real page. As those pages are found from the LRU, an iput() can lead to the inode being freed concurrently. At this point, reclaim must no longer install shadow pages because the inode freeing code needs to ensure the page tree is really empty. Add an address_space flag, AS_EXITING, that the inode freeing code sets under the tree lock before doing the final truncate. Reclaim will check for this flag before installing shadow pages. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jan Kara <jack@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Luigi Semenzato <semenzato@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Metin Doslu <metin@citusdata.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ozgun Erdogan <ozgun@citusdata.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Ryan Mallon <rmallon@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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d5bc5fd3fc |
mm: vmscan: shrink_slab: rename max_pass -> freeable
The name `max_pass' is misleading, because this variable actually keeps the estimate number of freeable objects, not the maximal number of objects we can scan in this pass, which can be twice that. Rename it to reflect its actual meaning. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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3115cd9145 |
mm: vmscan: remove shrink_control arg from do_try_to_free_pages()
There is no need passing on a shrink_control struct from try_to_free_pages() and friends to do_try_to_free_pages() and then to shrink_zones(), because it is only used in shrink_zones() and the only field initialized on the top level is gfp_mask, which is always equal to scan_control.gfp_mask. So let's move shrink_control initialization to shrink_zones(). Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Dave Chinner <dchinner@redhat.com> Cc: Glauber Costa <glommer@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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65ec02cb9a |
mm: vmscan: move call to shrink_slab() to shrink_zones()
This reduces the indentation level of do_try_to_free_pages() and removes extra loop over all eligible zones counting the number of on-LRU pages. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reviewed-by: Glauber Costa <glommer@gmail.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Dave Chinner <dchinner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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99120b772b |
mm: vmscan: respect NUMA policy mask when shrinking slab on direct reclaim
When direct reclaim is executed by a process bound to a set of NUMA nodes, we should scan only those nodes when possible, but currently we will scan kmem from all online nodes even if the kmem shrinker is NUMA aware. That said, binding a process to a particular NUMA node won't prevent it from shrinking inode/dentry caches from other nodes, which is not good. Fix this. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Dave Chinner <dchinner@redhat.com> Cc: Glauber Costa <glommer@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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a1c3bfb2f6 |
mm/page-writeback.c: do not count anon pages as dirtyable memory
The VM is currently heavily tuned to avoid swapping. Whether that is good or bad is a separate discussion, but as long as the VM won't swap to make room for dirty cache, we can not consider anonymous pages when calculating the amount of dirtyable memory, the baseline to which dirty_background_ratio and dirty_ratio are applied. A simple workload that occupies a significant size (40+%, depending on memory layout, storage speeds etc.) of memory with anon/tmpfs pages and uses the remainder for a streaming writer demonstrates this problem. In that case, the actual cache pages are a small fraction of what is considered dirtyable overall, which results in an relatively large portion of the cache pages to be dirtied. As kswapd starts rotating these, random tasks enter direct reclaim and stall on IO. Only consider free pages and file pages dirtyable. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Tejun Heo <tj@kernel.org> Tested-by: Tejun Heo <tj@kernel.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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ec97097bca |
mm: vmscan: call NUMA-unaware shrinkers irrespective of nodemask
If a shrinker is not NUMA-aware, shrink_slab() should call it exactly once with nid=0, but currently it is not true: if node 0 is not set in the nodemask or if it is not online, we will not call such shrinkers at all. As a result some slabs will be left untouched under some circumstances. Let us fix it. Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Reported-by: Dave Chinner <dchinner@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Glauber Costa <glommer@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
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0b1fb40a3b |
mm: vmscan: shrink all slab objects if tight on memory
When reclaiming kmem, we currently don't scan slabs that have less than
batch_size objects (see shrink_slab_node()):
while (total_scan >= batch_size) {
shrinkctl->nr_to_scan = batch_size;
shrinker->scan_objects(shrinker, shrinkctl);
total_scan -= batch_size;
}
If there are only a few shrinkers available, such a behavior won't cause
any problems, because the batch_size is usually small, but if we have a
lot of slab shrinkers, which is perfectly possible since FS shrinkers
are now per-superblock, we can end up with hundreds of megabytes of
practically unreclaimable kmem objects. For instance, mounting a
thousand of ext2 FS images with a hundred of files in each and iterating
over all the files using du(1) will result in about 200 Mb of FS caches
that cannot be dropped even with the aid of the vm.drop_caches sysctl!
This problem was initially pointed out by Glauber Costa [*]. Glauber
proposed to fix it by making the shrink_slab() always take at least one
pass, to put it simply, turning the scan loop above to a do{}while()
loop. However, this proposal was rejected, because it could result in
more aggressive and frequent slab shrinking even under low memory
pressure when total_scan is naturally very small.
This patch is a slightly modified version of Glauber's approach.
Similarly to Glauber's patch, it makes shrink_slab() scan less than
batch_size objects, but only if the total number of objects we want to
scan (total_scan) is greater than the total number of objects available
(max_pass). Since total_scan is biased as half max_pass if the current
delta change is small:
if (delta < max_pass / 4)
total_scan = min(total_scan, max_pass / 2);
this is only possible if we are scanning at high prio. That said, this
patch shouldn't change the vmscan behaviour if the memory pressure is
low, but if we are tight on memory, we will do our best by trying to
reclaim all available objects, which sounds reasonable.
[*] http://www.spinics.net/lists/cgroups/msg06913.html
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Glauber Costa <glommer@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Sasha Levin
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309381feae |
mm: dump page when hitting a VM_BUG_ON using VM_BUG_ON_PAGE
Most of the VM_BUG_ON assertions are performed on a page. Usually, when one of these assertions fails we'll get a BUG_ON with a call stack and the registers. I've recently noticed based on the requests to add a small piece of code that dumps the page to various VM_BUG_ON sites that the page dump is quite useful to people debugging issues in mm. This patch adds a VM_BUG_ON_PAGE(cond, page) which beyond doing what VM_BUG_ON() does, also dumps the page before executing the actual BUG_ON. [akpm@linux-foundation.org: fix up includes] Signed-off-by: Sasha Levin <sasha.levin@oracle.com> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andrew Vagin
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ae39332162 |
mm/vmscan.c: don't forget to free shrinker->nr_deferred
This leak was added by commit
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Rafael Aquini
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117aad1e9e |
mm: avoid reinserting isolated balloon pages into LRU lists
Isolated balloon pages can wrongly end up in LRU lists when migrate_pages() finishes its round without draining all the isolated page list. The same issue can happen when reclaim_clean_pages_from_list() tries to reclaim pages from an isolated page list, before migration, in the CMA path. Such balloon page leak opens a race window against LRU lists shrinkers that leads us to the following kernel panic: BUG: unable to handle kernel NULL pointer dereference at 0000000000000028 IP: [<ffffffff810c2625>] shrink_page_list+0x24e/0x897 PGD 3cda2067 PUD 3d713067 PMD 0 Oops: 0000 [#1] SMP CPU: 0 PID: 340 Comm: kswapd0 Not tainted 3.12.0-rc1-22626-g4367597 #87 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 RIP: shrink_page_list+0x24e/0x897 RSP: 0000:ffff88003da499b8 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff88003e82bd60 RCX: 00000000000657d5 RDX: 0000000000000000 RSI: 000000000000031f RDI: ffff88003e82bd40 RBP: ffff88003da49ab0 R08: 0000000000000001 R09: 0000000081121a45 R10: ffffffff81121a45 R11: ffff88003c4a9a28 R12: ffff88003e82bd40 R13: ffff88003da0e800 R14: 0000000000000001 R15: ffff88003da49d58 FS: 0000000000000000(0000) GS:ffff88003fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000067d9000 CR3: 000000003ace5000 CR4: 00000000000407b0 Call Trace: shrink_inactive_list+0x240/0x3de shrink_lruvec+0x3e0/0x566 __shrink_zone+0x94/0x178 shrink_zone+0x3a/0x82 balance_pgdat+0x32a/0x4c2 kswapd+0x2f0/0x372 kthread+0xa2/0xaa ret_from_fork+0x7c/0xb0 Code: 80 7d 8f 01 48 83 95 68 ff ff ff 00 4c 89 e7 e8 5a 7b 00 00 48 85 c0 49 89 c5 75 08 80 7d 8f 00 74 3e eb 31 48 8b 80 18 01 00 00 <48> 8b 74 0d 48 8b 78 30 be 02 00 00 00 ff d2 eb RIP [<ffffffff810c2625>] shrink_page_list+0x24e/0x897 RSP <ffff88003da499b8> CR2: 0000000000000028 ---[ end trace 703d2451af6ffbfd ]--- Kernel panic - not syncing: Fatal exception This patch fixes the issue, by assuring the proper tests are made at putback_movable_pages() & reclaim_clean_pages_from_list() to avoid isolated balloon pages being wrongly reinserted in LRU lists. [akpm@linux-foundation.org: clarify awkward comment text] Signed-off-by: Rafael Aquini <aquini@redhat.com> Reported-by: Luiz Capitulino <lcapitulino@redhat.com> Tested-by: Luiz Capitulino <lcapitulino@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andrew Morton
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0608f43da6 |
revert "memcg, vmscan: integrate soft reclaim tighter with zone shrinking code"
Revert commit
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Andrew Morton
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b1aff7fcf8 |
revert "vmscan, memcg: do softlimit reclaim also for targeted reclaim"
Revert commit
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Andrew Morton
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694fbc0fe7 |
revert "memcg: enhance memcg iterator to support predicates"
Revert commit
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Andrew Morton
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3120055e86 |
revert "memcg, vmscan: do not attempt soft limit reclaim if it would not scan anything"
Revert commit
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Andrew Morton
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20ba27f52e |
revert "memcg, vmscan: do not fall into reclaim-all pass too quickly"
Revert commit
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Linus Torvalds
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ac4de9543a |
Merge branch 'akpm' (patches from Andrew Morton)
Merge more patches from Andrew Morton: "The rest of MM. Plus one misc cleanup" * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (35 commits) mm/Kconfig: add MMU dependency for MIGRATION. kernel: replace strict_strto*() with kstrto*() mm, thp: count thp_fault_fallback anytime thp fault fails thp: consolidate code between handle_mm_fault() and do_huge_pmd_anonymous_page() thp: do_huge_pmd_anonymous_page() cleanup thp: move maybe_pmd_mkwrite() out of mk_huge_pmd() mm: cleanup add_to_page_cache_locked() thp: account anon transparent huge pages into NR_ANON_PAGES truncate: drop 'oldsize' truncate_pagecache() parameter mm: make lru_add_drain_all() selective memcg: document cgroup dirty/writeback memory statistics memcg: add per cgroup writeback pages accounting memcg: check for proper lock held in mem_cgroup_update_page_stat memcg: remove MEMCG_NR_FILE_MAPPED memcg: reduce function dereference memcg: avoid overflow caused by PAGE_ALIGN memcg: rename RESOURCE_MAX to RES_COUNTER_MAX memcg: correct RESOURCE_MAX to ULLONG_MAX mm: memcg: do not trap chargers with full callstack on OOM mm: memcg: rework and document OOM waiting and wakeup ... |
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Andrew Morton
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f894ffa865 |
memcg: trivial cleanups
Clean up some mess made by the "Soft limit rework" series, and a few other things. Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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e975de998b |
memcg, vmscan: do not fall into reclaim-all pass too quickly
shrink_zone starts with soft reclaim pass first and then falls back to regular reclaim if nothing has been scanned. This behavior is natural but there is a catch. Memcg iterators, when used with the reclaim cookie, are designed to help to prevent from over reclaim by interleaving reclaimers (per node-zone-priority) so the tree walk might miss many (even all) nodes in the hierarchy e.g. when there are direct reclaimers racing with each other or with kswapd in the global case or multiple allocators reaching the limit for the target reclaim case. To make it even more complicated, targeted reclaim doesn't do the whole tree walk because it stops reclaiming once it reclaims sufficient pages. As a result groups over the limit might be missed, thus nothing is scanned, and reclaim would fall back to the reclaim all mode. This patch checks for the incomplete tree walk in shrink_zone. If no group has been visited and the hierarchy is soft reclaimable then we must have missed some groups, in which case the __shrink_zone is called again. This doesn't guarantee there will be some progress of course because the current reclaimer might be still racing with others but it would at least give a chance to start the walk without a big risk of reclaim latencies. Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@openvz.org> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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e839b6a1c8 |
memcg, vmscan: do not attempt soft limit reclaim if it would not scan anything
mem_cgroup_should_soft_reclaim controls whether soft reclaim pass is done and it always says yes currently. Memcg iterators are clever to skip nodes that are not soft reclaimable quite efficiently but mem_cgroup_should_soft_reclaim can be more clever and do not start the soft reclaim pass at all if it knows that nothing would be scanned anyway. In order to do that, simply reuse mem_cgroup_soft_reclaim_eligible for the target group of the reclaim and allow the pass only if the whole subtree wouldn't be skipped. Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@openvz.org> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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de57780dc6 |
memcg: enhance memcg iterator to support predicates
The caller of the iterator might know that some nodes or even subtrees should be skipped but there is no way to tell iterators about that so the only choice left is to let iterators to visit each node and do the selection outside of the iterating code. This, however, doesn't scale well with hierarchies with many groups where only few groups are interesting. This patch adds mem_cgroup_iter_cond variant of the iterator with a callback which gets called for every visited node. There are three possible ways how the callback can influence the walk. Either the node is visited, it is skipped but the tree walk continues down the tree or the whole subtree of the current group is skipped. [hughd@google.com: fix memcg-less page reclaim] Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@openvz.org> Cc: Greg Thelen <gthelen@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Ying Han <yinghan@google.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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a5b7c87f92 |
vmscan, memcg: do softlimit reclaim also for targeted reclaim
Soft reclaim has been done only for the global reclaim (both background and direct). Since "memcg: integrate soft reclaim tighter with zone shrinking code" there is no reason for this limitation anymore as the soft limit reclaim doesn't use any special code paths and it is a part of the zone shrinking code which is used by both global and targeted reclaims. From the semantic point of view it is natural to consider soft limit before touching all groups in the hierarchy tree which is touching the hard limit because soft limit tells us where to push back when there is a memory pressure. It is not important whether the pressure comes from the limit or imbalanced zones. This patch simply enables soft reclaim unconditionally in mem_cgroup_should_soft_reclaim so it is enabled for both global and targeted reclaim paths. mem_cgroup_soft_reclaim_eligible needs to learn about the root of the reclaim to know where to stop checking soft limit state of parents up the hierarchy. Say we have A (over soft limit) \ B (below s.l., hit the hard limit) / \ C D (below s.l.) B is the source of the outside memory pressure now for D but we shouldn't soft reclaim it because it is behaving well under B subtree and we can still reclaim from C (pressumably it is over the limit). mem_cgroup_soft_reclaim_eligible should therefore stop climbing up the hierarchy at B (root of the memory pressure). Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Glauber Costa <glommer@openvz.org> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Michel Lespinasse <walken@google.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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3b38722efd |
memcg, vmscan: integrate soft reclaim tighter with zone shrinking code
This patchset is sitting out of tree for quite some time without any objections. I would be really happy if it made it into 3.12. I do not want to push it too hard but I think this work is basically ready and waiting more doesn't help. The basic idea is quite simple. Pull soft reclaim into shrink_zone in the first step and get rid of the previous soft reclaim infrastructure. shrink_zone is done in two passes now. First it tries to do the soft limit reclaim and it falls back to reclaim-all mode if no group is over the limit or no pages have been scanned. The second pass happens at the same priority so the only time we waste is the memcg tree walk which has been updated in the third step to have only negligible overhead. As a bonus we will get rid of a _lot_ of code by this and soft reclaim will not stand out like before when it wasn't integrated into the zone shrinking code and it reclaimed at priority 0 (the testing results show that some workloads suffers from such an aggressive reclaim). The clean up is in a separate patch because I felt it would be easier to review that way. The second step is soft limit reclaim integration into targeted reclaim. It should be rather straight forward. Soft limit has been used only for the global reclaim so far but it makes sense for any kind of pressure coming from up-the-hierarchy, including targeted reclaim. The third step (patches 4-8) addresses the tree walk overhead by enhancing memcg iterators to enable skipping whole subtrees and tracking number of over soft limit children at each level of the hierarchy. This information is updated same way the old soft limit tree was updated (from memcg_check_events) so we shouldn't see an additional overhead. In fact mem_cgroup_update_soft_limit is much simpler than tree manipulation done previously. __shrink_zone uses mem_cgroup_soft_reclaim_eligible as a predicate for mem_cgroup_iter so the decision whether a particular group should be visited is done at the iterator level which allows us to decide to skip the whole subtree as well (if there is no child in excess). This reduces the tree walk overhead considerably. * TEST 1 ======== My primary test case was a parallel kernel build with 2 groups (make is running with -j8 with a distribution .config in a separate cgroup without any hard limit) on a 32 CPU machine booted with 1GB memory and both builds run taskset to Node 0 cpus. I was mostly interested in 2 setups. Default - no soft limit set and - and 0 soft limit set to both groups. The first one should tell us whether the rework regresses the default behavior while the second one should show us improvements in an extreme case where both workloads are always over the soft limit. /usr/bin/time -v has been used to collect the statistics and each configuration had 3 runs after fresh boot without any other load on the system. base is mmotm-2013-07-18-16-40 rework all 8 patches applied on top of base * No-limit User no-limit/base: min: 651.92 max: 672.65 avg: 664.33 std: 8.01 runs: 6 no-limit/rework: min: 657.34 [100.8%] max: 668.39 [99.4%] avg: 663.13 [99.8%] std: 3.61 runs: 6 System no-limit/base: min: 69.33 max: 71.39 avg: 70.32 std: 0.79 runs: 6 no-limit/rework: min: 69.12 [99.7%] max: 71.05 [99.5%] avg: 70.04 [99.6%] std: 0.59 runs: 6 Elapsed no-limit/base: min: 398.27 max: 422.36 avg: 408.85 std: 7.74 runs: 6 no-limit/rework: min: 386.36 [97.0%] max: 438.40 [103.8%] avg: 416.34 [101.8%] std: 18.85 runs: 6 The results are within noise. Elapsed time has a bigger variance but the average looks good. * 0-limit User 0-limit/base: min: 573.76 max: 605.63 avg: 585.73 std: 12.21 runs: 6 0-limit/rework: min: 645.77 [112.6%] max: 666.25 [110.0%] avg: 656.97 [112.2%] std: 7.77 runs: 6 System 0-limit/base: min: 69.57 max: 71.13 avg: 70.29 std: 0.54 runs: 6 0-limit/rework: min: 68.68 [98.7%] max: 71.40 [100.4%] avg: 69.91 [99.5%] std: 0.87 runs: 6 Elapsed 0-limit/base: min: 1306.14 max: 1550.17 avg: 1430.35 std: 90.86 runs: 6 0-limit/rework: min: 404.06 [30.9%] max: 465.94 [30.1%] avg: 434.81 [30.4%] std: 22.68 runs: 6 The improvement is really huge here (even bigger than with my previous testing and I suspect that this highly depends on the storage). Page fault statistics tell us at least part of the story: Minor 0-limit/base: min: 37180461.00 max: 37319986.00 avg: 37247470.00 std: 54772.71 runs: 6 0-limit/rework: min: 36751685.00 [98.8%] max: 36805379.00 [98.6%] avg: 36774506.33 [98.7%] std: 17109.03 runs: 6 Major 0-limit/base: min: 170604.00 max: 221141.00 avg: 196081.83 std: 18217.01 runs: 6 0-limit/rework: min: 2864.00 [1.7%] max: 10029.00 [4.5%] avg: 5627.33 [2.9%] std: 2252.71 runs: 6 Same as with my previous testing Minor faults are more or less within noise but Major fault count is way bellow the base kernel. While this looks as a nice win it is fair to say that 0-limit configuration is quite artificial. So I was playing with 0-no-limit loads as well. * TEST 2 ======== The following results are from 2 groups configuration on a 16GB machine (single NUMA node). - A running stream IO (dd if=/dev/zero of=local.file bs=1024) with 2*TotalMem with 0 soft limit. - B running a mem_eater which consumes TotalMem-1G without any limit. The mem_eater consumes the memory in 100 chunks with 1s nap after each mmap+poppulate so that both loads have chance to fight for the memory. The expected result is that B shouldn't be reclaimed and A shouldn't see a big dropdown in elapsed time. User base: min: 2.68 max: 2.89 avg: 2.76 std: 0.09 runs: 3 rework: min: 3.27 [122.0%] max: 3.74 [129.4%] avg: 3.44 [124.6%] std: 0.21 runs: 3 System base: min: 86.26 max: 88.29 avg: 87.28 std: 0.83 runs: 3 rework: min: 81.05 [94.0%] max: 84.96 [96.2%] avg: 83.14 [95.3%] std: 1.61 runs: 3 Elapsed base: min: 317.28 max: 332.39 avg: 325.84 std: 6.33 runs: 3 rework: min: 281.53 [88.7%] max: 298.16 [89.7%] avg: 290.99 [89.3%] std: 6.98 runs: 3 System time improved slightly as well as Elapsed. My previous testing has shown worse numbers but this again seem to depend on the storage speed. My theory is that the writeback doesn't catch up and prio-0 soft reclaim falls into wait on writeback page too often in the base kernel. The patched kernel doesn't do that because the soft reclaim is done from the kswapd/direct reclaim context. This can be seen on the following graph nicely. The A's group usage_in_bytes regurarly drops really low very often. All 3 runs http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/stream.png resp. a detail of the single run http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/stream-one-run.png mem_eater seems to be doing better as well. It gets to the full allocation size faster as can be seen on the following graph: http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/mem_eater-one-run.png /proc/meminfo collected during the test also shows that rework kernel hasn't swapped that much (well almost not at all): base: max: 123900 K avg: 56388.29 K rework: max: 300 K avg: 128.68 K kswapd and direct reclaim statistics are of no use unfortunatelly because soft reclaim is not accounted properly as the counters are hidden by global_reclaim() checks in the base kernel. * TEST 3 ======== Another test was the same configuration as TEST2 except the stream IO was replaced by a single kbuild (16 parallel jobs bound to Node0 cpus same as in TEST1) and mem_eater allocated TotalMem-200M so kbuild had only 200MB left. Kbuild did better with the rework kernel here as well: User base: min: 860.28 max: 872.86 avg: 868.03 std: 5.54 runs: 3 rework: min: 880.81 [102.4%] max: 887.45 [101.7%] avg: 883.56 [101.8%] std: 2.83 runs: 3 System base: min: 84.35 max: 85.06 avg: 84.79 std: 0.31 runs: 3 rework: min: 85.62 [101.5%] max: 86.09 [101.2%] avg: 85.79 [101.2%] std: 0.21 runs: 3 Elapsed base: min: 135.36 max: 243.30 avg: 182.47 std: 45.12 runs: 3 rework: min: 110.46 [81.6%] max: 116.20 [47.8%] avg: 114.15 [62.6%] std: 2.61 runs: 3 Minor base: min: 36635476.00 max: 36673365.00 avg: 36654812.00 std: 15478.03 runs: 3 rework: min: 36639301.00 [100.0%] max: 36695541.00 [100.1%] avg: 36665511.00 [100.0%] std: 23118.23 runs: 3 Major base: min: 14708.00 max: 53328.00 avg: 31379.00 std: 16202.24 runs: 3 rework: min: 302.00 [2.1%] max: 414.00 [0.8%] avg: 366.33 [1.2%] std: 47.22 runs: 3 Again we can see a significant improvement in Elapsed (it also seems to be more stable), there is a huge dropdown for the Major page faults and much more swapping: base: max: 583736 K avg: 112547.43 K rework: max: 4012 K avg: 124.36 K Graphs from all three runs show the variability of the kbuild quite nicely. It even seems that it took longer after every run with the base kernel which would be quite surprising as the source tree for the build is removed and caches are dropped after each run so the build operates on a freshly extracted sources everytime. http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/kbuild-mem_eater.png My other testing shows that this is just a matter of timing and other runs behave differently the std for Elapsed time is similar ~50. Example of other three runs: http://labs.suse.cz/mhocko/soft_limit_rework/stream_io-vs-mem_eater/kbuild-mem_eater2.png So to wrap this up. The series is still doing good and improves the soft limit. The testing results for bunch of cgroups with both stream IO and kbuild loads can be found in "memcg: track children in soft limit excess to improve soft limit". This patch: Memcg soft reclaim has been traditionally triggered from the global reclaim paths before calling shrink_zone. mem_cgroup_soft_limit_reclaim then picked up a group which exceeds the soft limit the most and reclaimed it with 0 priority to reclaim at least SWAP_CLUSTER_MAX pages. The infrastructure requires per-node-zone trees which hold over-limit groups and keep them up-to-date (via memcg_check_events) which is not cost free. Although this overhead hasn't turned out to be a bottle neck the implementation is suboptimal because mem_cgroup_update_tree has no idea which zones consumed memory over the limit so we could easily end up having a group on a node-zone tree having only few pages from that node-zone. This patch doesn't try to fix node-zone trees management because it seems that integrating soft reclaim into zone shrinking sounds much easier and more appropriate for several reasons. First of all 0 priority reclaim was a crude hack which might lead to big stalls if the group's LRUs are big and hard to reclaim (e.g. a lot of dirty/writeback pages). Soft reclaim should be applicable also to the targeted reclaim which is awkward right now without additional hacks. Last but not least the whole infrastructure eats quite some code. After this patch shrink_zone is done in 2 passes. First it tries to do the soft reclaim if appropriate (only for global reclaim for now to keep compatible with the original state) and fall back to ignoring soft limit if no group is eligible to soft reclaim or nothing has been scanned during the first pass. Only groups which are over their soft limit or any of their parents up the hierarchy is over the limit are considered eligible during the first pass. Soft limit tree which is not necessary anymore will be removed in the follow up patch to make this patch smaller and easier to review. Signed-off-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Glauber Costa <glommer@openvz.org> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Ying Han <yinghan@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Glauber Costa <glommer@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
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26935fb06e |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs pile 4 from Al Viro: "list_lru pile, mostly" This came out of Andrew's pile, Al ended up doing the merge work so that Andrew didn't have to. Additionally, a few fixes. * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (42 commits) super: fix for destroy lrus list_lru: dynamically adjust node arrays shrinker: Kill old ->shrink API. shrinker: convert remaining shrinkers to count/scan API staging/lustre/libcfs: cleanup linux-mem.h staging/lustre/ptlrpc: convert to new shrinker API staging/lustre/obdclass: convert lu_object shrinker to count/scan API staging/lustre/ldlm: convert to shrinkers to count/scan API hugepage: convert huge zero page shrinker to new shrinker API i915: bail out earlier when shrinker cannot acquire mutex drivers: convert shrinkers to new count/scan API fs: convert fs shrinkers to new scan/count API xfs: fix dquot isolation hang xfs-convert-dquot-cache-lru-to-list_lru-fix xfs: convert dquot cache lru to list_lru xfs: rework buffer dispose list tracking xfs-convert-buftarg-lru-to-generic-code-fix xfs: convert buftarg LRU to generic code fs: convert inode and dentry shrinking to be node aware vmscan: per-node deferred work ... |
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Lisa Du
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6e543d5780 |
mm: vmscan: fix do_try_to_free_pages() livelock
This patch is based on KOSAKI's work and I add a little more description, please refer https://lkml.org/lkml/2012/6/14/74. Currently, I found system can enter a state that there are lots of free pages in a zone but only order-0 and order-1 pages which means the zone is heavily fragmented, then high order allocation could make direct reclaim path's long stall(ex, 60 seconds) especially in no swap and no compaciton enviroment. This problem happened on v3.4, but it seems issue still lives in current tree, the reason is do_try_to_free_pages enter live lock: kswapd will go to sleep if the zones have been fully scanned and are still not balanced. As kswapd thinks there's little point trying all over again to avoid infinite loop. Instead it changes order from high-order to 0-order because kswapd think order-0 is the most important. Look at |
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Vlastimil Babka
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0ec3b74c7f |
mm: putback_lru_page: remove unnecessary call to page_lru_base_type()
The goal of this patch series is to improve performance of munlock() of
large mlocked memory areas on systems without THP. This is motivated by
reported very long times of crash recovery of processes with such areas,
where munlock() can take several seconds. See
http://lwn.net/Articles/548108/
The work was driven by a simple benchmark (to be included in mmtests) that
mmaps() e.g. 56GB with MAP_LOCKED | MAP_POPULATE and measures the time of
munlock(). Profiling was performed by attaching operf --pid to the
process and sending a signal to trigger the munlock() part and then notify
bach the monitoring wrapper to stop operf, so that only munlock() appears
in the profile.
The profiles have shown that CPU time is spent mostly by atomic operations
and repeated locking per single pages. This series aims to reduce both, starting
from simpler to more complex changes.
Patch 1 performs a simple cleanup in putback_lru_page() so that page lru base
type is not determined without being actually needed.
Patch 2 removes an unnecessary call to lru_add_drain() which drains the per-cpu
pagevec after each munlocked page is put there.
Patch 3 changes munlock_vma_range() to use an on-stack pagevec for isolating
multiple non-THP pages under a single lru_lock instead of locking and
processing each page separately.
Patch 4 changes the NR_MLOCK accounting to be called only once per the pvec
introduced by previous patch.
Patch 5 uses the introduced pagevec to batch also the work of putback_lru_page
when possible, bypassing the per-cpu pvec and associated overhead.
Patch 6 removes a redundant get_page/put_page pair which saves costly atomic
operations.
Patch 7 avoids calling follow_page_mask() on each individual page, and obtains
multiple page references under a single page table lock where possible.
Measurements were made using 3.11-rc3 as a baseline. The first set of
measurements shows the possibly ideal conditions where batching should
help the most. All memory is allocated from a single NUMA node and THP is
disabled.
timedmunlock
3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3
0 1 2 3 4 5 6 7
Elapsed min 3.38 ( 0.00%) 3.39 ( -0.13%) 3.00 ( 11.33%) 2.70 ( 20.20%) 2.67 ( 21.11%) 2.37 ( 29.88%) 2.20 ( 34.91%) 1.91 ( 43.59%)
Elapsed mean 3.39 ( 0.00%) 3.40 ( -0.23%) 3.01 ( 11.33%) 2.70 ( 20.26%) 2.67 ( 21.21%) 2.38 ( 29.88%) 2.21 ( 34.93%) 1.92 ( 43.46%)
Elapsed stddev 0.01 ( 0.00%) 0.01 (-43.09%) 0.01 ( 15.42%) 0.01 ( 23.42%) 0.00 ( 89.78%) 0.01 ( -7.15%) 0.00 ( 76.69%) 0.02 (-91.77%)
Elapsed max 3.41 ( 0.00%) 3.43 ( -0.52%) 3.03 ( 11.29%) 2.72 ( 20.16%) 2.67 ( 21.63%) 2.40 ( 29.50%) 2.21 ( 35.21%) 1.96 ( 42.39%)
Elapsed range 0.03 ( 0.00%) 0.04 (-51.16%) 0.02 ( 6.27%) 0.02 ( 14.67%) 0.00 ( 88.90%) 0.03 (-19.18%) 0.01 ( 73.70%) 0.06 (-113.35%
The second set of measurements simulates the worst possible conditions for
batching by using numactl --interleave, so that there is in fact only one
page per pagevec. Even in this case the series seems to improve
performance thanks to reduced atomic operations and removal of
lru_add_drain().
timedmunlock
3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3
0 1 2 3 4 5 6 7
Elapsed min 4.00 ( 0.00%) 4.04 ( -0.93%) 3.87 ( 3.37%) 3.72 ( 6.94%) 3.81 ( 4.72%) 3.69 ( 7.82%) 3.64 ( 8.92%) 3.41 ( 14.81%)
Elapsed mean 4.17 ( 0.00%) 4.15 ( 0.51%) 4.03 ( 3.49%) 3.89 ( 6.84%) 3.86 ( 7.48%) 3.89 ( 6.69%) 3.70 ( 11.27%) 3.48 ( 16.59%)
Elapsed stddev 0.16 ( 0.00%) 0.08 ( 50.76%) 0.10 ( 41.58%) 0.16 ( 4.59%) 0.05 ( 72.38%) 0.19 (-12.91%) 0.05 ( 68.09%) 0.06 ( 66.03%)
Elapsed max 4.34 ( 0.00%) 4.32 ( 0.56%) 4.19 ( 3.62%) 4.12 ( 5.15%) 3.91 ( 9.88%) 4.12 ( 5.25%) 3.80 ( 12.58%) 3.56 ( 18.08%)
Elapsed range 0.34 ( 0.00%) 0.28 ( 17.91%) 0.32 ( 6.45%) 0.40 (-15.73%) 0.10 ( 70.06%) 0.43 (-24.84%) 0.15 ( 55.32%) 0.15 ( 56.16%)
For completeness, a third set of measurements shows the situation where
THP is enabled and allocations are again done on a single NUMA node. Here
munlock() is already very fast thanks to huge pages, and this series does
not compromise that performance. It seems that the removal of call to
lru_add_drain() still helps a bit.
timedmunlock
3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3 3.11-rc3
0 1 2 3 4 5 6 7
Elapsed min 0.01 ( 0.00%) 0.01 ( -0.11%) 0.01 ( 6.59%) 0.01 ( 5.41%) 0.01 ( 5.45%) 0.01 ( 5.03%) 0.01 ( 6.08%) 0.01 ( 5.20%)
Elapsed mean 0.01 ( 0.00%) 0.01 ( -0.27%) 0.01 ( 6.39%) 0.01 ( 5.30%) 0.01 ( 5.32%) 0.01 ( 5.03%) 0.01 ( 5.97%) 0.01 ( 5.22%)
Elapsed stddev 0.00 ( 0.00%) 0.00 ( -9.59%) 0.00 ( 10.77%) 0.00 ( 3.24%) 0.00 ( 24.42%) 0.00 ( 31.86%) 0.00 ( -7.46%) 0.00 ( 6.11%)
Elapsed max 0.01 ( 0.00%) 0.01 ( -0.01%) 0.01 ( 6.83%) 0.01 ( 5.42%) 0.01 ( 5.79%) 0.01 ( 5.53%) 0.01 ( 6.08%) 0.01 ( 5.26%)
Elapsed range 0.00 ( 0.00%) 0.00 ( 7.30%) 0.00 ( 24.38%) 0.00 ( 6.10%) 0.00 ( 30.79%) 0.00 ( 42.52%) 0.00 ( 6.11%) 0.00 ( 10.07%)
This patch (of 7):
In putback_lru_page() since commit
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Johannes Weiner
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892f795df1 |
mm: vmscan: fix numa reclaim balance problem in kswapd
The way the page allocator interacts with kswapd creates aging imbalances, where the amount of time a userspace page gets in memory under reclaim pressure is dependent on which zone, which node the allocator took the page frame from. #1 fixes missed kswapd wakeups on NUMA systems, which lead to some nodes falling behind for a full reclaim cycle relative to the other nodes in the system #3 fixes an interaction where kswapd and a continuous stream of page allocations keep the preferred zone of a task between the high and low watermark (allocations succeed + kswapd does not go to sleep) indefinitely, completely underutilizing the lower zones and thrashing on the preferred zone These patches are the aging fairness part of the thrash-detection based file LRU balancing. Andrea recommended to submit them separately as they are bugfixes in their own right. The following test ran a foreground workload (memcachetest) with background IO of various sizes on a 4 node 8G system (similar results were observed with single-node 4G systems): parallelio BAS FAIRALLO BASE FAIRALLOC Ops memcachetest-0M 5170.00 ( 0.00%) 5283.00 ( 2.19%) Ops memcachetest-791M 4740.00 ( 0.00%) 5293.00 ( 11.67%) Ops memcachetest-2639M 2551.00 ( 0.00%) 4950.00 ( 94.04%) Ops memcachetest-4487M 2606.00 ( 0.00%) 3922.00 ( 50.50%) Ops io-duration-0M 0.00 ( 0.00%) 0.00 ( 0.00%) Ops io-duration-791M 55.00 ( 0.00%) 18.00 ( 67.27%) Ops io-duration-2639M 235.00 ( 0.00%) 103.00 ( 56.17%) Ops io-duration-4487M 278.00 ( 0.00%) 173.00 ( 37.77%) Ops swaptotal-0M 0.00 ( 0.00%) 0.00 ( 0.00%) Ops swaptotal-791M 245184.00 ( 0.00%) 0.00 ( 0.00%) Ops swaptotal-2639M 468069.00 ( 0.00%) 108778.00 ( 76.76%) Ops swaptotal-4487M 452529.00 ( 0.00%) 76623.00 ( 83.07%) Ops swapin-0M 0.00 ( 0.00%) 0.00 ( 0.00%) Ops swapin-791M 108297.00 ( 0.00%) 0.00 ( 0.00%) Ops swapin-2639M 169537.00 ( 0.00%) 50031.00 ( 70.49%) Ops swapin-4487M 167435.00 ( 0.00%) 34178.00 ( 79.59%) Ops minorfaults-0M 1518666.00 ( 0.00%) 1503993.00 ( 0.97%) Ops minorfaults-791M 1676963.00 ( 0.00%) 1520115.00 ( 9.35%) Ops minorfaults-2639M 1606035.00 ( 0.00%) 1799717.00 (-12.06%) Ops minorfaults-4487M 1612118.00 ( 0.00%) 1583825.00 ( 1.76%) Ops majorfaults-0M 6.00 ( 0.00%) 0.00 ( 0.00%) Ops majorfaults-791M 13836.00 ( 0.00%) 10.00 ( 99.93%) Ops majorfaults-2639M 22307.00 ( 0.00%) 6490.00 ( 70.91%) Ops majorfaults-4487M 21631.00 ( 0.00%) 4380.00 ( 79.75%) BAS FAIRALLO BASE FAIRALLOC User 287.78 460.97 System 2151.67 3142.51 Elapsed 9737.00 8879.34 BAS FAIRALLO BASE FAIRALLOC Minor Faults 53721925 57188551 Major Faults 392195 15157 Swap Ins 2994854 112770 Swap Outs 4907092 134982 Direct pages scanned 0 41824 Kswapd pages scanned 32975063 8128269 Kswapd pages reclaimed 6323069 7093495 Direct pages reclaimed 0 41824 Kswapd efficiency 19% 87% Kswapd velocity 3386.573 915.414 Direct efficiency 100% 100% Direct velocity 0.000 4.710 Percentage direct scans 0% 0% Zone normal velocity 2011.338 550.661 Zone dma32 velocity 1365.623 369.221 Zone dma velocity 9.612 0.242 Page writes by reclaim 18732404.000 614807.000 Page writes file 13825312 479825 Page writes anon 4907092 134982 Page reclaim immediate 85490 5647 Sector Reads 12080532 483244 Sector Writes 88740508 65438876 Page rescued immediate 0 0 Slabs scanned 82560 12160 Direct inode steals 0 0 Kswapd inode steals 24401 40013 Kswapd skipped wait 0 0 THP fault alloc 6 8 THP collapse alloc 5481 5812 THP splits 75 22 THP fault fallback 0 0 THP collapse fail 0 0 Compaction stalls 0 54 Compaction success 0 45 Compaction failures 0 9 Page migrate success 881492 82278 Page migrate failure 0 0 Compaction pages isolated 0 60334 Compaction migrate scanned 0 53505 Compaction free scanned 0 1537605 Compaction cost 914 86 NUMA PTE updates 46738231 41988419 NUMA hint faults 31175564 24213387 NUMA hint local faults 10427393 6411593 NUMA pages migrated 881492 55344 AutoNUMA cost 156221 121361 The overall runtime was reduced, throughput for both the foreground workload as well as the background IO improved, major faults, swapping and reclaim activity shrunk significantly, reclaim efficiency more than quadrupled. This patch: When the page allocator fails to get a page from all zones in its given zonelist, it wakes up the per-node kswapds for all zones that are at their low watermark. However, with a system under load the free pages in a zone can fluctuate enough that the allocation fails but the kswapd wakeup is also skipped while the zone is still really close to the low watermark. When one node misses a wakeup like this, it won't be aged before all the other node's zones are down to their low watermarks again. And skipping a full aging cycle is an obvious fairness problem. Kswapd runs until the high watermarks are restored, so it should also be woken when the high watermarks are not met. This ages nodes more equally and creates a safety margin for the page counter fluctuation. By using zone_balanced(), it will now check, in addition to the watermark, if compaction requires more order-0 pages to create a higher order page. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Paul Bolle <paul.bollee@gmail.com> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Dave Chinner
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a0b02131c5 |
shrinker: Kill old ->shrink API.
There are no more users of this API, so kill it dead, dead, dead and quietly bury the corpse in a shallow, unmarked grave in a dark forest deep in the hills... [glommer@openvz.org: added flowers to the grave] Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Reviewed-by: Greg Thelen <gthelen@google.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Glauber Costa
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1d3d4437ea |
vmscan: per-node deferred work
The list_lru infrastructure already keeps per-node LRU lists in its node-specific list_lru_node arrays and provide us with a per-node API, and the shrinkers are properly equiped with node information. This means that we can now focus our shrinking effort in a single node, but the work that is deferred from one run to another is kept global at nr_in_batch. Work can be deferred, for instance, during direct reclaim under a GFP_NOFS allocation, where situation, all the filesystem shrinkers will be prevented from running and accumulate in nr_in_batch the amount of work they should have done, but could not. This creates an impedance problem, where upon node pressure, work deferred will accumulate and end up being flushed in other nodes. The problem we describe is particularly harmful in big machines, where many nodes can accumulate at the same time, all adding to the global counter nr_in_batch. As we accumulate more and more, we start to ask for the caches to flush even bigger numbers. The result is that the caches are depleted and do not stabilize. To achieve stable steady state behavior, we need to tackle it differently. In this patch we keep the deferred count per-node, in the new array nr_deferred[] (the name is also a bit more descriptive) and will never accumulate that to other nodes. Signed-off-by: Glauber Costa <glommer@openvz.org> Cc: Dave Chinner <dchinner@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Dave Chinner
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0ce3d74450 |
shrinker: add node awareness
Pass the node of the current zone being reclaimed to shrink_slab(), allowing the shrinker control nodemask to be set appropriately for node aware shrinkers. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@openvz.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Dave Chinner
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24f7c6b981 |
mm: new shrinker API
The current shrinker callout API uses an a single shrinker call for multiple functions. To determine the function, a special magical value is passed in a parameter to change the behaviour. This complicates the implementation and return value specification for the different behaviours. Separate the two different behaviours into separate operations, one to return a count of freeable objects in the cache, and another to scan a certain number of objects in the cache for freeing. In defining these new operations, ensure the return values and resultant behaviours are clearly defined and documented. Modify shrink_slab() to use the new API and implement the callouts for all the existing shrinkers. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Glauber Costa <glommer@parallels.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Artem Bityutskiy <artem.bityutskiy@linux.intel.com> Cc: Arve Hjønnevåg <arve@android.com> Cc: Carlos Maiolino <cmaiolino@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Chuck Lever <chuck.lever@oracle.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: David Rientjes <rientjes@google.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: J. Bruce Fields <bfields@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Stultz <john.stultz@linaro.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Kent Overstreet <koverstreet@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: Thomas Hellstrom <thellstrom@vmware.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Mel Gorman
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918fc718c5 |
mm: vmscan: do not scale writeback pages when deciding whether to set ZONE_WRITEBACK
After the patch "mm: vmscan: Flatten kswapd priority loop" was merged the scanning priority of kswapd changed. The priority now rises until it is scanning enough pages to meet the high watermark. shrink_inactive_list sets ZONE_WRITEBACK if a number of pages were encountered under writeback but this value is scaled based on the priority. As kswapd frequently scans with a higher priority now it is relatively easy to set ZONE_WRITEBACK. This patch removes the scaling and treates writeback pages similar to how it treats unqueued dirty pages and congested pages. The user-visible effect should be that kswapd will writeback fewer pages from reclaim context. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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5a1c9cbc15 |
mm: vmscan: do not continue scanning if reclaim was aborted for compaction
Direct reclaim is not aborting to allow compaction to go ahead properly. do_try_to_free_pages is told to abort reclaim which is happily ignores and instead increases priority instead until it reaches 0 and starts shrinking file/anon equally. This patch corrects the situation by aborting reclaim when requested instead of raising priority. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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c53954a092 |
mm: remove lru parameter from __lru_cache_add and lru_cache_add_lru
Similar to __pagevec_lru_add, this patch removes the LRU parameter from __lru_cache_add and lru_cache_add_lru as the caller does not control the exact LRU the page gets added to. lru_cache_add_lru gets renamed to lru_cache_add the name is silly without the lru parameter. With the parameter removed, it is required that the caller indicate if they want the page added to the active or inactive list by setting or clearing PageActive respectively. [akpm@linux-foundation.org: Suggested the patch] [gang.chen@asianux.com: fix used-unintialized warning] Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Chen Gang <gang.chen@asianux.com> Cc: Jan Kara <jack@suse.cz> Cc: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Alexey Lyahkov <alexey.lyashkov@gmail.com> Cc: Andrew Perepechko <anserper@ya.ru> Cc: Robin Dong <sanbai@taobao.com> Cc: Theodore Tso <tytso@mit.edu> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Bernd Schubert <bernd.schubert@fastmail.fm> Cc: David Howells <dhowells@redhat.com> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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b45972265f |
mm: vmscan: take page buffers dirty and locked state into account
Page reclaim keeps track of dirty and under writeback pages and uses it to determine if wait_iff_congested() should stall or if kswapd should begin writing back pages. This fails to account for buffer pages that can be under writeback but not PageWriteback which is the case for filesystems like ext3 ordered mode. Furthermore, PageDirty buffer pages can have all the buffers clean and writepage does no IO so it should not be accounted as congested. This patch adds an address_space operation that filesystems may optionally use to check if a page is really dirty or really under writeback. An implementation is provided for for buffer_heads is added and used for block operations and ext3 in ordered mode. By default the page flags are obeyed. Credit goes to Jan Kara for identifying that the page flags alone are not sufficient for ext3 and sanity checking a number of ideas on how the problem could be addressed. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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d04e8acd03 |
mm: vmscan: treat pages marked for immediate reclaim as zone congestion
Currently a zone will only be marked congested if the underlying BDI is congested but if dirty pages are spread across zones it is possible that an individual zone is full of dirty pages without being congested. The impact is that zone gets scanned very quickly potentially reclaiming really clean pages. This patch treats pages marked for immediate reclaim as congested for the purposes of marking a zone ZONE_CONGESTED and stalling in wait_iff_congested. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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8e95028280 |
mm: vmscan: move direct reclaim wait_iff_congested into shrink_list
shrink_inactive_list makes decisions on whether to stall based on the number of dirty pages encountered. The wait_iff_congested() call in shrink_page_list does no such thing and it's arbitrary. This patch moves the decision on whether to set ZONE_CONGESTED and the wait_iff_congested call into shrink_page_list. This keeps all the decisions on whether to stall or not in the one place. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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f7ab8db791 |
mm: vmscan: set zone flags before blocking
In shrink_page_list a decision may be made to stall and flag a zone as ZONE_WRITEBACK so that if a large number of unqueued dirty pages are encountered later then the reclaimer will stall. Set ZONE_WRITEBACK before potentially going to sleep so it is noticed sooner. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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b1a6f21e3b |
mm: vmscan: stall page reclaim after a list of pages have been processed
Commit "mm: vmscan: Block kswapd if it is encountering pages under writeback" blocks page reclaim if it encounters pages under writeback marked for immediate reclaim. It blocks while pages are still isolated from the LRU which is unnecessary. This patch defers the blocking until after the isolated pages have been processed and tidies up some of the comments. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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e2be15f6c3 |
mm: vmscan: stall page reclaim and writeback pages based on dirty/writepage pages encountered
Further testing of the "Reduce system disruption due to kswapd"
discovered a few problems. First and foremost, it's possible for pages
under writeback to be freed which will lead to badness. Second, as
pages were not being swapped the file LRU was being scanned faster and
clean file pages were being reclaimed. In some cases this results in
increased read IO to re-read data from disk. Third, more pages were
being written from kswapd context which can adversly affect IO
performance. Lastly, it was observed that PageDirty pages are not
necessarily dirty on all filesystems (buffers can be clean while
PageDirty is set and ->writepage generates no IO) and not all
filesystems set PageWriteback when the page is being written (e.g.
ext3). This disconnect confuses the reclaim stalling logic. This
follow-up series is aimed at these problems.
The tests were based on three kernels
vanilla: kernel 3.9 as that is what the current mmotm uses as a baseline
mmotm-20130522 is mmotm as of 22nd May with "Reduce system disruption due to
kswapd" applied on top as per what should be in Andrew's tree
right now
lessdisrupt-v7r10 is this follow-up series on top of the mmotm kernel
The first test used memcached+memcachetest while some background IO was
in progress as implemented by the parallel IO tests implement in MM
Tests. memcachetest benchmarks how many operations/second memcached can
service. It starts with no background IO on a freshly created ext4
filesystem and then re-runs the test with larger amounts of IO in the
background to roughly simulate a large copy in progress. The
expectation is that the IO should have little or no impact on
memcachetest which is running entirely in memory.
parallelio
3.9.0 3.9.0 3.9.0
vanilla mm1-mmotm-20130522 mm1-lessdisrupt-v7r10
Ops memcachetest-0M 23117.00 ( 0.00%) 22780.00 ( -1.46%) 22763.00 ( -1.53%)
Ops memcachetest-715M 23774.00 ( 0.00%) 23299.00 ( -2.00%) 22934.00 ( -3.53%)
Ops memcachetest-2385M 4208.00 ( 0.00%) 24154.00 (474.00%) 23765.00 (464.76%)
Ops memcachetest-4055M 4104.00 ( 0.00%) 25130.00 (512.33%) 24614.00 (499.76%)
Ops io-duration-0M 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops io-duration-715M 12.00 ( 0.00%) 7.00 ( 41.67%) 6.00 ( 50.00%)
Ops io-duration-2385M 116.00 ( 0.00%) 21.00 ( 81.90%) 21.00 ( 81.90%)
Ops io-duration-4055M 160.00 ( 0.00%) 36.00 ( 77.50%) 35.00 ( 78.12%)
Ops swaptotal-0M 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swaptotal-715M 140138.00 ( 0.00%) 18.00 ( 99.99%) 18.00 ( 99.99%)
Ops swaptotal-2385M 385682.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swaptotal-4055M 418029.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-0M 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-715M 144.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-2385M 134227.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-4055M 125618.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops minorfaults-0M 1536429.00 ( 0.00%) 1531632.00 ( 0.31%) 1533541.00 ( 0.19%)
Ops minorfaults-715M 1786996.00 ( 0.00%) 1612148.00 ( 9.78%) 1608832.00 ( 9.97%)
Ops minorfaults-2385M 1757952.00 ( 0.00%) 1614874.00 ( 8.14%) 1613541.00 ( 8.21%)
Ops minorfaults-4055M 1774460.00 ( 0.00%) 1633400.00 ( 7.95%) 1630881.00 ( 8.09%)
Ops majorfaults-0M 1.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops majorfaults-715M 184.00 ( 0.00%) 167.00 ( 9.24%) 166.00 ( 9.78%)
Ops majorfaults-2385M 24444.00 ( 0.00%) 155.00 ( 99.37%) 93.00 ( 99.62%)
Ops majorfaults-4055M 21357.00 ( 0.00%) 147.00 ( 99.31%) 134.00 ( 99.37%)
memcachetest is the transactions/second reported by memcachetest. In
the vanilla kernel note that performance drops from around
23K/sec to just over 4K/second when there is 2385M of IO going
on in the background. With current mmotm, there is no collapse
in performance and with this follow-up series there is little
change.
swaptotal is the total amount of swap traffic. With mmotm and the follow-up
series, the total amount of swapping is much reduced.
3.9.0 3.9.0 3.9.0
vanillamm1-mmotm-20130522mm1-lessdisrupt-v7r10
Minor Faults 11160152 10706748 10622316
Major Faults 46305 755 678
Swap Ins 260249 0 0
Swap Outs 683860 18 18
Direct pages scanned 0 678 2520
Kswapd pages scanned 6046108 8814900 1639279
Kswapd pages reclaimed 1081954
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Mel Gorman
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7c954f6de6 |
mm: vmscan: move logic from balance_pgdat() to kswapd_shrink_zone()
balance_pgdat() is very long and some of the logic can and should be internal to kswapd_shrink_zone(). Move it so the flow of balance_pgdat() is marginally easier to follow. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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b7ea3c417b |
mm: vmscan: check if kswapd should writepage once per pgdat scan
Currently kswapd checks if it should start writepage as it shrinks each zone without taking into consideration if the zone is balanced or not. This is not wrong as such but it does not make much sense either. This patch checks once per pgdat scan if kswapd should be writing pages. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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283aba9f9e |
mm: vmscan: block kswapd if it is encountering pages under writeback
Historically, kswapd used to congestion_wait() at higher priorities if
it was not making forward progress. This made no sense as the failure
to make progress could be completely independent of IO. It was later
replaced by wait_iff_congested() and removed entirely by commit
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Mel Gorman
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d43006d503 |
mm: vmscan: have kswapd writeback pages based on dirty pages encountered, not priority
Currently kswapd queues dirty pages for writeback if scanning at an elevated priority but the priority kswapd scans at is not related to the number of unqueued dirty encountered. Since commit "mm: vmscan: Flatten kswapd priority loop", the priority is related to the size of the LRU and the zone watermark which is no indication as to whether kswapd should write pages or not. This patch tracks if an excessive number of unqueued dirty pages are being encountered at the end of the LRU. If so, it indicates that dirty pages are being recycled before flusher threads can clean them and flags the zone so that kswapd will start writing pages until the zone is balanced. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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9aa41348a8 |
mm: vmscan: do not allow kswapd to scan at maximum priority
Page reclaim at priority 0 will scan the entire LRU as priority 0 is considered to be a near OOM condition. Kswapd can reach priority 0 quite easily if it is encountering a large number of pages it cannot reclaim such as pages under writeback. When this happens, kswapd reclaims very aggressively even though there may be no real risk of allocation failure or OOM. This patch prevents kswapd reaching priority 0 and trying to reclaim the world. Direct reclaimers will still reach priority 0 in the event of an OOM situation. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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2ab44f4345 |
mm: vmscan: decide whether to compact the pgdat based on reclaim progress
In the past, kswapd makes a decision on whether to compact memory after the pgdat was considered balanced. This more or less worked but it is late to make such a decision and does not fit well now that kswapd makes a decision whether to exit the zone scanning loop depending on reclaim progress. This patch will compact a pgdat if at least the requested number of pages were reclaimed from unbalanced zones for a given priority. If any zone is currently balanced, kswapd will not call compaction as it is expected the necessary pages are already available. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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b8e83b942a |
mm: vmscan: flatten kswapd priority loop
kswapd stops raising the scanning priority when at least SWAP_CLUSTER_MAX pages have been reclaimed or the pgdat is considered balanced. It then rechecks if it needs to restart at DEF_PRIORITY and whether high-order reclaim needs to be reset. This is not wrong per-se but it is confusing to follow and forcing kswapd to stay at DEF_PRIORITY may require several restarts before it has scanned enough pages to meet the high watermark even at 100% efficiency. This patch irons out the logic a bit by controlling when priority is raised and removing the "goto loop_again". This patch has kswapd raise the scanning priority until it is scanning enough pages that it could meet the high watermark in one shrink of the LRU lists if it is able to reclaim at 100% efficiency. It will not raise the scanning prioirty higher unless it is failing to reclaim any pages. To avoid infinite looping for high-order allocation requests kswapd will not reclaim for high-order allocations when it has reclaimed at least twice the number of pages as the allocation request. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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e82e0561da |
mm: vmscan: obey proportional scanning requirements for kswapd
Simplistically, the anon and file LRU lists are scanned proportionally depending on the value of vm.swappiness although there are other factors taken into account by get_scan_count(). The patch "mm: vmscan: Limit the number of pages kswapd reclaims" limits the number of pages kswapd reclaims but it breaks this proportional scanning and may evenly shrink anon/file LRUs regardless of vm.swappiness. This patch preserves the proportional scanning and reclaim. It does mean that kswapd will reclaim more than requested but the number of pages will be related to the high watermark. [mhocko@suse.cz: Correct proportional reclaim for memcg and simplify] [kamezawa.hiroyu@jp.fujitsu.com: Recalculate scan based on target] [hannes@cmpxchg.org: Account for already scanned pages properly] Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Tested-by: Zlatko Calusic <zcalusic@bitsync.net> Cc: dormando <dormando@rydia.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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75485363ce |
mm: vmscan: limit the number of pages kswapd reclaims at each priority
This series does not fix all the current known problems with reclaim but
it addresses one important swapping bug when there is background IO.
Changelog since V3
- Drop the slab shrink changes in light of Glaubers series and
discussions highlighted that there were a number of potential
problems with the patch. (mel)
- Rebased to 3.10-rc1
Changelog since V2
- Preserve ratio properly for proportional scanning (kamezawa)
Changelog since V1
- Rename ZONE_DIRTY to ZONE_TAIL_LRU_DIRTY (andi)
- Reformat comment in shrink_page_list (andi)
- Clarify some comments (dhillf)
- Rework how the proportional scanning is preserved
- Add PageReclaim check before kswapd starts writeback
- Reset sc.nr_reclaimed on every full zone scan
Kswapd and page reclaim behaviour has been screwy in one way or the
other for a long time. Very broadly speaking it worked in the far past
because machines were limited in memory so it did not have that many
pages to scan and it stalled congestion_wait() frequently to prevent it
going completely nuts. In recent times it has behaved very
unsatisfactorily with some of the problems compounded by the removal of
stall logic and the introduction of transparent hugepage support with
high-order reclaims.
There are many variations of bugs that are rooted in this area. One
example is reports of a large copy operations or backup causing the
machine to grind to a halt or applications pushed to swap. Sometimes in
low memory situations a large percentage of memory suddenly gets
reclaimed. In other cases an application starts and kswapd hits 100%
CPU usage for prolonged periods of time and so on. There is now talk of
introducing features like an extra free kbytes tunable to work around
aspects of the problem instead of trying to deal with it. It's
compounded by the problem that it can be very workload and machine
specific.
This series aims at addressing some of the worst of these problems
without attempting to fundmentally alter how page reclaim works.
Patches 1-2 limits the number of pages kswapd reclaims while still obeying
the anon/file proportion of the LRUs it should be scanning.
Patches 3-4 control how and when kswapd raises its scanning priority and
deletes the scanning restart logic which is tricky to follow.
Patch 5 notes that it is too easy for kswapd to reach priority 0 when
scanning and then reclaim the world. Down with that sort of thing.
Patch 6 notes that kswapd starts writeback based on scanning priority which
is not necessarily related to dirty pages. It will have kswapd
writeback pages if a number of unqueued dirty pages have been
recently encountered at the tail of the LRU.
Patch 7 notes that sometimes kswapd should stall waiting on IO to complete
to reduce LRU churn and the likelihood that it'll reclaim young
clean pages or push applications to swap. It will cause kswapd
to block on IO if it detects that pages being reclaimed under
writeback are recycling through the LRU before the IO completes.
Patchies 8-9 are cosmetic but balance_pgdat() is easier to follow after they
are applied.
This was tested using memcached+memcachetest while some background IO
was in progress as implemented by the parallel IO tests implement in MM
Tests.
memcachetest benchmarks how many operations/second memcached can service
and it is run multiple times. It starts with no background IO and then
re-runs the test with larger amounts of IO in the background to roughly
simulate a large copy in progress. The expectation is that the IO
should have little or no impact on memcachetest which is running
entirely in memory.
3.10.0-rc1 3.10.0-rc1
vanilla lessdisrupt-v4
Ops memcachetest-0M 22155.00 ( 0.00%) 22180.00 ( 0.11%)
Ops memcachetest-715M 22720.00 ( 0.00%) 22355.00 ( -1.61%)
Ops memcachetest-2385M 3939.00 ( 0.00%) 23450.00 (495.33%)
Ops memcachetest-4055M 3628.00 ( 0.00%) 24341.00 (570.92%)
Ops io-duration-0M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops io-duration-715M 12.00 ( 0.00%) 7.00 ( 41.67%)
Ops io-duration-2385M 118.00 ( 0.00%) 21.00 ( 82.20%)
Ops io-duration-4055M 162.00 ( 0.00%) 36.00 ( 77.78%)
Ops swaptotal-0M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swaptotal-715M 140134.00 ( 0.00%) 18.00 ( 99.99%)
Ops swaptotal-2385M 392438.00 ( 0.00%) 0.00 ( 0.00%)
Ops swaptotal-4055M 449037.00 ( 0.00%) 27864.00 ( 93.79%)
Ops swapin-0M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-715M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-2385M 148031.00 ( 0.00%) 0.00 ( 0.00%)
Ops swapin-4055M 135109.00 ( 0.00%) 0.00 ( 0.00%)
Ops minorfaults-0M 1529984.00 ( 0.00%) 1530235.00 ( -0.02%)
Ops minorfaults-715M 1794168.00 ( 0.00%) 1613750.00 ( 10.06%)
Ops minorfaults-2385M 1739813.00 ( 0.00%) 1609396.00 ( 7.50%)
Ops minorfaults-4055M 1754460.00 ( 0.00%) 1614810.00 ( 7.96%)
Ops majorfaults-0M 0.00 ( 0.00%) 0.00 ( 0.00%)
Ops majorfaults-715M 185.00 ( 0.00%) 180.00 ( 2.70%)
Ops majorfaults-2385M 24472.00 ( 0.00%) 101.00 ( 99.59%)
Ops majorfaults-4055M 22302.00 ( 0.00%) 229.00 ( 98.97%)
Note how the vanilla kernels performance collapses when there is enough
IO taking place in the background. This drop in performance is part of
what users complain of when they start backups. Note how the swapin and
major fault figures indicate that processes were being pushed to swap
prematurely. With the series applied, there is no noticable performance
drop and while there is still some swap activity, it's tiny.
20 iterations of this test were run in total and averaged. Every 5
iterations, additional IO was generated in the background using dd to
measure how the workload was impacted. The 0M, 715M, 2385M and 4055M
subblock refer to the amount of IO going on in the background at each
iteration. So memcachetest-2385M is reporting how many
transactions/second memcachetest recorded on average over 5 iterations
while there was 2385M of IO going on in the ground. There are six
blocks of information reported here
memcachetest is the transactions/second reported by memcachetest. In
the vanilla kernel note that performance drops from around
22K/sec to just under 4K/second when there is 2385M of IO going
on in the background. This is one type of performance collapse
users complain about if a large cp or backup starts in the
background
io-duration refers to how long it takes for the background IO to
complete. It's showing that with the patched kernel that the IO
completes faster while not interfering with the memcache
workload
swaptotal is the total amount of swap traffic. With the patched kernel,
the total amount of swapping is much reduced although it is
still not zero.
swapin in this case is an indication as to whether we are swap trashing.
The closer the swapin/swapout ratio is to 1, the worse the
trashing is. Note with the patched kernel that there is no swapin
activity indicating that all the pages swapped were really inactive
unused pages.
minorfaults are just minor faults. An increased number of minor faults
can indicate that page reclaim is unmapping the pages but not
swapping them out before they are faulted back in. With the
patched kernel, there is only a small change in minor faults
majorfaults are just major faults in the target workload and a high
number can indicate that a workload is being prematurely
swapped. With the patched kernel, major faults are much reduced. As
there are no swapin's recorded so it's not being swapped. The likely
explanation is that that libraries or configuration files used by
the workload during startup get paged out by the background IO.
Overall with the series applied, there is no noticable performance drop
due to background IO and while there is still some swap activity, it's
tiny and the lack of swapins imply that the swapped pages were inactive
and unused.
3.10.0-rc1 3.10.0-rc1
vanilla lessdisrupt-v4
Page Ins
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Shaohua Li
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5bc7b8aca9 |
mm: thp: add split tail pages to shrink page list in page reclaim
In page reclaim, huge page is split. split_huge_page() adds tail pages to LRU list. Since we are reclaiming a huge page, it's better we reclaim all subpages of the huge page instead of just the head page. This patch adds split tail pages to shrink page list so the tail pages can be reclaimed soon. Before this patch, run a swap workload: thp_fault_alloc 3492 thp_fault_fallback 608 thp_collapse_alloc 6 thp_collapse_alloc_failed 0 thp_split 916 With this patch: thp_fault_alloc 4085 thp_fault_fallback 16 thp_collapse_alloc 90 thp_collapse_alloc_failed 0 thp_split 1272 fallback allocation is reduced a lot. [akpm@linux-foundation.org: fix CONFIG_SWAP=n build] Signed-off-by: Shaohua Li <shli@fusionio.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Anton Vorontsov
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70ddf637ee |
memcg: add memory.pressure_level events
With this patch userland applications that want to maintain the interactivity/memory allocation cost can use the pressure level notifications. The levels are defined like this: The "low" level means that the system is reclaiming memory for new allocations. Monitoring this reclaiming activity might be useful for maintaining cache level. Upon notification, the program (typically "Activity Manager") might analyze vmstat and act in advance (i.e. prematurely shutdown unimportant services). The "medium" level means that the system is experiencing medium memory pressure, the system might be making swap, paging out active file caches, etc. Upon this event applications may decide to further analyze vmstat/zoneinfo/memcg or internal memory usage statistics and free any resources that can be easily reconstructed or re-read from a disk. The "critical" level means that the system is actively thrashing, it is about to out of memory (OOM) or even the in-kernel OOM killer is on its way to trigger. Applications should do whatever they can to help the system. It might be too late to consult with vmstat or any other statistics, so it's advisable to take an immediate action. The events are propagated upward until the event is handled, i.e. the events are not pass-through. Here is what this means: for example you have three cgroups: A->B->C. Now you set up an event listener on cgroups A, B and C, and suppose group C experiences some pressure. In this situation, only group C will receive the notification, i.e. groups A and B will not receive it. This is done to avoid excessive "broadcasting" of messages, which disturbs the system and which is especially bad if we are low on memory or thrashing. So, organize the cgroups wisely, or propagate the events manually (or, ask us to implement the pass-through events, explaining why would you need them.) Performance wise, the memory pressure notifications feature itself is lightweight and does not require much of bookkeeping, in contrast to the rest of memcg features. Unfortunately, as of current memcg implementation, pages accounting is an inseparable part and cannot be turned off. The good news is that there are some efforts[1] to improve the situation; plus, implementing the same, fully API-compatible[2] interface for CONFIG_MEMCG=n case (e.g. embedded) is also a viable option, so it will not require any changes on the userland side. [1] http://permalink.gmane.org/gmane.linux.kernel.cgroups/6291 [2] http://lkml.org/lkml/2013/2/21/454 [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix CONFIG_CGROPUPS=n warnings] Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org> Acked-by: Kirill A. Shutemov <kirill@shutemov.name> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Glauber Costa <glommer@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Luiz Capitulino <lcapitulino@redhat.com> Cc: Greg Thelen <gthelen@google.com> Cc: Leonid Moiseichuk <leonid.moiseichuk@nokia.com> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: John Stultz <john.stultz@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hillf Danton
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2d42a40d59 |
mm/vmscan.c: minor cleanup for kswapd
Local variable total_scanned is no longer used. Signed-off-by: Hillf Danton <dhillf@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Xishi Qiu
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d72515b85a |
mm/vmscan: fix error return in kswapd_run()
Fix the error return value in kswapd_run(). The bug was introduced by
commit
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Zhang Yanfei
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b21e0b90cc |
vmscan: change type of vm_total_pages to unsigned long
This variable is calculated from nr_free_pagecache_pages so change its type to unsigned long. Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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0e50ce3b50 |
mm: use up free swap space before reaching OOM kill
Recently, Luigi reported there are lots of free swap space when OOM
happens. It's easily reproduced on zram-over-swap, where many instance
of memory hogs are running and laptop_mode is enabled. He said there
was no problem when he disabled laptop_mode. The problem when I
investigate problem is following as.
Assumption for easy explanation: There are no page cache page in system
because they all are already reclaimed.
1. try_to_free_pages disable may_writepage when laptop_mode is enabled.
2. shrink_inactive_list isolates victim pages from inactive anon lru list.
3. shrink_page_list adds them to swapcache via add_to_swap but it doesn't
pageout because sc->may_writepage is 0 so the page is rotated back into
inactive anon lru list. The add_to_swap made the page Dirty by SetPageDirty.
4. 3 couldn't reclaim any pages so do_try_to_free_pages increase priority and
retry reclaim with higher priority.
5. shrink_inactlive_list try to isolate victim pages from inactive anon lru list
but got failed because it try to isolate pages with ISOLATE_CLEAN mode but
inactive anon lru list is full of dirty pages by 3 so it just returns
without any reclaim progress.
6. do_try_to_free_pages doesn't set may_writepage due to zero total_scanned.
Because sc->nr_scanned is increased by shrink_page_list but we don't call
shrink_page_list in 5 due to short of isolated pages.
Above loop is continued until OOM happens.
The problem didn't happen before [1] was merged because old logic's
isolatation in shrink_inactive_list was successful and tried to call
shrink_page_list to pageout them but it still ends up failed to page out
by may_writepage. But important point is that sc->nr_scanned was
increased although we couldn't swap out them so do_try_to_free_pages
could set may_writepages.
Since commit
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Johannes Weiner
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e3790144c9 |
mm: refactor inactive_file_is_low() to use get_lru_size()
An inactive file list is considered low when its active counterpart is bigger, regardless of whether it is a global zone LRU list or a memcg zone LRU list. The only difference is in how the LRU size is assessed. get_lru_size() does the right thing for both global and memcg reclaim situations. Get rid of inactive_file_is_low_global() and mem_cgroup_inactive_file_is_low() by using get_lru_size() and compare the numbers in common code. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Shaohua Li
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ec8acf20af |
swap: add per-partition lock for swapfile
swap_lock is heavily contended when I test swap to 3 fast SSD (even slightly slower than swap to 2 such SSD). The main contention comes from swap_info_get(). This patch tries to fix the gap with adding a new per-partition lock. Global data like nr_swapfiles, total_swap_pages, least_priority and swap_list are still protected by swap_lock. nr_swap_pages is an atomic now, it can be changed without swap_lock. In theory, it's possible get_swap_page() finds no swap pages but actually there are free swap pages. But sounds not a big problem. Accessing partition specific data (like scan_swap_map and so on) is only protected by swap_info_struct.lock. Changing swap_info_struct.flags need hold swap_lock and swap_info_struct.lock, because scan_scan_map() will check it. read the flags is ok with either the locks hold. If both swap_lock and swap_info_struct.lock must be hold, we always hold the former first to avoid deadlock. swap_entry_free() can change swap_list. To delete that code, we add a new highest_priority_index. Whenever get_swap_page() is called, we check it. If it's valid, we use it. It's a pity get_swap_page() still holds swap_lock(). But in practice, swap_lock() isn't heavily contended in my test with this patch (or I can say there are other much more heavier bottlenecks like TLB flush). And BTW, looks get_swap_page() doesn't really need the lock. We never free swap_info[] and we check SWAP_WRITEOK flag. The only risk without the lock is we could swapout to some low priority swap, but we can quickly recover after several rounds of swap, so sounds not a big deal to me. But I'd prefer to fix this if it's a real problem. "swap: make each swap partition have one address_space" improved the swapout speed from 1.7G/s to 2G/s. This patch further improves the speed to 2.3G/s, so around 15% improvement. It's a multi-process test, so TLB flush isn't the biggest bottleneck before the patches. [arnd@arndb.de: fix it for nommu] [hughd@google.com: add missing unlock] [minchan@kernel.org: get rid of lockdep whinge on sys_swapon] Signed-off-by: Shaohua Li <shli@fusionio.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Seth Jennings <sjenning@linux.vnet.ibm.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ming Lei
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21caf2fc19 |
mm: teach mm by current context info to not do I/O during memory allocation
This patch introduces PF_MEMALLOC_NOIO on process flag('flags' field of
'struct task_struct'), so that the flag can be set by one task to avoid
doing I/O inside memory allocation in the task's context.
The patch trys to solve one deadlock problem caused by block device, and
the problem may happen at least in the below situations:
- during block device runtime resume, if memory allocation with
GFP_KERNEL is called inside runtime resume callback of any one of its
ancestors(or the block device itself), the deadlock may be triggered
inside the memory allocation since it might not complete until the block
device becomes active and the involed page I/O finishes. The situation
is pointed out first by Alan Stern. It is not a good approach to
convert all GFP_KERNEL[1] in the path into GFP_NOIO because several
subsystems may be involved(for example, PCI, USB and SCSI may be
involved for usb mass stoarage device, network devices involved too in
the iSCSI case)
- during block device runtime suspend, because runtime resume need to
wait for completion of concurrent runtime suspend.
- during error handling of usb mass storage deivce, USB bus reset will
be put on the device, so there shouldn't have any memory allocation with
GFP_KERNEL during USB bus reset, otherwise the deadlock similar with
above may be triggered. Unfortunately, any usb device may include one
mass storage interface in theory, so it requires all usb interface
drivers to handle the situation. In fact, most usb drivers don't know
how to handle bus reset on the device and don't provide .pre_set() and
.post_reset() callback at all, so USB core has to unbind and bind driver
for these devices. So it is still not practical to resort to GFP_NOIO
for solving the problem.
Also the introduced solution can be used by block subsystem or block
drivers too, for example, set the PF_MEMALLOC_NOIO flag before doing
actual I/O transfer.
It is not a good idea to convert all these GFP_KERNEL in the affected
path into GFP_NOIO because these functions doing that may be implemented
as library and will be called in many other contexts.
In fact, memalloc_noio_flags() can convert some of current static
GFP_NOIO allocation into GFP_KERNEL back in other non-affected contexts,
at least almost all GFP_NOIO in USB subsystem can be converted into
GFP_KERNEL after applying the approach and make allocation with GFP_NOIO
only happen in runtime resume/bus reset/block I/O transfer contexts
generally.
[1], several GFP_KERNEL allocation examples in runtime resume path
- pci subsystem
acpi_os_allocate
<-acpi_ut_allocate
<-ACPI_ALLOCATE_ZEROED
<-acpi_evaluate_object
<-__acpi_bus_set_power
<-acpi_bus_set_power
<-acpi_pci_set_power_state
<-platform_pci_set_power_state
<-pci_platform_power_transition
<-__pci_complete_power_transition
<-pci_set_power_state
<-pci_restore_standard_config
<-pci_pm_runtime_resume
- usb subsystem
usb_get_status
<-finish_port_resume
<-usb_port_resume
<-generic_resume
<-usb_resume_device
<-usb_resume_both
<-usb_runtime_resume
- some individual usb drivers
usblp, uvc, gspca, most of dvb-usb-v2 media drivers, cpia2, az6007, ....
That is just what I have found. Unfortunately, this allocation can only
be found by human being now, and there should be many not found since
any function in the resume path(call tree) may allocate memory with
GFP_KERNEL.
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oneukum@suse.de>
Cc: Jiri Kosina <jiri.kosina@suse.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Greg KH <greg@kroah.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: David Decotigny <david.decotigny@google.com>
Cc: Tom Herbert <therbert@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Zlatko Calusic
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258401a60c |
mm: don't wait on congested zones in balance_pgdat()
From: Zlatko Calusic <zlatko.calusic@iskon.hr>
Commit
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Jiang Liu
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b40da04946 |
mm: use zone->present_pages instead of zone->managed_pages where appropriate
Now we have zone->managed_pages for "pages managed by the buddy system in the zone", so replace zone->present_pages with zone->managed_pages if what the user really wants is number of allocatable pages. Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Cc: Wen Congyang <wency@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Jiang Liu <jiang.liu@huawei.com> Cc: Maciej Rutecki <maciej.rutecki@gmail.com> Cc: Chris Clayton <chris2553@googlemail.com> Cc: "Rafael J . Wysocki" <rjw@sisk.pl> Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Jianguo Wu <wujianguo@huawei.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Zlatko Calusic
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dafcb73e38 |
mm: avoid calling pgdat_balanced() needlessly
Now that balance_pgdat() is slightly tidied up, thanks to more capable pgdat_balanced(), it's become obvious that pgdat_balanced() is called to check the status, then break the loop if pgdat is balanced, just to be immediately called again. The second call is completely unnecessary, of course. The patch introduces pgdat_is_balanced boolean, which helps resolve the above suboptimal behavior, with the added benefit of slightly better documenting one other place in the function where we jump and skip lots of code. Signed-off-by: Zlatko Calusic <zlatko.calusic@iskon.hr> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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a394cb8ee6 |
memcg,vmscan: do not break out targeted reclaim without reclaimed pages
Targeted (hard resp soft) reclaim has traditionally tried to scan one group with decreasing priority until nr_to_reclaim (SWAP_CLUSTER_MAX pages) is reclaimed or all priorities are exhausted. The reclaim is then retried until the limit is met. This approach, however, doesn't work well with deeper hierarchies where groups higher in the hierarchy do not have any or only very few pages (this usually happens if those groups do not have any tasks and they have only re-parented pages after some of their children is removed). Those groups are reclaimed with decreasing priority pointlessly as there is nothing to reclaim from them. An easiest fix is to break out of the memcg iteration loop in shrink_zone only if the whole hierarchy has been visited or sufficient pages have been reclaimed. This is also more natural because the reclaimer expects that the hierarchy under the given root is reclaimed. As a result we can simplify the soft limit reclaim which does its own iteration. [yinghan@google.com: break out of the hierarchy loop only if nr_reclaimed exceeded nr_to_reclaim] [akpm@linux-foundation.org: use conventional comparison order] Signed-off-by: Michal Hocko <mhocko@suse.cz> Reported-by: Ying Han <yinghan@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Tejun Heo <htejun@gmail.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Li Zefan <lizefan@huawei.com> Signed-off-by: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andrew Morton
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62b726c1b3 |
mm/vmscan.c:__zone_reclaim(): replace max_t() with max()
"mm: vmscan: save work scanning (almost) empty LRU lists" made SWAP_CLUSTER_MAX an unsigned long. Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Satoru Moriya <satoru.moriya@hds.com> Cc: Simon Jeons <simon.jeons@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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9b4f98cdac |
mm: vmscan: compaction works against zones, not lruvecs
The restart logic for when reclaim operates back to back with compaction is currently applied on the lruvec level. But this does not make sense, because the container of interest for compaction is a zone as a whole, not the zone pages that are part of a certain memory cgroup. Negative impact is bounded. For one, the code checks that the lruvec has enough reclaim candidates, so it does not risk getting stuck on a condition that can not be fulfilled. And the unfairness of hammering on one particular memory cgroup to make progress in a zone will be amortized by the round robin manner in which reclaim goes through the memory cgroups. Still, this can lead to unnecessary allocation latencies when the code elects to restart on a hard to reclaim or small group when there are other, more reclaimable groups in the zone. Move this logic to the zone level and restart reclaim for all memory cgroups in a zone when compaction requires more free pages from it. [akpm@linux-foundation.org: no need for min_t] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Satoru Moriya <satoru.moriya@hds.com> Cc: Simon Jeons <simon.jeons@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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9a2651140e |
mm: vmscan: clean up get_scan_count()
Reclaim pressure balance between anon and file pages is calculated
through a tuple of numerators and a shared denominator.
Exceptional cases that want to force-scan anon or file pages configure
the numerators and denominator such that one list is preferred, which is
not necessarily the most obvious way:
fraction[0] = 1;
fraction[1] = 0;
denominator = 1;
goto out;
Make this easier by making the force-scan cases explicit and use the
fractionals only in case they are calculated from reclaim history.
[akpm@linux-foundation.org: avoid using unintialized_var()]
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Satoru Moriya <satoru.moriya@hds.com>
Cc: Simon Jeons <simon.jeons@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Johannes Weiner
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11d16c25bb |
mm: vmscan: improve comment on low-page cache handling
Fix comment style and elaborate on why anonymous memory is force-scanned when file cache runs low. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Satoru Moriya <satoru.moriya@hds.com> Cc: Simon Jeons <simon.jeons@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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10316b313c |
mm: vmscan: clarify how swappiness, highest priority, memcg interact
A swappiness of 0 has a slightly different meaning for global reclaim (may swap if file cache really low) and memory cgroup reclaim (never swap, ever). In addition, global reclaim at highest priority will scan all LRU lists equal to their size and ignore other balancing heuristics. UNLESS swappiness forbids swapping, then the lists are balanced based on recent reclaim effectiveness. UNLESS file cache is running low, then anonymous pages are force-scanned. This (total mess of a) behaviour is implicit and not obvious from the way the code is organized. At least make it apparent in the code flow and document the conditions. It will be it easier to come up with sane semantics later. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Satoru Moriya <satoru.moriya@hds.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Cc: Simon Jeons <simon.jeons@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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d778df51c0 |
mm: vmscan: save work scanning (almost) empty LRU lists
In certain cases (kswapd reclaim, memcg target reclaim), a fixed minimum amount of pages is scanned from the LRU lists on each iteration, to make progress. Do not make this minimum bigger than the respective LRU list size, however, and save some busy work trying to isolate and reclaim pages that are not there. Empty LRU lists are quite common with memory cgroups in NUMA environments because there exists a set of LRU lists for each zone for each memory cgroup, while the memory of a single cgroup is expected to stay on just one node. The number of expected empty LRU lists is thus memcgs * (nodes - 1) * lru types Each attempt to reclaim from an empty LRU list does expensive size comparisons between lists, acquires the zone's lru lock etc. Avoid that. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Satoru Moriya <satoru.moriya@hds.com> Cc: Simon Jeons <simon.jeons@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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7c5bd705d8 |
mm: memcg: only evict file pages when we have plenty
Commit
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Greg Kroah-Hartman
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fcb35a9bac |
MM: vmscan: remove __devinit attribute.
CONFIG_HOTPLUG is going away as an option. As a result, the __dev* markings need to be removed. This change removes the use of __devinit from the file. Based on patches originally written by Bill Pemberton, but redone by me in order to handle some of the coding style issues better, by hand. Cc: Bill Pemberton <wfp5p@virginia.edu> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
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Zlatko Calusic
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ecccd1248d |
mm: fix null pointer dereference in wait_iff_congested()
An unintended consequence of commit
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Zlatko Calusic
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4ae0a48b5e |
mm: modify pgdat_balanced() so that it also handles order-0
Teach pgdat_balanced() about order-0 allocations so that we can simplify code in a few places in vmstat.c. Suggested-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Zlatko Calusic <zlatko.calusic@iskon.hr> Cc: Mel Gorman <mgorman@suse.de> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Zlatko Calusic
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cda73a10eb |
mm: do not sleep in balance_pgdat if there's no i/o congestion
On a 4GB RAM machine, where Normal zone is much smaller than DMA32 zone, the Normal zone gets fragmented in time. This requires relatively more pressure in balance_pgdat to get the zone above the required watermark. Unfortunately, the congestion_wait() call in there slows it down for a completely wrong reason, expecting that there's a lot of writeback/swapout, even when there's none (much more common). After a few days, when fragmentation progresses, this flawed logic translates to a very high CPU iowait times, even though there's no I/O congestion at all. If THP is enabled, the problem occurs sooner, but I was able to see it even on !THP kernels, just by giving it a bit more time to occur. The proper way to deal with this is to not wait, unless there's congestion. Thanks to Mel Gorman, we already have the function that perfectly fits the job. The patch was tested on a machine which nicely revealed the problem after only 1 day of uptime, and it's been working great. Signed-off-by: Zlatko Calusic <zlatko.calusic@iskon.hr> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Fengguang Wu
|
3cf23841b4 |
mm/vmscan.c: avoid possible deadlock caused by too_many_isolated()
Neil found that if too_many_isolated() returns true while performing
direct reclaim we can end up waiting for other threads to complete their
direct reclaim. If those threads are allowed to enter the FS or IO to
free memory, but this thread is not, then it is possible that those
threads will be waiting on this thread and so we get a circular deadlock.
some task enters direct reclaim with GFP_KERNEL
=> too_many_isolated() false
=> vmscan and run into dirty pages
=> pageout()
=> take some FS lock
=> fs/block code does GFP_NOIO allocation
=> enter direct reclaim again
=> too_many_isolated() true
=> waiting for others to progress, however the other
tasks may be circular waiting for the FS lock..
The fix is to let !__GFP_IO and !__GFP_FS direct reclaims enjoy higher
priority than normal ones, by lowering the throttle threshold for the
latter.
Allowing ~1/8 isolated pages in normal is large enough. For example, for
a 1GB LRU list, that's ~128MB isolated pages, or 1k blocked tasks (each
isolates 32 4KB pages), or 64 blocked tasks per logical CPU (assuming 16
logical CPUs per NUMA node). So it's not likely some CPU goes idle
waiting (when it could make progress) because of this limit: there are
much more sleeping reclaim tasks than the number of CPU, so the task may
well be blocked by some low level queue/lock anyway.
Now !GFP_IOFS reclaims won't be waiting for GFP_IOFS reclaims to progress.
They will be blocked only when there are too many concurrent !GFP_IOFS
reclaims, however that's very unlikely because the IO-less direct reclaims
is able to progress much more faster, and they won't deadlock each other.
The threshold is raised high enough for them, so that there can be
sufficient parallel progress of !GFP_IOFS reclaims.
[akpm@linux-foundation.org: tweak comment]
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Torsten Kaiser <just.for.lkml@googlemail.com>
Tested-by: NeilBrown <neilb@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Fengguang Wu
|
d37dd5dcb9 |
vmscan: comment too_many_isolated()
Comment "Why it's doing so" rather than "What it does" as proposed by Andrew Morton. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Lai Jiangshan
|
48fb2e240c |
vmscan: use N_MEMORY instead N_HIGH_MEMORY
N_HIGH_MEMORY stands for the nodes that has normal or high memory. N_MEMORY stands for the nodes that has any memory. The code here need to handle with the nodes which have memory, we should use N_MEMORY instead. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Cc: Christoph Lameter <cl@linux.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Lin Feng <linfeng@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Jeff Liu
|
6f6313d487 |
mm/vmscan.c: try_to_freeze() returns boolean
kswapd()->try_to_freeze() is defined to return a boolean, so it's better to use a bool to hold its return value. Signed-off-by: Jie Liu <jeff.liu@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rik van Riel
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e986850598 |
mm,vmscan: only evict file pages when we have plenty
If we have more inactive file pages than active file pages, we skip scanning the active file pages altogether, with the idea that we do not want to evict the working set when there is plenty of streaming IO in the cache. However, the code forgot to also skip scanning anonymous pages in that situation. That leads to the curious situation of keeping the active file pages protected from being paged out when there are lots of inactive file pages, while still scanning and evicting anonymous pages. This patch fixes that situation, by only evicting file pages when we have plenty of them and most are inactive. [akpm@linux-foundation.org: adjust comment layout] Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kirill A. Shutemov
|
d84da3f9e4 |
mm: use IS_ENABLED(CONFIG_COMPACTION) instead of COMPACTION_BUILD
We don't need custom COMPACTION_BUILD anymore, since we have handy IS_ENABLED(). Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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ed23ec4f0a |
mm: vmscan: fix inappropriate zone congestion clearing
commit
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Johannes Weiner
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c702418f8a |
mm: vmscan: do not keep kswapd looping forever due to individual uncompactable zones
When a zone meets its high watermark and is compactable in case of higher order allocations, it contributes to the percentage of the node's memory that is considered balanced. This requirement, that a node be only partially balanced, came about when kswapd was desparately trying to balance tiny zones when all bigger zones in the node had plenty of free memory. Arguably, the same should apply to compaction: if a significant part of the node is balanced enough to run compaction, do not get hung up on that tiny zone that might never get in shape. When the compaction logic in kswapd is reached, we know that at least 25% of the node's memory is balanced properly for compaction (see zone_balanced and pgdat_balanced). Remove the individual zone checks that restart the kswapd cycle. Otherwise, we may observe more endless looping in kswapd where the compaction code loops back to reclaim because of a single zone and reclaim does nothing because the node is considered balanced overall. See for example https://bugzilla.redhat.com/show_bug.cgi?id=866988 Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-and-tested-by: Thorsten Leemhuis <fedora@leemhuis.info> Reported-by: Jiri Slaby <jslaby@suse.cz> Tested-by: John Ellson <john.ellson@comcast.net> Tested-by: Zdenek Kabelac <zkabelac@redhat.com> Tested-by: Bruno Wolff III <bruno@wolff.to> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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60cefed485 |
mm: vmscan: fix endless loop in kswapd balancing
Kswapd does not in all places have the same criteria for a balanced zone. Zones are only being reclaimed when their high watermark is breached, but compaction checks loop over the zonelist again when the zone does not meet the low watermark plus two times the size of the allocation. This gets kswapd stuck in an endless loop over a small zone, like the DMA zone, where the high watermark is smaller than the compaction requirement. Add a function, zone_balanced(), that checks the watermark, and, for higher order allocations, if compaction has enough free memory. Then use it uniformly to check for balanced zones. This makes sure that when the compaction watermark is not met, at least reclaim happens and progress is made - or the zone is declared unreclaimable at some point and skipped entirely. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: George Spelvin <linux@horizon.com> Reported-by: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de> Reported-by: Tomas Racek <tracek@redhat.com> Tested-by: Johannes Hirte <johannes.hirte@fem.tu-ilmenau.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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50694c28f1 |
mm: vmscan: check for fatal signals iff the process was throttled
Commit
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Mel Gorman
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96710098ee |
mm: revert "mm: vmscan: scale number of pages reclaimed by reclaim/compaction based on failures"
Jiri Slaby reported the following: (It's an effective revert of "mm: vmscan: scale number of pages reclaimed by reclaim/compaction based on failures".) Given kswapd had hours of runtime in ps/top output yesterday in the morning and after the revert it's now 2 minutes in sum for the last 24h, I would say, it's gone. The intention of the patch in question was to compensate for the loss of lumpy reclaim. Part of the reason lumpy reclaim worked is because it aggressively reclaimed pages and this patch was meant to be a sane compromise. When compaction fails, it gets deferred and both compaction and reclaim/compaction is deferred avoid excessive reclaim. However, since commit |
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Takamori Yamaguchi
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b0a8cc58e6 |
mm: bugfix: set current->reclaim_state to NULL while returning from kswapd()
In kswapd(), set current->reclaim_state to NULL before returning, as current->reclaim_state holds reference to variable on kswapd()'s stack. In rare cases, while returning from kswapd() during memory offlining, __free_slab() and freepages() can access the dangling pointer of current->reclaim_state. Signed-off-by: Takamori Yamaguchi <takamori.yamaguchi@jp.sony.com> Signed-off-by: Aaditya Kumar <aaditya.kumar@ap.sony.com> Acked-by: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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e46a28790e |
CMA: migrate mlocked pages
Presently CMA cannot migrate mlocked pages so it ends up failing to allocate contiguous memory space. This patch makes mlocked pages be migrated out. Of course, it can affect realtime processes but in CMA usecase, contiguous memory allocation failing is far worse than access latency to an mlocked page being variable while CMA is running. If someone wants to make the system realtime, he shouldn't enable CMA because stalls can still happen at random times. [akpm@linux-foundation.org: tweak comment text, per Mel] Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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39b5f29ac1 |
mm: remove vma arg from page_evictable
page_evictable(page, vma) is an irritant: almost all its callers pass NULL for vma. Remove the vma arg and use mlocked_vma_newpage(vma, page) explicitly in the couple of places it's needed. But in those places we don't even need page_evictable() itself! They're dealing with a freshly allocated anonymous page, which has no "mapping" and cannot be mlocked yet. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michel Lespinasse <walken@google.com> Cc: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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62997027ca |
mm: compaction: clear PG_migrate_skip based on compaction and reclaim activity
Compaction caches if a pageblock was scanned and no pages were isolated so that the pageblocks can be skipped in the future to reduce scanning. This information is not cleared by the page allocator based on activity due to the impact it would have to the page allocator fast paths. Hence there is a requirement that something clear the cache or pageblocks will be skipped forever. Currently the cache is cleared if there were a number of recent allocation failures and it has not been cleared within the last 5 seconds. Time-based decisions like this are terrible as they have no relationship to VM activity and is basically a big hammer. Unfortunately, accurate heuristics would add cost to some hot paths so this patch implements a rough heuristic. There are two cases where the cache is cleared. 1. If a !kswapd process completes a compaction cycle (migrate and free scanner meet), the zone is marked compact_blockskip_flush. When kswapd goes to sleep, it will clear the cache. This is expected to be the common case where the cache is cleared. It does not really matter if kswapd happens to be asleep or going to sleep when the flag is set as it will be woken on the next allocation request. 2. If there have been multiple failures recently and compaction just finished being deferred then a process will clear the cache and start a full scan. This situation happens if there are multiple high-order allocation requests under heavy memory pressure. The clearing of the PG_migrate_skip bits and other scans is inherently racy but the race is harmless. For allocations that can fail such as THP, they will simply fail. For requests that cannot fail, they will retry the allocation. Tests indicated that scanning rates were roughly similar to when the time-based heuristic was used and the allocation success rates were similar. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Richard Davies <richard@arachsys.com> Cc: Shaohua Li <shli@kernel.org> Cc: Avi Kivity <avi@redhat.com> Cc: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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02c6de8d75 |
mm: cma: discard clean pages during contiguous allocation instead of migration
Drop clean cache pages instead of migration during alloc_contig_range() to minimise allocation latency by reducing the amount of migration that is necessary. It's useful for CMA because latency of migration is more important than evicting the background process's working set. In addition, as pages are reclaimed then fewer free pages for migration targets are required so it avoids memory reclaiming to get free pages, which is a contributory factor to increased latency. I measured elapsed time of __alloc_contig_migrate_range() which migrates 10M in 40M movable zone in QEMU machine. Before - 146ms, After - 7ms [akpm@linux-foundation.org: fix nommu build] Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Mel Gorman <mgorman@suse.de> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Cc: Rik van Riel <riel@redhat.com> Tested-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Gavin Shan
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d5dc0ad928 |
mm/vmscan: fix error number for failed kthread
Fix the return value while failing to create the kswapd kernel thread. Also, the error message is prioritized as KERN_ERR. Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com> Signed-off-by: Wanpeng Li <liwanp@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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83fde0f228 |
mm: vmscan: scale number of pages reclaimed by reclaim/compaction based on failures
If allocation fails after compaction then compaction may be deferred for a number of allocation attempts. If there are subsequent failures, compact_defer_shift is increased to defer for longer periods. This patch uses that information to scale the number of pages reclaimed with compact_defer_shift until allocations succeed again. The rationale is that reclaiming the normal number of pages still allowed compaction to fail and its success depends on the number of pages. If it's failing, reclaim more pages until it succeeds again. Note that this is not implying that VM reclaim is not reclaiming enough pages or that its logic is broken. try_to_free_pages() always asks for SWAP_CLUSTER_MAX pages to be reclaimed regardless of order and that is what it does. Direct reclaim stops normally with this check. if (sc->nr_reclaimed >= sc->nr_to_reclaim) goto out; should_continue_reclaim delays when that check is made until a minimum number of pages for reclaim/compaction are reclaimed. It is possible that this patch could instead set nr_to_reclaim in try_to_free_pages() and drive it from there but that's behaves differently and not necessarily for the better. If driven from do_try_to_free_pages(), it is also possible that priorities will rise. When they reach DEF_PRIORITY-2, it will also start stalling and setting pages for immediate reclaim which is more disruptive than not desirable in this case. That is a more wide-reaching change that could cause another regression related to THP requests causing interactive jitter. [akpm@linux-foundation.org: fix build] Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Wen Congyang
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18b48d5873 |
memory hotplug: reset pgdat->kswapd to NULL if creating kernel thread fails
If kthread_run() fails, pgdat->kswapd contains errno. When we stop this thread, we only check whether pgdat->kswapd is NULL and access it. If it contains errno, it will cause page fault. Reset pgdat->kswapd to NULL when creating kernel thread fails can avoid this problem. Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tim Chen
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69980e3175 |
memcg: gix memory accounting scalability in shrink_page_list
I noticed in a multi-process parallel files reading benchmark I ran on a 8
socket machine, throughput slowed down by a factor of 8 when I ran the
benchmark within a cgroup container. I traced the problem to the
following code path (see below) when we are trying to reclaim memory from
file cache. The res_counter_uncharge function is called on every page
that's reclaimed and created heavy lock contention. The patch below
allows the reclaimed pages to be uncharged from the resource counter in
batch and recovered the regression.
Tim
40.67% usemem [kernel.kallsyms] [k] _raw_spin_lock
|
--- _raw_spin_lock
|
|--92.61%-- res_counter_uncharge
| |
| |--100.00%-- __mem_cgroup_uncharge_common
| | |
| | |--100.00%-- mem_cgroup_uncharge_cache_page
| | | __remove_mapping
| | | shrink_page_list
| | | shrink_inactive_list
| | | shrink_mem_cgroup_zone
| | | shrink_zone
| | | do_try_to_free_pages
| | | try_to_free_pages
| | | __alloc_pages_nodemask
| | | alloc_pages_current
Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Hugh Dickins
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c3b94f44fc |
memcg: further prevent OOM with too many dirty pages
The may_enter_fs test turns out to be too restrictive: though I saw no problem with it when testing on 3.5-rc6, it very soon OOMed when I tested on 3.5-rc6-mm1. I don't know what the difference there is, perhaps I just slightly changed the way I started off the testing: dd if=/dev/zero of=/mnt/temp bs=1M count=1024; rm -f /mnt/temp; sync repeatedly, in 20M memory.limit_in_bytes cgroup to ext4 on USB stick. ext4 (and gfs2 and xfs) turn out to allocate new pages for writing with AOP_FLAG_NOFS: that seems a little worrying, and it's unclear to me why the transaction needs to be started even before allocating pagecache memory. But it may not be worth worrying about these days: if direct reclaim avoids FS writeback, does __GFP_FS now mean anything? Anyway, we insisted on the may_enter_fs test to avoid hangs with the loop device; but since that also masks off __GFP_IO, we can test for __GFP_IO directly, ignoring may_enter_fs and __GFP_FS. But even so, the test still OOMs sometimes: when originally testing on 3.5-rc6, it OOMed about one time in five or ten; when testing just now on 3.5-rc6-mm1, it OOMed on the first iteration. This residual problem comes from an accumulation of pages under ordinary writeback, not marked PageReclaim, so rightly not causing the memcg check to wait on their writeback: these too can prevent shrink_page_list() from freeing any pages, so many times that memcg reclaim fails and OOMs. Deal with these in the same way as direct reclaim now deals with dirty FS pages: mark them PageReclaim. It is appropriate to rotate these to tail of list when writepage completes, but more importantly, the PageReclaim flag makes memcg reclaim wait on them if encountered again. Increment NR_VMSCAN_IMMEDIATE? That's arguable: I chose not. Setting PageReclaim here may occasionally race with end_page_writeback() clearing it: lru_deactivate_fn() already faced the same race, and correctly concluded that the window is small and the issue non-critical. With these changes, the test runs indefinitely without OOMing on ext4, ext3 and ext2: I'll move on to test with other filesystems later. Trivia: invert conditions for a clearer block without an else, and goto keep_locked to do the unlock_page. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Dave Chinner <david@fromorbit.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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e62e384e9d |
memcg: prevent OOM with too many dirty pages
The current implementation of dirty pages throttling is not memcg aware which makes it easy to have memcg LRUs full of dirty pages. Without throttling, these LRUs can be scanned faster than the rate of writeback, leading to memcg OOM conditions when the hard limit is small. This patch fixes the problem by throttling the allocating process (possibly a writer) during the hard limit reclaim by waiting on PageReclaim pages. We are waiting only for PageReclaim pages because those are the pages that made one full round over LRU and that means that the writeback is much slower than scanning. The solution is far from being ideal - long term solution is memcg aware dirty throttling - but it is meant to be a band aid until we have a real fix. We are seeing this happening during nightly backups which are placed into containers to prevent from eviction of the real working set. The change affects only memcg reclaim and only when we encounter PageReclaim pages which is a signal that the reclaim doesn't catch up on with the writers so somebody should be throttled. This could be potentially unfair because it could be somebody else from the group who gets throttled on behalf of the writer but as writers need to allocate as well and they allocate in higher rate the probability that only innocent processes would be penalized is not that high. I have tested this change by a simple dd copying /dev/zero to tmpfs or ext3 running under small memcg (1G copy under 5M, 60M, 300M and 2G containers) and dd got killed by OOM killer every time. With the patch I could run the dd with the same size under 5M controller without any OOM. The issue is more visible with slower devices for output. * With the patch ================ * tmpfs size=2G --------------- $ vim cgroup_cache_oom_test.sh $ ./cgroup_cache_oom_test.sh 5M using Limit 5M for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 30.4049 s, 34.5 MB/s $ ./cgroup_cache_oom_test.sh 60M using Limit 60M for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 31.4561 s, 33.3 MB/s $ ./cgroup_cache_oom_test.sh 300M using Limit 300M for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 20.4618 s, 51.2 MB/s $ ./cgroup_cache_oom_test.sh 2G using Limit 2G for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 1.42172 s, 738 MB/s * ext3 ------ $ ./cgroup_cache_oom_test.sh 5M using Limit 5M for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 27.9547 s, 37.5 MB/s $ ./cgroup_cache_oom_test.sh 60M using Limit 60M for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 30.3221 s, 34.6 MB/s $ ./cgroup_cache_oom_test.sh 300M using Limit 300M for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 24.5764 s, 42.7 MB/s $ ./cgroup_cache_oom_test.sh 2G using Limit 2G for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 3.35828 s, 312 MB/s * Without the patch =================== * tmpfs size=2G --------------- $ ./cgroup_cache_oom_test.sh 5M using Limit 5M for group ./cgroup_cache_oom_test.sh: line 46: 4668 Killed dd if=/dev/zero of=$OUT/zero bs=1M count=$count $ ./cgroup_cache_oom_test.sh 60M using Limit 60M for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 25.4989 s, 41.1 MB/s $ ./cgroup_cache_oom_test.sh 300M using Limit 300M for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 24.3928 s, 43.0 MB/s $ ./cgroup_cache_oom_test.sh 2G using Limit 2G for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 1.49797 s, 700 MB/s * ext3 ------ $ ./cgroup_cache_oom_test.sh 5M using Limit 5M for group ./cgroup_cache_oom_test.sh: line 46: 4689 Killed dd if=/dev/zero of=$OUT/zero bs=1M count=$count $ ./cgroup_cache_oom_test.sh 60M using Limit 60M for group ./cgroup_cache_oom_test.sh: line 46: 4692 Killed dd if=/dev/zero of=$OUT/zero bs=1M count=$count $ ./cgroup_cache_oom_test.sh 300M using Limit 300M for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 20.248 s, 51.8 MB/s $ ./cgroup_cache_oom_test.sh 2G using Limit 2G for group 1000+0 records in 1000+0 records out 1048576000 bytes (1.0 GB) copied, 2.85201 s, 368 MB/s [akpm@linux-foundation.org: tweak changelog, reordered the test to optimize for CONFIG_CGROUP_MEM_RES_CTLR=n] [hughd@google.com: fix deadlock with loop driver] Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Hugh Dickins <hughd@google.com> Reviewed-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
|
68243e76ee |
mm: account for the number of times direct reclaimers get throttled
Under significant pressure when writing back to network-backed storage, direct reclaimers may get throttled. This is expected to be a short-lived event and the processes get woken up again but processes do get stalled. This patch counts how many times such stalling occurs. It's up to the administrator whether to reduce these stalls by increasing min_free_kbytes. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
|
5515061d22 |
mm: throttle direct reclaimers if PF_MEMALLOC reserves are low and swap is backed by network storage
If swap is backed by network storage such as NBD, there is a risk that a large number of reclaimers can hang the system by consuming all PF_MEMALLOC reserves. To avoid these hangs, the administrator must tune min_free_kbytes in advance which is a bit fragile. This patch throttles direct reclaimers if half the PF_MEMALLOC reserves are in use. If the system is routinely getting throttled the system administrator can increase min_free_kbytes so degradation is smoother but the system will keep running. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andrew Morton
|
c255a45805 |
memcg: rename config variables
Sanity: CONFIG_CGROUP_MEM_RES_CTLR -> CONFIG_MEMCG CONFIG_CGROUP_MEM_RES_CTLR_SWAP -> CONFIG_MEMCG_SWAP CONFIG_CGROUP_MEM_RES_CTLR_SWAP_ENABLED -> CONFIG_MEMCG_SWAP_ENABLED CONFIG_CGROUP_MEM_RES_CTLR_KMEM -> CONFIG_MEMCG_KMEM [mhocko@suse.cz: fix missed bits] Cc: Glauber Costa <glommer@parallels.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Tejun Heo <tj@kernel.org> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: David Rientjes <rientjes@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
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d14b7a419a |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull trivial tree from Jiri Kosina: "Trivial updates all over the place as usual." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (29 commits) Fix typo in include/linux/clk.h . pci: hotplug: Fix typo in pci iommu: Fix typo in iommu video: Fix typo in drivers/video Documentation: Add newline at end-of-file to files lacking one arm,unicore32: Remove obsolete "select MISC_DEVICES" module.c: spelling s/postition/position/g cpufreq: Fix typo in cpufreq driver trivial: typo in comment in mksysmap mach-omap2: Fix typo in debug message and comment scsi: aha152x: Fix sparse warning and make printing pointer address more portable. Change email address for Steve Glendinning Btrfs: fix typo in convert_extent_bit via: Remove bogus if check netprio_cgroup.c: fix comment typo backlight: fix memory leak on obscure error path Documentation: asus-laptop.txt references an obsolete Kconfig item Documentation: ManagementStyle: fixed typo mm/vmscan: cleanup comment error in balance_pgdat mm: cleanup on the comments of zone_reclaim_stat ... |
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Aaditya Kumar
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1c7e7f6c07 |
mm: fix lost kswapd wakeup in kswapd_stop()
Offlining memory may block forever, waiting for kswapd() to wake up
because kswapd() does not check the event kthread->should_stop before
sleeping.
The proper pattern, from Documentation/memory-barriers.txt, is:
--- waker ---
event_indicated = 1;
wake_up_process(event_daemon);
--- sleeper ---
for (;;) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (event_indicated)
break;
schedule();
}
set_current_state() may be wrapped by:
prepare_to_wait();
In the kswapd() case, event_indicated is kthread->should_stop.
=== offlining memory (waker) ===
kswapd_stop()
kthread_stop()
kthread->should_stop = 1
wake_up_process()
wait_for_completion()
=== kswapd_try_to_sleep (sleeper) ===
kswapd_try_to_sleep()
prepare_to_wait()
.
.
schedule()
.
.
finish_wait()
The schedule() needs to be protected by a test of kthread->should_stop,
which is wrapped by kthread_should_stop().
Reproducer:
Do heavy file I/O in background.
Do a memory offline/online in a tight loop
Signed-off-by: Aaditya Kumar <aaditya.kumar@ap.sony.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Jiang Liu
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d8adde17e5 |
memory hotplug: fix invalid memory access caused by stale kswapd pointer
kswapd_stop() is called to destroy the kswapd work thread when all memory of a NUMA node has been offlined. But kswapd_stop() only terminates the work thread without resetting NODE_DATA(nid)->kswapd to NULL. The stale pointer will prevent kswapd_run() from creating a new work thread when adding memory to the memory-less NUMA node again. Eventually the stale pointer may cause invalid memory access. An example stack dump as below. It's reproduced with 2.6.32, but latest kernel has the same issue. BUG: unable to handle kernel NULL pointer dereference at (null) IP: [<ffffffff81051a94>] exit_creds+0x12/0x78 PGD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/system/memory/memory391/state CPU 11 Modules linked in: cpufreq_conservative cpufreq_userspace cpufreq_powersave acpi_cpufreq microcode fuse loop dm_mod tpm_tis rtc_cmos i2c_i801 rtc_core tpm serio_raw pcspkr sg tpm_bios igb i2c_core iTCO_wdt rtc_lib mptctl iTCO_vendor_support button dca bnx2 usbhid hid uhci_hcd ehci_hcd usbcore sd_mod crc_t10dif edd ext3 mbcache jbd fan ide_pci_generic ide_core ata_generic ata_piix libata thermal processor thermal_sys hwmon mptsas mptscsih mptbase scsi_transport_sas scsi_mod Pid: 7949, comm: sh Not tainted 2.6.32.12-qiuxishi-5-default #92 Tecal RH2285 RIP: 0010:exit_creds+0x12/0x78 RSP: 0018:ffff8806044f1d78 EFLAGS: 00010202 RAX: 0000000000000000 RBX: ffff880604f22140 RCX: 0000000000019502 RDX: 0000000000000000 RSI: 0000000000000202 RDI: 0000000000000000 RBP: ffff880604f22150 R08: 0000000000000000 R09: ffffffff81a4dc10 R10: 00000000000032a0 R11: ffff880006202500 R12: 0000000000000000 R13: 0000000000c40000 R14: 0000000000008000 R15: 0000000000000001 FS: 00007fbc03d066f0(0000) GS:ffff8800282e0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000000 CR3: 000000060f029000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process sh (pid: 7949, threadinfo ffff8806044f0000, task ffff880603d7c600) Stack: ffff880604f22140 ffffffff8103aac5 ffff880604f22140 ffffffff8104d21e ffff880006202500 0000000000008000 0000000000c38000 ffffffff810bd5b1 0000000000000000 ffff880603d7c600 00000000ffffdd29 0000000000000003 Call Trace: __put_task_struct+0x5d/0x97 kthread_stop+0x50/0x58 offline_pages+0x324/0x3da memory_block_change_state+0x179/0x1db store_mem_state+0x9e/0xbb sysfs_write_file+0xd0/0x107 vfs_write+0xad/0x169 sys_write+0x45/0x6e system_call_fastpath+0x16/0x1b Code: ff 4d 00 0f 94 c0 84 c0 74 08 48 89 ef e8 1f fd ff ff 5b 5d 31 c0 41 5c c3 53 48 8b 87 20 06 00 00 48 89 fb 48 8b bf 18 06 00 00 <8b> 00 48 c7 83 18 06 00 00 00 00 00 00 f0 ff 0f 0f 94 c0 84 c0 RIP exit_creds+0x12/0x78 RSP <ffff8806044f1d78> CR2: 0000000000000000 [akpm@linux-foundation.org: add pglist_data.kswapd locking comments] Signed-off-by: Xishi Qiu <qiuxishi@huawei.com> Signed-off-by: Jiang Liu <jiang.liu@huawei.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Jiri Kosina
|
59f91e5dd0 |
Merge branch 'master' into for-next
Conflicts: include/linux/mmzone.h Synced with Linus' tree so that trivial patch can be applied on top of up-to-date code properly. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> |
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Wanpeng Li
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ab8704b8c6 |
mm/vmscan: cleanup comment error in balance_pgdat
Signed-off-by: Wanpeng Li <liwp.linux@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
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Wanpeng Li
|
be7bd59db7 |
mm: fix page reclaim comment error
Since there are five lists in LRU cache, the array nr in get_scan_count should be: nr[0] = anon inactive pages to scan; nr[1] = anon active pages to scan nr[2] = file inactive pages to scan; nr[3] = file active pages to scan Signed-off-by: Wanpeng Li <liwp.linux@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Minchan Kim <minchan@kernel.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
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Hugh Dickins
|
fa9add641b |
mm/memcg: apply add/del_page to lruvec
Take lruvec further: pass it instead of zone to add_page_to_lru_list() and del_page_from_lru_list(); and pagevec_lru_move_fn() pass lruvec down to its target functions. This cleanup eliminates a swathe of cruft in memcontrol.c, including mem_cgroup_lru_add_list(), mem_cgroup_lru_del_list() and mem_cgroup_lru_move_lists() - which never actually touched the lists. In their place, mem_cgroup_page_lruvec() to decide the lruvec, previously a side-effect of add, and mem_cgroup_update_lru_size() to maintain the lru_size stats. Whilst these are simplifications in their own right, the goal is to bring the evaluation of lruvec next to the spin_locking of the lrus, in preparation for a future patch. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
|
75b00af77e |
mm: trivial cleanups in vmscan.c
Utter trivia in mm/vmscan.c, mostly just reducing the linecount slightly; most exciting change being get_scan_count() calling vmscan_swappiness() once instead of twice. Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Hugh Dickins
|
4d7dcca213 |
mm/memcg: get_lru_size not get_lruvec_size
Konstantin just introduced mem_cgroup_get_lruvec_size() and get_lruvec_size(), I'm about to add mem_cgroup_update_lru_size(): but we're dealing with the same thing, lru_size[lru]. We ought to agree on the naming, and I do think lru_size is the more correct: so rename his ones to get_lru_size(). Signed-off-by: Hugh Dickins <hughd@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Konstantin Khlebnikov
|
f9be23d6da |
mm/vmscan: kill struct mem_cgroup_zone
Kill struct mem_cgroup_zone and rename shrink_mem_cgroup_zone() to shrink_lruvec(), it always shrinks one lruvec which it takes as an argument. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Konstantin Khlebnikov
|
90bdcfafdc |
mm/vmscan: push lruvec pointer into should_continue_reclaim()
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Konstantin Khlebnikov
|
90126375d8 |
mm/vmscan: push lruvec pointer into get_scan_count()
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Konstantin Khlebnikov
|
1a93be0e7a |
mm/vmscan: push lruvec pointer into shrink_list()
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Konstantin Khlebnikov
|
c56d5c7dfe |
mm/vmscan: push lruvec pointer into inactive_list_is_low()
Switch mem_cgroup_inactive_anon_is_low() to lruvec pointers, mem_cgroup_get_lruvec_size() is more effective than mem_cgroup_zone_nr_lru_pages() Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Konstantin Khlebnikov
|
074291fea8 |
mm/vmscan: replace zone_nr_lru_pages() with get_lruvec_size()
If memory cgroup is enabled we always use lruvecs which are embedded into struct mem_cgroup_per_zone, so we can reach lru_size counters via container_of(). Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Konstantin Khlebnikov
|
27ac81d85e |
mm/vmscan: push lruvec pointer into putback_inactive_pages()
As zone_reclaim_stat is now located in the lruvec, we can reach it directly. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Konstantin Khlebnikov
|
95d918fc00 |
mm/vmscan: remove update_isolated_counts()
update_isolated_counts() is no longer required, because lumpy-reclaim was removed. Insanity is over, now there is only one kind of inactive page. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Konstantin Khlebnikov
|
6a18adb35c |
mm/vmscan: push zone pointer into shrink_page_list()
It doesn't need a pointer to the cgroup - pointer to the zone is enough. This patch also kills the "mz" argument of page_check_references() - it is unused after "mm: memcg: count pte references from every member of the reclaimed hierarch" Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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5dc35979e4 |
mm/vmscan: push lruvec pointer into isolate_lru_pages()
Move the mem_cgroup_zone_lruvec() call from isolate_lru_pages() into shrink_[in]active_list(). Further patches push it to shrink_zone() step by step. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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9e3b2f8cd3 |
mm/vmscan: store "priority" in struct scan_control
In memory reclaim some function have too many arguments - "priority" is one of them. It can be stored in struct scan_control - we construct them on the same level. Instead of an open coded loop we set the initial sc.priority, and do_try_to_free_pages() decreases it down to zero. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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3d58ab5c97 |
mm/memcg: use vm_swappiness from target memory cgroup
Use vm_swappiness from memory cgroup which is triggered this memory reclaim. This is more reasonable and allows to kill one argument. [akpm@linux-foundation.org: fix build (patch skew)] Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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89abfab133 |
mm/memcg: move reclaim_stat into lruvec
With mem_cgroup_disabled() now explicit, it becomes clear that the zone_reclaim_stat structure actually belongs in lruvec, per-zone when memcg is disabled but per-memcg per-zone when it's enabled. We can delete mem_cgroup_get_reclaim_stat(), and change update_page_reclaim_stat() to update just the one set of stats, the one which get_scan_count() will actually use. Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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c3c787e8c3 |
mm/memcg: scanning_global_lru means mem_cgroup_disabled
Although one has to admire the skill with which it has been concealed, scanning_global_lru(mz) is actually just an interesting way to test mem_cgroup_disabled(). Too many developer hours have been wasted on confusing it with global_reclaim(): just use mem_cgroup_disabled(). Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Glauber Costa <glommer@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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bbf808ed7d |
mm/memcg: kill mem_cgroup_lru_del()
This patch kills mem_cgroup_lru_del(), we can use mem_cgroup_lru_del_list() instead. On 0-order isolation we already have right lru list id. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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f3fd4a6192 |
mm: remove lru type checks from __isolate_lru_page()
After patch "mm: forbid lumpy-reclaim in shrink_active_list()" we can completely remove anon/file and active/inactive lru type filters from __isolate_lru_page(), because isolation for 0-order reclaim always isolates pages from right lru list. And pages-isolation for lumpy shrink_inactive_list() or memory-compaction anyway allowed to isolate pages from all evictable lru lists. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hughd@google.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Glauber Costa <glommer@parallels.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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3cb9945179 |
mm: push lru index into shrink_[in]active_list()
Let's toss lru index through call stack to isolate_lru_pages(), this is better than its reconstructing from individual bits. [akpm@linux-foundation.org: fix kerneldoc, per Minchan] Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Glauber Costa <glommer@parallels.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Satoru Moriya
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fe35004fbf |
mm: avoid swapping out with swappiness==0
Sometimes we'd like to avoid swapping out anonymous memory. In particular, avoid swapping out pages of important process or process groups while there is a reasonable amount of pagecache on RAM so that we can satisfy our customers' requirements. OTOH, we can control how aggressive the kernel will swap memory pages with /proc/sys/vm/swappiness for global and /sys/fs/cgroup/memory/memory.swappiness for each memcg. But with current reclaim implementation, the kernel may swap out even if we set swappiness=0 and there is pagecache in RAM. This patch changes the behavior with swappiness==0. If we set swappiness==0, the kernel does not swap out completely (for global reclaim until the amount of free pages and filebacked pages in a zone has been reduced to something very very small (nr_free + nr_filebacked < high watermark)). Signed-off-by: Satoru Moriya <satoru.moriya@hds.com> Acked-by: Minchan Kim <minchan@kernel.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Hocko
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e48982734e |
mm: consider all swapped back pages in used-once logic
Commit |
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Ying Han
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096a7cf447 |
mm: rename is_mlocked_vma() to mlocked_vma_newpage()
Andrew pointed out that the is_mlocked_vma() is misnamed. A function with name like that would expect bool return and no side-effects. Since it is called on the fault path for new page, rename it in this patch. Signed-off-by: Ying Han <yinghan@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com> Reviewed-by: Minchan Kim <minchan@kernel.org> [akpm@linux-foundation.org: s/mlock_vma_newpage/mlock_vma_newpage/, per Minchan] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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c3ac9a8ade |
mm: memcg: count pte references from every member of the reclaimed hierarchy
The rmap walker checking page table references has historically ignored references from VMAs that were not part of the memcg that was being reclaimed during memcg hard limit reclaim. When transitioning global reclaim to memcg hierarchy reclaim, I missed that bit and now references from outside a memcg are ignored even during global reclaim. Reverting back to traditional behaviour - count all references during global reclaim and only mind references of the memcg being reclaimed during limit reclaim would be one option. However, the more generic idea is to ignore references exactly then when they are outside the hierarchy that is currently under reclaim; because only then will their reclamation be of any use to help the pressure situation. It makes no sense to ignore references from a sibling memcg and then evict a page that will be immediately refaulted by that sibling which contributes to the same usage of the common ancestor under reclaim. The solution: make the rmap walker ignore references from VMAs that are not part of the hierarchy that is being reclaimed. Flat limit reclaim will stay the same, hierarchical limit reclaim will mind the references only to pages that the hierarchy owns. Global reclaim, since it reclaims from all memcgs, will be fixed to regard all references. [akpm@linux-foundation.org: name the args in the declaration] Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: Konstantin Khlebnikov<khlebnikov@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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23b9da55c5 |
mm: vmscan: remove reclaim_mode_t
There is little motiviation for reclaim_mode_t once RECLAIM_MODE_[A]SYNC and lumpy reclaim have been removed. This patch gets rid of reclaim_mode_t as well and improves the documentation about what reclaim/compaction is and when it is triggered. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Hugh Dickins <hughd@google.com> Cc: Ying Han <yinghan@google.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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41ac1999c3 |
mm: vmscan: do not stall on writeback during memory compaction
This patch stops reclaim/compaction entering sync reclaim as this was only intended for lumpy reclaim and an oversight. Page migration has its own logic for stalling on writeback pages if necessary and memory compaction is already using it. Waiting on page writeback is bad for a number of reasons but the primary one is that waiting on writeback to a slow device like USB can take a considerable length of time. Page reclaim instead uses wait_iff_congested() to throttle if too many dirty pages are being scanned. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Hugh Dickins <hughd@google.com> Cc: Ying Han <yinghan@google.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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c53919adc0 |
mm: vmscan: remove lumpy reclaim
This series removes lumpy reclaim and some stalling logic that was
unintentionally being used by memory compaction. The end result is that
stalling on dirty pages during page reclaim now depends on
wait_iff_congested().
Four kernels were compared
3.3.0 vanilla
3.4.0-rc2 vanilla
3.4.0-rc2 lumpyremove-v2 is patch one from this series
3.4.0-rc2 nosync-v2r3 is the full series
Removing lumpy reclaim saves almost 900 bytes of text whereas the full
series removes 1200 bytes.
text data bss dec hex filename
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Rik van Riel
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e709ffd616 |
mm: remove swap token code
The swap token code no longer fits in with the current VM model. It does not play well with cgroups or the better NUMA placement code in development, since we have only one swap token globally. It also has the potential to mess with scalability of the system, by increasing the number of non-reclaimable pages on the active and inactive anon LRU lists. Last but not least, the swap token code has been broken for a year without complaints, as reported by Konstantin Khlebnikov. This suggests we no longer have much use for it. The days of sub-1G memory systems with heavy use of swap are over. If we ever need thrashing reducing code in the future, we will have to implement something that does scale. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Konstantin Khlebnikov <khlebnikov@openvz.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Hugh Dickins <hughd@google.com> Acked-by: Bob Picco <bpicco@meloft.net> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ying Han
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904249aa68 |
mm: fix up the vmscan stat in vmstat
The "pgsteal" stat is confusing because it counts both direct reclaim as well as background reclaim. However, we have "kswapd_steal" which also counts background reclaim value. This patch fixes it and also makes it match the existng "pgscan_" stats. Test: pgsteal_kswapd_dma32 447623 pgsteal_kswapd_normal 42272677 pgsteal_kswapd_movable 0 pgsteal_direct_dma32 2801 pgsteal_direct_normal 44353270 pgsteal_direct_movable 0 Signed-off-by: Ying Han <yinghan@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Christoph Lameter <cl@linux.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mel@csn.ul.ie> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dan Magenheimer <dan.magenheimer@oracle.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ying Han
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41c9308812 |
Revert "mm: vmscan: fix misused nr_reclaimed in shrink_mem_cgroup_zone()"
This reverts commit
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Rik van Riel
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496b919b3b |
Fix potential endless loop in kswapd when compaction is not enabled
We should only test compaction_suitable if the kernel is built with CONFIG_COMPACTION, otherwise the stub compaction_suitable function will always return COMPACT_SKIPPED and send kswapd into an infinite loop. Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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643ac9fc54 |
mm: fix testorder interaction between two kswapd patches
Adjusting |
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Konstantin Khlebnikov
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1480de0340 |
mm: forbid lumpy-reclaim in shrink_active_list()
Reset the reclaim mode in shrink_active_list() to RECLAIM_MODE_SINGLE | RECLAIM_MODE_ASYNC. (sync/async sign is used only in shrink_page_list and does not affect shrink_active_list) Currenly shrink_active_list() sometimes works in lumpy-reclaim mode, if RECLAIM_MODE_LUMPYRECLAIM is left over from an earlier shrink_inactive_list(). Meanwhile, in age_active_anon() sc->reclaim_mode is totally zero. So the current behavior is too complex and confusing, and this looks like bug. In general, shrink_active_list() populates the inactive list for the next shrink_inactive_list(). Lumpy shring_inactive_list() isolates pages around the chosen one from both the active and inactive lists. So, there is no reason for lumpy isolation in shrink_active_list(). See also: https://lkml.org/lkml/2012/3/15/583 Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Proposed-by: Hugh Dickins <hughd@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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cc9a6c8776 |
cpuset: mm: reduce large amounts of memory barrier related damage v3
Commit
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Copot Alexandru
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c7cfa37b73 |
mm/vmscan.c: fix spelling error
s/noticable/noticeable/ Signed-off-by: Copot Alexandru <alex.mihai.c@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hillf Danton
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d563c0501b |
vmscan: handle isolated pages with lru lock released
When shrinking inactive lru list, isolated pages are queued on locally private list, so the lock-hold time could be reduced if pages are counted without lock protection. To achieve that, firstly updating reclaim stat is delayed until the putback stage, after reacquiring the lru lock. Secondly, operations related to vm and zone stats are now proteced with preemption disabled as they are per-cpu operations. Signed-off-by: Hillf Danton <dhillf@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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cc715d99e5 |
mm: vmscan: forcibly scan highmem if there are too many buffer_heads pinning highmem
Stuart Foster reported on bugzilla that copying large amounts of data from NTFS caused an OOM kill on 32-bit X86 with 16G of memory. Andrew Morton correctly identified that the problem was NTFS was using 512 blocks meaning each page had 8 buffer_heads in low memory pinning it. In the past, direct reclaim used to scan highmem even if the allocating process did not specify __GFP_HIGHMEM but not any more. kswapd no longer will reclaim from zones that are above the high watermark. The intention in both cases was to minimise unnecessary reclaim. The downside is on machines with large amounts of highmem that lowmem can be fully consumed by buffer_heads with nothing trying to free them. The following patch is based on a suggestion by Andrew Morton to extend the buffer_heads_over_limit case to force kswapd and direct reclaim to scan the highmem zone regardless of the allocation request or watermarks. Addresses https://bugzilla.kernel.org/show_bug.cgi?id=42578 [hughd@google.com: move buffer_heads_over_limit check up] [akpm@linux-foundation.org: buffer_heads_over_limit is unlikely] Reported-by: Stuart Foster <smf.linux@ntlworld.com> Tested-by: Stuart Foster <smf.linux@ntlworld.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Christoph Lameter <cl@linux.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rik van Riel
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aff622495c |
vmscan: only defer compaction for failed order and higher
Currently a failed order-9 (transparent hugepage) compaction can lead to memory compaction being temporarily disabled for a memory zone. Even if we only need compaction for an order 2 allocation, eg. for jumbo frames networking. The fix is relatively straightforward: keep track of the highest order at which compaction is succeeding, and only defer compaction for orders at which compaction is failing. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rik van Riel
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7be62de99a |
vmscan: kswapd carefully call compaction
With CONFIG_COMPACTION enabled, kswapd does not try to free contiguous free pages, even when it is woken for a higher order request. This could be bad for eg. jumbo frame network allocations, which are done from interrupt context and cannot compact memory themselves. Higher than before allocation failure rates in the network receive path have been observed in kernels with compaction enabled. Teach kswapd to defragment the memory zones in a node, but only if required and compaction is not deferred in a zone. [akpm@linux-foundation.org: reduce scope of zones_need_compaction] Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rik van Riel
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fe2c2a1066 |
vmscan: reclaim at order 0 when compaction is enabled
When built with CONFIG_COMPACTION, kswapd should not try to free contiguous pages, because it is not trying hard enough to have a real chance at being successful, but still disrupts the LRU enough to break other things. Do not do higher order page isolation unless we really are in lumpy reclaim mode. Stop reclaiming pages once we have enough free pages that compaction can deal with things, and we hit the normal order 0 watermarks used by kswapd. Also remove a line of code that increments balanced right before exiting the function. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hillf Danton
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c38446cc65 |
mm: vmscan: fix misused nr_reclaimed in shrink_mem_cgroup_zone()
The value of nr_reclaimed is the number of pages reclaimed in the current round of the loop, whereas nr_to_reclaim should be compared with the number of pages reclaimed in all rounds. In each round of the loop, reclaimed pages are cut off from the reclaim goal, and the loop stops once the goal achieved. Signed-off-by: Hillf Danton <dhillf@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hillf Danton
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6131728914 |
mm/vmscan.c: cleanup with s/reclaim_mode/isolate_mode/
With tons of reclaim_mode (defined as one field of struct scan_control) already in the file, it is clearer to rename the local reclaim_mode when setting up the isolation mode. Signed-off-by: Hillf Danton <dhillf@gmail.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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245132643e |
SHM_UNLOCK: fix Unevictable pages stranded after swap
Commit
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Hugh Dickins
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85046579bd |
SHM_UNLOCK: fix long unpreemptible section
scan_mapping_unevictable_pages() is used to make SysV SHM_LOCKed pages evictable again once the shared memory is unlocked. It does this with pagevec_lookup()s across the whole object (which might occupy most of memory), and takes 300ms to unlock 7GB here. A cond_resched() every PAGEVEC_SIZE pages would be good. However, KOSAKI-san points out that this is called under shmem.c's info->lock, and it's also under shm.c's shm_lock(), both spinlocks. There is no strong reason for that: we need to take these pages off the unevictable list soonish, but those locks are not required for it. So move the call to scan_mapping_unevictable_pages() from shmem.c's unlock handling up to shm.c's unlock handling. Remove the recently added barrier, not needed now we have spin_unlock() before the scan. Use get_file(), with subsequent fput(), to make sure we have a reference to mapping throughout scan_mapping_unevictable_pages(): that's something that was previously guaranteed by the shm_lock(). Remove shmctl's lru_add_drain_all(): we don't fault in pages at SHM_LOCK time, and we lazily discover them to be Unevictable later, so it serves no purpose for SHM_LOCK; and serves no purpose for SHM_UNLOCK, since pages still on pagevec are not marked Unevictable. The original code avoided redundant rescans by checking VM_LOCKED flag at its level: now avoid them by checking shp's SHM_LOCKED. The original code called scan_mapping_unevictable_pages() on a locked area at shm_destroy() time: perhaps we once had accounting cross-checks which required that, but not now, so skip the overhead and just let inode eviction deal with them. Put check_move_unevictable_page() and scan_mapping_unevictable_pages() under CONFIG_SHMEM (with stub for the TINY case when ramfs is used), more as comment than to save space; comment them used for SHM_UNLOCK. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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3f79768f23 |
mm: rearrange putback_inactive_pages
There is sometimes confusion between the global putback_lru_pages() in migrate.c and the static putback_lru_pages() in vmscan.c: rename the latter putback_inactive_pages(): it helps shrink_inactive_list() rather as move_active_pages_to_lru() helps shrink_active_list(). Remove unused scan_control arg from putback_inactive_pages() and from update_isolated_counts(). Move clear_active_flags() inside update_isolated_counts(). Move NR_ISOLATED accounting up into shrink_inactive_list() itself, so the balance is clearer. Do the spin_lock_irq() before calling putback_inactive_pages() and spin_unlock_irq() after return from it, so that it better matches update_isolated_counts() and move_active_pages_to_lru(). Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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f626012db0 |
mm: remove isolate_pages()
The isolate_pages() level in vmscan.c offers little but indirection: merge it into isolate_lru_pages() as the compiler does, and use the names nr_to_scan and nr_scanned in each case. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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4111304dab |
mm: enum lru_list lru
Mostly we use "enum lru_list lru": change those few "l"s to "lru"s. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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2bcf887963 |
mm: take pagevecs off reclaim stack
Replace pagevecs in putback_lru_pages() and move_active_pages_to_lru() by lists of pages_to_free: then apply Konstantin Khlebnikov's free_hot_cold_page_list() to them instead of pagevec_release(). Which simplifies the flow (no need to drop and retake lock whenever pagevec fills up) and reduces stale addresses in stack backtraces (which often showed through the pagevecs); but more importantly, removes another 120 bytes from the deepest stacks in page reclaim. Although I've not recently seen an actual stack overflow here with a vanilla kernel, move_active_pages_to_lru() has often featured in deep backtraces. However, free_hot_cold_page_list() does not handle compound pages (nor need it: a Transparent HugePage would have been split by the time it reaches the call in shrink_page_list()), but it is possible for putback_lru_pages() or move_active_pages_to_lru() to be left holding the last reference on a THP, so must exclude the unlikely compound case before putting on pages_to_free. Remove pagevec_strip(), its work now done in move_active_pages_to_lru(). The pagevec in scan_mapping_unevictable_pages() remains in mm/vmscan.c, but that is never on the reclaim path, and cannot be replaced by a list. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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0cee34fd72 |
mm: vmscan: check if reclaim should really abort even if compaction_ready() is true for one zone
If compaction can proceed for a given zone, shrink_zones() does not reclaim any more pages from it. After commit [e0c2327: vmscan: abort reclaim/compaction if compaction can proceed], do_try_to_free_pages() tries to finish as soon as possible once one zone can compact. This was intended to prevent slabs being shrunk unnecessarily but there are side-effects. One is that a small zone that is ready for compaction will abort reclaim even if the chances of successfully allocating a THP from that zone is small. It also means that reclaim can return too early even though sc->nr_to_reclaim pages were not reclaimed. This partially reverts the commit until it is proven that slabs are really being shrunk unnecessarily but preserves the check to return 1 to avoid OOM if reclaim was aborted prematurely. [aarcange@redhat.com: This patch replaces a revert from Andrea] Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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fe4b1b244b |
mm: vmscan: when reclaiming for compaction, ensure there are sufficient free pages available
In commit
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Mel Gorman
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c824493528 |
mm: compaction: make isolate_lru_page() filter-aware again
Commit
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Mel Gorman
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7335084d44 |
mm: vmscan: do not OOM if aborting reclaim to start compaction
During direct reclaim it is possible that reclaim will be aborted so that compaction can be attempted to satisfy a high-order allocation. If this decision is made before any pages are reclaimed, it is possible that 0 is returned to the page allocator potentially triggering an OOM. This has not been observed but it is a possibility so this patch addresses it. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andrea Arcangeli
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5013473152 |
mm: vmscan: check if we isolated a compound page during lumpy scan
Properly take into account if we isolated a compound page during the lumpy scan in reclaim and skip over the tail pages when encountered. This corrects the values given to the tracepoint for number of lumpy pages isolated and will avoid breaking the loop early if compound pages smaller than the requested allocation size are requested. [mgorman@suse.de: Updated changelog] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Tao Ma
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ea4d349ffa |
vmscan/trace: Add 'file' info to trace_mm_vmscan_lru_isolate()
In trace_mm_vmscan_lru_isolate(), we don't output 'file' information to the trace event and it is a bit inconvenient for the user to get the real information(like pasted below). mm_vmscan_lru_isolate: isolate_mode=2 order=0 nr_requested=32 nr_scanned=32 nr_taken=32 contig_taken=0 contig_dirty=0 contig_failed=0 'active' can be obtained by analyzing mode(Thanks go to Minchan and Mel), So this patch adds 'file' to the trace event and it now looks like: mm_vmscan_lru_isolate: isolate_mode=2 order=0 nr_requested=32 nr_scanned=32 nr_taken=32 contig_taken=0 contig_dirty=0 contig_failed=0 file=0 Signed-off-by: Tao Ma <boyu.mt@taobao.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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72835c86ca |
mm: unify remaining mem_cont, mem, etc. variable names to memcg
Signed-off-by: Johannes Weiner <jweiner@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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925b7673cc |
mm: make per-memcg LRU lists exclusive
Now that all code that operated on global per-zone LRU lists is converted to operate on per-memory cgroup LRU lists instead, there is no reason to keep the double-LRU scheme around any longer. The pc->lru member is removed and page->lru is linked directly to the per-memory cgroup LRU lists, which removes two pointers from a descriptor that exists for every page frame in the system. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Ying Han <yinghan@google.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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6290df5458 |
mm: collect LRU list heads into struct lruvec
Having a unified structure with a LRU list set for both global zones and per-memcg zones allows to keep that code simple which deals with LRU lists and does not care about the container itself. Once the per-memcg LRU lists directly link struct pages, the isolation function and all other list manipulations are shared between the memcg case and the global LRU case. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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b95a2f2d48 |
mm: vmscan: convert global reclaim to per-memcg LRU lists
The global per-zone LRU lists are about to go away on memcg-enabled kernels, global reclaim must be able to find its pages on the per-memcg LRU lists. Since the LRU pages of a zone are distributed over all existing memory cgroups, a scan target for a zone is complete when all memory cgroups are scanned for their proportional share of a zone's memory. The forced scanning of small scan targets from kswapd is limited to zones marked unreclaimable, otherwise kswapd can quickly overreclaim by force-scanning the LRU lists of multiple memory cgroups. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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5660048cca |
mm: move memcg hierarchy reclaim to generic reclaim code
Memory cgroup limit reclaim and traditional global pressure reclaim will soon share the same code to reclaim from a hierarchical tree of memory cgroups. In preparation of this, move the two right next to each other in shrink_zone(). The mem_cgroup_hierarchical_reclaim() polymath is split into a soft limit reclaim function, which still does hierarchy walking on its own, and a limit (shrinking) reclaim function, which relies on generic reclaim code to walk the hierarchy. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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f16015fbf2 |
mm: vmscan: distinguish between memcg triggering reclaim and memcg being scanned
Memory cgroup hierarchies are currently handled completely outside of the traditional reclaim code, which is invoked with a single memory cgroup as an argument for the whole call stack. Subsequent patches will switch this code to do hierarchical reclaim, so there needs to be a distinction between a) the memory cgroup that is triggering reclaim due to hitting its limit and b) the memory cgroup that is being scanned as a child of a). This patch introduces a struct mem_cgroup_zone that contains the combination of the memory cgroup and the zone being scanned, which is then passed down the stack instead of the zone argument. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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89b5fae536 |
mm: vmscan: distinguish global reclaim from global LRU scanning
The traditional zone reclaim code is scanning the per-zone LRU lists during direct reclaim and kswapd, and the per-zone per-memory cgroup LRU lists when reclaiming on behalf of a memory cgroup limit. Subsequent patches will convert the traditional reclaim code to reclaim exclusively from the per-memory cgroup LRU lists. As a result, using the predicate for which LRU list is scanned will no longer be appropriate to tell global reclaim from limit reclaim. This patch adds a global_reclaim() predicate to tell direct/kswapd reclaim from memory cgroup limit reclaim and substitutes it in all places where currently scanning_global_lru() is used for that. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hillf Danton
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3770490ec8 |
mm: vmscan: fix typo in isolating lru pages
It is not the tag page but the cursor page that we should process, and it looks a typo. Signed-off-by: Hillf Danton <dhillf@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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043bcbe5ec |
mm: test PageSwapBacked in lumpy reclaim
Lumpy reclaim does well to stop at a PageAnon when there's no swap, but better is to stop at any PageSwapBacked, which includes shmem/tmpfs too. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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86cfd3a450 |
mm/vmscan.c: consider swap space when deciding whether to continue reclaim
It's pointless to continue reclaiming when we have no swap space and lots of anon pages in the inactive list. Without this patch, it is possible when swap is disabled to continue trying to reclaim when there are only anonymous pages in the system even though that will not make any progress. Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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KOSAKI Motohiro
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25bd91bd27 |
vmscan: add task name to warn_scan_unevictable() messages
If we need to know a usecase, caller program name is critical important. Show it. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> David Rientjes <rientjes@google.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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cc59850ef9 |
mm: add free_hot_cold_page_list() helper
This patch adds helper free_hot_cold_page_list() to free list of 0-order pages. It frees pages directly from list without temporary page-vector. It also calls trace_mm_pagevec_free() to simulate pagevec_free() behaviour. bloat-o-meter: add/remove: 1/1 grow/shrink: 1/3 up/down: 267/-295 (-28) function old new delta free_hot_cold_page_list - 264 +264 get_page_from_freelist 2129 2132 +3 __pagevec_free 243 239 -4 split_free_page 380 373 -7 release_pages 606 510 -96 free_page_list 188 - -188 Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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c909e99364 |
vmscan: activate executable pages after first usage
Logic added in commit |
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Konstantin Khlebnikov
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34dbc67a64 |
vmscan: promote shared file mapped pages
Commit |
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Greg Kroah-Hartman
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ff4b8a57f0 |
Merge branch 'driver-core-next' into Linux 3.2
This resolves the conflict in the arch/arm/mach-s3c64xx/s3c6400.c file, and it fixes the build error in the arch/x86/kernel/microcode_core.c file, that the merge did not catch. The microcode_core.c patch was provided by Stephen Rothwell <sfr@canb.auug.org.au> who was invaluable in the merge issues involved with the large sysdev removal process in the driver-core tree. Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
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Kay Sievers
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10fbcf4c6c |
convert 'memory' sysdev_class to a regular subsystem
This moves the 'memory sysdev_class' over to a regular 'memory' subsystem and converts the devices to regular devices. The sysdev drivers are implemented as subsystem interfaces now. After all sysdev classes are ported to regular driver core entities, the sysdev implementation will be entirely removed from the kernel. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
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Konstantin Khlebnikov
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83aeeada7c |
vmscan: use atomic-long for shrinker batching
Use atomic-long operations instead of looping around cmpxchg(). [akpm@linux-foundation.org: massage atomic.h inclusions] Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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635697c663 |
vmscan: fix initial shrinker size handling
A shrinker function can return -1, means that it cannot do anything without a risk of deadlock. For example prune_super() does this if it cannot grab a superblock refrence, even if nr_to_scan=0. Currently we interpret this -1 as a ULONG_MAX size shrinker and evaluate `total_scan' according to this. So the next time around this shrinker can cause really big pressure. Let's skip such shrinkers instead. Also make total_scan signed, otherwise the check (total_scan < 0) below never works. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Dave Chinner <david@fromorbit.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
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208bca0860 |
Merge branch 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
* 'writeback-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux: writeback: Add a 'reason' to wb_writeback_work writeback: send work item to queue_io, move_expired_inodes writeback: trace event balance_dirty_pages writeback: trace event bdi_dirty_ratelimit writeback: fix ppc compile warnings on do_div(long long, unsigned long) writeback: per-bdi background threshold writeback: dirty position control - bdi reserve area writeback: control dirty pause time writeback: limit max dirty pause time writeback: IO-less balance_dirty_pages() writeback: per task dirty rate limit writeback: stabilize bdi->dirty_ratelimit writeback: dirty rate control writeback: add bg_threshold parameter to __bdi_update_bandwidth() writeback: dirty position control writeback: account per-bdi accumulated dirtied pages |
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Johannes Weiner
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9b272977e3 |
memcg: skip scanning active lists based on individual size
Reclaim decides to skip scanning an active list when the corresponding inactive list is above a certain size in comparison to leave the assumed working set alone while there are still enough reclaim candidates around. The memcg implementation of comparing those lists instead reports whether the whole memcg is low on the requested type of inactive pages, considering all nodes and zones. This can lead to an oversized active list not being scanned because of the state of the other lists in the memcg, as well as an active list being scanned while its corresponding inactive list has enough pages. Not only is this wrong, it's also a scalability hazard, because the global memory state over all nodes and zones has to be gathered for each memcg and zone scanned. Make these calculations purely based on the size of the two LRU lists that are actually affected by the outcome of the decision. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Ying Han <yinghan@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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e0c23279c9 |
vmscan: abort reclaim/compaction if compaction can proceed
If compaction can proceed, shrink_zones() stops doing any work but its callers still call shrink_slab() which raises the priority and potentially sleeps. This is unnecessary and wasteful so this patch aborts direct reclaim/compaction entirely if compaction can proceed. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <jweiner@redhat.com> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rik van Riel
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e0887c19b2 |
vmscan: limit direct reclaim for higher order allocations
When suffering from memory fragmentation due to unfreeable pages, THP page faults will repeatedly try to compact memory. Due to the unfreeable pages, compaction fails. Needless to say, at that point page reclaim also fails to create free contiguous 2MB areas. However, that doesn't stop the current code from trying, over and over again, and freeing a minimum of 4MB (2UL << sc->order pages) at every single invocation. This resulted in my 12GB system having 2-3GB free memory, a corresponding amount of used swap and very sluggish response times. This can be avoided by having the direct reclaim code not reclaim from zones that already have plenty of free memory available for compaction. If compaction still fails due to unmovable memory, doing additional reclaim will only hurt the system, not help. [jweiner@redhat.com: change comment to explain the order check] Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Johannes Weiner <jweiner@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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21ee9f398b |
vmscan: add barrier to prevent evictable page in unevictable list
When a race between putback_lru_page() and shmem_lock with lock=0 happens, progrom execution order is as follows, but clear_bit in processor #1 could be reordered right before spin_unlock of processor #1. Then, the page would be stranded on the unevictable list. spin_lock SetPageLRU spin_unlock clear_bit(AS_UNEVICTABLE) spin_lock if PageLRU() if !test_bit(AS_UNEVICTABLE) move evictable list smp_mb if !test_bit(AS_UNEVICTABLE) move evictable list spin_unlock But, pagevec_lookup() in scan_mapping_unevictable_pages() has rcu_read_[un]lock() so it could protect reordering before reaching test_bit(AS_UNEVICTABLE) on processor #1 so this problem never happens. But it's a unexpected side effect and we should solve this problem properly. This patch adds a barrier after mapping_clear_unevictable. I didn't meet this problem but just found during review. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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264e56d824 |
mm: disable user interface to manually rescue unevictable pages
At one point, anonymous pages were supposed to go on the unevictable list when no swap space was configured, and the idea was to manually rescue those pages after adding swap and making them evictable again. But nowadays, swap-backed pages on the anon LRU list are not scanned without available swap space anyway, so there is no point in moving them to a separate list anymore. The manual rescue could also be used in case pages were stranded on the unevictable list due to race conditions. But the code has been around for a while now and newly discovered bugs should be properly reported and dealt with instead of relying on such a manual fixup. In addition to the lack of a usecase, the sysfs interface to rescue pages from a specific NUMA node has been broken since its introduction, so it's unlikely that anybody ever relied on that. This patch removes the functionality behind the sysctl and the node-interface and emits a one-time warning when somebody tries to access either of them. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reported-by: Kautuk Consul <consul.kautuk@gmail.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Kautuk Consul
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3f380998ae |
vmscan.c: fix invalid strict_strtoul() check in write_scan_unevictable_node()
write_scan_unevictable_node() checks the value req returned by strict_strtoul() and returns 1 if req is 0. However, when strict_strtoul() returns 0, it means successful conversion of buf to unsigned long. Due to this, the function was not proceeding to scan the zones for unevictable pages even though we write a valid value to the scan_unevictable_pages sys file. Change this check slightly to check for invalid value in buf as well as 0 value stored in res after successful conversion via strict_strtoul. In both cases, we do not perform the scanning of this node's zones. Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Alex,Shi
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f0dfcde099 |
kswapd: assign new_order and new_classzone_idx after wakeup in sleeping
There 2 places to read pgdat in kswapd. One is return from a successful balance, another is waked up from kswapd sleeping. The new_order and new_classzone_idx represent the balance input order and classzone_idx. But current new_order and new_classzone_idx are not assigned after kswapd_try_to_sleep(), that will cause a bug in the following scenario. 1: after a successful balance, kswapd goes to sleep, and new_order = 0; new_classzone_idx = __MAX_NR_ZONES - 1; 2: kswapd waked up with order = 3 and classzone_idx = ZONE_NORMAL 3: in the balance_pgdat() running, a new balance wakeup happened with order = 5, and classzone_idx = ZONE_NORMAL 4: the first wakeup(order = 3) finished successufly, return order = 3 but, the new_order is still 0, so, this balancing will be treated as a failed balance. And then the second tighter balancing will be missed. So, to avoid the above problem, the new_order and new_classzone_idx need to be assigned for later successful comparison. Signed-off-by: Alex Shi <alex.shi@intel.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Tested-by: Pádraig Brady <P@draigBrady.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Alex,Shi
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d2ebd0f6b8 |
kswapd: avoid unnecessary rebalance after an unsuccessful balancing
In commit
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Shaohua Li
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16fb951237 |
vmscan: count pages into balanced for zone with good watermark
It's possible a zone watermark is ok when entering the balance_pgdat() loop, while the zone is within the requested classzone_idx. Count pages from this zone into `balanced'. In this way, we can skip shrinking zones too much for high order allocation. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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49ea7eb65e |
mm: vmscan: immediately reclaim end-of-LRU dirty pages when writeback completes
When direct reclaim encounters a dirty page, it gets recycled around the LRU for another cycle. This patch marks the page PageReclaim similar to deactivate_page() so that the page gets reclaimed almost immediately after the page gets cleaned. This is to avoid reclaiming clean pages that are younger than a dirty page encountered at the end of the LRU that might have been something like a use-once page. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <jweiner@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Alex Elder <aelder@sgi.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <chris.mason@oracle.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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92df3a723f |
mm: vmscan: throttle reclaim if encountering too many dirty pages under writeback
Workloads that are allocating frequently and writing files place a large number of dirty pages on the LRU. With use-once logic, it is possible for them to reach the end of the LRU quickly requiring the reclaimer to scan more to find clean pages. Ordinarily, processes that are dirtying memory will get throttled by dirty balancing but this is a global heuristic and does not take into account that LRUs are maintained on a per-zone basis. This can lead to a situation whereby reclaim is scanning heavily, skipping over a large number of pages under writeback and recycling them around the LRU consuming CPU. This patch checks how many of the number of pages isolated from the LRU were dirty and under writeback. If a percentage of them under writeback, the process will be throttled if a backing device or the zone is congested. Note that this applies whether it is anonymous or file-backed pages that are under writeback meaning that swapping is potentially throttled. This is intentional due to the fact if the swap device is congested, scanning more pages and dispatching more IO is not going to help matters. The percentage that must be in writeback depends on the priority. At default priority, all of them must be dirty. At DEF_PRIORITY-1, 50% of them must be, DEF_PRIORITY-2, 25% etc. i.e. as pressure increases the greater the likelihood the process will get throttled to allow the flusher threads to make some progress. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <jweiner@redhat.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Alex Elder <aelder@sgi.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <chris.mason@oracle.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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f84f6e2b08 |
mm: vmscan: do not writeback filesystem pages in kswapd except in high priority
It is preferable that no dirty pages are dispatched for cleaning from the page reclaim path. At normal priorities, this patch prevents kswapd writing pages. However, page reclaim does have a requirement that pages be freed in a particular zone. If it is failing to make sufficient progress (reclaiming < SWAP_CLUSTER_MAX at any priority priority), the priority is raised to scan more pages. A priority of DEF_PRIORITY - 3 is considered to be the point where kswapd is getting into trouble reclaiming pages. If this priority is reached, kswapd will dispatch pages for writing. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Alex Elder <aelder@sgi.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <chris.mason@oracle.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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a18bba061c |
mm: vmscan: remove dead code related to lumpy reclaim waiting on pages under writeback
Lumpy reclaim worked with two passes - the first which queued pages for IO and the second which waited on writeback. As direct reclaim can no longer write pages there is some dead code. This patch removes it but direct reclaim will continue to wait on pages under writeback while in synchronous reclaim mode. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Alex Elder <aelder@sgi.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <chris.mason@oracle.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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ee72886d8e |
mm: vmscan: do not writeback filesystem pages in direct reclaim
Testing from the XFS folk revealed that there is still too much I/O from the end of the LRU in kswapd. Previously it was considered acceptable by VM people for a small number of pages to be written back from reclaim with testing generally showing about 0.3% of pages reclaimed were written back (higher if memory was low). That writing back a small number of pages is ok has been heavily disputed for quite some time and Dave Chinner explained it well; It doesn't have to be a very high number to be a problem. IO is orders of magnitude slower than the CPU time it takes to flush a page, so the cost of making a bad flush decision is very high. And single page writeback from the LRU is almost always a bad flush decision. To complicate matters, filesystems respond very differently to requests from reclaim according to Christoph Hellwig; xfs tries to write it back if the requester is kswapd ext4 ignores the request if it's a delayed allocation btrfs ignores the request As a result, each filesystem has different performance characteristics when under memory pressure and there are many pages being dirtied. In some cases, the request is ignored entirely so the VM cannot depend on the IO being dispatched. The objective of this series is to reduce writing of filesystem-backed pages from reclaim, play nicely with writeback that is already in progress and throttle reclaim appropriately when writeback pages are encountered. The assumption is that the flushers will always write pages faster than if reclaim issues the IO. A secondary goal is to avoid the problem whereby direct reclaim splices two potentially deep call stacks together. There is a potential new problem as reclaim has less control over how long before a page in a particularly zone or container is cleaned and direct reclaimers depend on kswapd or flusher threads to do the necessary work. However, as filesystems sometimes ignore direct reclaim requests already, it is not expected to be a serious issue. Patch 1 disables writeback of filesystem pages from direct reclaim entirely. Anonymous pages are still written. Patch 2 removes dead code in lumpy reclaim as it is no longer able to synchronously write pages. This hurts lumpy reclaim but there is an expectation that compaction is used for hugepage allocations these days and lumpy reclaim's days are numbered. Patches 3-4 add warnings to XFS and ext4 if called from direct reclaim. With patch 1, this "never happens" and is intended to catch regressions in this logic in the future. Patch 5 disables writeback of filesystem pages from kswapd unless the priority is raised to the point where kswapd is considered to be in trouble. Patch 6 throttles reclaimers if too many dirty pages are being encountered and the zones or backing devices are congested. Patch 7 invalidates dirty pages found at the end of the LRU so they are reclaimed quickly after being written back rather than waiting for a reclaimer to find them I consider this series to be orthogonal to the writeback work but it is worth noting that the writeback work affects the viability of patch 8 in particular. I tested this on ext4 and xfs using fs_mark, a simple writeback test based on dd and a micro benchmark that does a streaming write to a large mapping (exercises use-once LRU logic) followed by streaming writes to a mix of anonymous and file-backed mappings. The command line for fs_mark when botted with 512M looked something like ./fs_mark -d /tmp/fsmark-2676 -D 100 -N 150 -n 150 -L 25 -t 1 -S0 -s 10485760 The number of files was adjusted depending on the amount of available memory so that the files created was about 3xRAM. For multiple threads, the -d switch is specified multiple times. The test machine is x86-64 with an older generation of AMD processor with 4 cores. The underlying storage was 4 disks configured as RAID-0 as this was the best configuration of storage I had available. Swap is on a separate disk. Dirty ratio was tuned to 40% instead of the default of 20%. Testing was run with and without monitors to both verify that the patches were operating as expected and that any performance gain was real and not due to interference from monitors. Here is a summary of results based on testing XFS. 512M1P-xfs Files/s mean 32.69 ( 0.00%) 34.44 ( 5.08%) 512M1P-xfs Elapsed Time fsmark 51.41 48.29 512M1P-xfs Elapsed Time simple-wb 114.09 108.61 512M1P-xfs Elapsed Time mmap-strm 113.46 109.34 512M1P-xfs Kswapd efficiency fsmark 62% 63% 512M1P-xfs Kswapd efficiency simple-wb 56% 61% 512M1P-xfs Kswapd efficiency mmap-strm 44% 42% 512M-xfs Files/s mean 30.78 ( 0.00%) 35.94 (14.36%) 512M-xfs Elapsed Time fsmark 56.08 48.90 512M-xfs Elapsed Time simple-wb 112.22 98.13 512M-xfs Elapsed Time mmap-strm 219.15 196.67 512M-xfs Kswapd efficiency fsmark 54% 56% 512M-xfs Kswapd efficiency simple-wb 54% 55% 512M-xfs Kswapd efficiency mmap-strm 45% 44% 512M-4X-xfs Files/s mean 30.31 ( 0.00%) 33.33 ( 9.06%) 512M-4X-xfs Elapsed Time fsmark 63.26 55.88 512M-4X-xfs Elapsed Time simple-wb 100.90 90.25 512M-4X-xfs Elapsed Time mmap-strm 261.73 255.38 512M-4X-xfs Kswapd efficiency fsmark 49% 50% 512M-4X-xfs Kswapd efficiency simple-wb 54% 56% 512M-4X-xfs Kswapd efficiency mmap-strm 37% 36% 512M-16X-xfs Files/s mean 60.89 ( 0.00%) 65.22 ( 6.64%) 512M-16X-xfs Elapsed Time fsmark 67.47 58.25 512M-16X-xfs Elapsed Time simple-wb 103.22 90.89 512M-16X-xfs Elapsed Time mmap-strm 237.09 198.82 512M-16X-xfs Kswapd efficiency fsmark 45% 46% 512M-16X-xfs Kswapd efficiency simple-wb 53% 55% 512M-16X-xfs Kswapd efficiency mmap-strm 33% 33% Up until 512-4X, the FSmark improvements were statistically significant. For the 4X and 16X tests the results were within standard deviations but just barely. The time to completion for all tests is improved which is an important result. In general, kswapd efficiency is not affected by skipping dirty pages. 1024M1P-xfs Files/s mean 39.09 ( 0.00%) 41.15 ( 5.01%) 1024M1P-xfs Elapsed Time fsmark 84.14 80.41 1024M1P-xfs Elapsed Time simple-wb 210.77 184.78 1024M1P-xfs Elapsed Time mmap-strm 162.00 160.34 1024M1P-xfs Kswapd efficiency fsmark 69% 75% 1024M1P-xfs Kswapd efficiency simple-wb 71% 77% 1024M1P-xfs Kswapd efficiency mmap-strm 43% 44% 1024M-xfs Files/s mean 35.45 ( 0.00%) 37.00 ( 4.19%) 1024M-xfs Elapsed Time fsmark 94.59 91.00 1024M-xfs Elapsed Time simple-wb 229.84 195.08 1024M-xfs Elapsed Time mmap-strm 405.38 440.29 1024M-xfs Kswapd efficiency fsmark 79% 71% 1024M-xfs Kswapd efficiency simple-wb 74% 74% 1024M-xfs Kswapd efficiency mmap-strm 39% 42% 1024M-4X-xfs Files/s mean 32.63 ( 0.00%) 35.05 ( 6.90%) 1024M-4X-xfs Elapsed Time fsmark 103.33 97.74 1024M-4X-xfs Elapsed Time simple-wb 204.48 178.57 1024M-4X-xfs Elapsed Time mmap-strm 528.38 511.88 1024M-4X-xfs Kswapd efficiency fsmark 81% 70% 1024M-4X-xfs Kswapd efficiency simple-wb 73% 72% 1024M-4X-xfs Kswapd efficiency mmap-strm 39% 38% 1024M-16X-xfs Files/s mean 42.65 ( 0.00%) 42.97 ( 0.74%) 1024M-16X-xfs Elapsed Time fsmark 103.11 99.11 1024M-16X-xfs Elapsed Time simple-wb 200.83 178.24 1024M-16X-xfs Elapsed Time mmap-strm 397.35 459.82 1024M-16X-xfs Kswapd efficiency fsmark 84% 69% 1024M-16X-xfs Kswapd efficiency simple-wb 74% 73% 1024M-16X-xfs Kswapd efficiency mmap-strm 39% 40% All FSMark tests up to 16X had statistically significant improvements. For the most part, tests are completing faster with the exception of the streaming writes to a mixture of anonymous and file-backed mappings which were slower in two cases In the cases where the mmap-strm tests were slower, there was more swapping due to dirty pages being skipped. The number of additional pages swapped is almost identical to the fewer number of pages written from reclaim. In other words, roughly the same number of pages were reclaimed but swapping was slower. As the test is a bit unrealistic and stresses memory heavily, the small shift is acceptable. 4608M1P-xfs Files/s mean 29.75 ( 0.00%) 30.96 ( 3.91%) 4608M1P-xfs Elapsed Time fsmark 512.01 492.15 4608M1P-xfs Elapsed Time simple-wb 618.18 566.24 4608M1P-xfs Elapsed Time mmap-strm 488.05 465.07 4608M1P-xfs Kswapd efficiency fsmark 93% 86% 4608M1P-xfs Kswapd efficiency simple-wb 88% 84% 4608M1P-xfs Kswapd efficiency mmap-strm 46% 45% 4608M-xfs Files/s mean 27.60 ( 0.00%) 28.85 ( 4.33%) 4608M-xfs Elapsed Time fsmark 555.96 532.34 4608M-xfs Elapsed Time simple-wb 659.72 571.85 4608M-xfs Elapsed Time mmap-strm 1082.57 1146.38 4608M-xfs Kswapd efficiency fsmark 89% 91% 4608M-xfs Kswapd efficiency simple-wb 88% 82% 4608M-xfs Kswapd efficiency mmap-strm 48% 46% 4608M-4X-xfs Files/s mean 26.00 ( 0.00%) 27.47 ( 5.35%) 4608M-4X-xfs Elapsed Time fsmark 592.91 564.00 4608M-4X-xfs Elapsed Time simple-wb 616.65 575.07 4608M-4X-xfs Elapsed Time mmap-strm 1773.02 1631.53 4608M-4X-xfs Kswapd efficiency fsmark 90% 94% 4608M-4X-xfs Kswapd efficiency simple-wb 87% 82% 4608M-4X-xfs Kswapd efficiency mmap-strm 43% 43% 4608M-16X-xfs Files/s mean 26.07 ( 0.00%) 26.42 ( 1.32%) 4608M-16X-xfs Elapsed Time fsmark 602.69 585.78 4608M-16X-xfs Elapsed Time simple-wb 606.60 573.81 4608M-16X-xfs Elapsed Time mmap-strm 1549.75 1441.86 4608M-16X-xfs Kswapd efficiency fsmark 98% 98% 4608M-16X-xfs Kswapd efficiency simple-wb 88% 82% 4608M-16X-xfs Kswapd efficiency mmap-strm 44% 42% Unlike the other tests, the fsmark results are not statistically significant but the min and max times are both improved and for the most part, tests completed faster. There are other indications that this is an improvement as well. For example, in the vast majority of cases, there were fewer pages scanned by direct reclaim implying in many cases that stalls due to direct reclaim are reduced. KSwapd is scanning more due to skipping dirty pages which is unfortunate but the CPU usage is still acceptable In an earlier set of tests, I used blktrace and in almost all cases throughput throughout the entire test was higher. However, I ended up discarding those results as recording blktrace data was too heavy for my liking. On a laptop, I plugged in a USB stick and ran a similar tests of tests using it as backing storage. A desktop environment was running and for the entire duration of the tests, firefox and gnome terminal were launching and exiting to vaguely simulate a user. 1024M-xfs Files/s mean 0.41 ( 0.00%) 0.44 ( 6.82%) 1024M-xfs Elapsed Time fsmark 2053.52 1641.03 1024M-xfs Elapsed Time simple-wb 1229.53 768.05 1024M-xfs Elapsed Time mmap-strm 4126.44 4597.03 1024M-xfs Kswapd efficiency fsmark 84% 85% 1024M-xfs Kswapd efficiency simple-wb 92% 81% 1024M-xfs Kswapd efficiency mmap-strm 60% 51% 1024M-xfs Avg wait ms fsmark 5404.53 4473.87 1024M-xfs Avg wait ms simple-wb 2541.35 1453.54 1024M-xfs Avg wait ms mmap-strm 3400.25 3852.53 The mmap-strm results were hurt because firefox launching had a tendency to push the test out of memory. On the postive side, firefox launched marginally faster with the patches applied. Time to completion for many tests was faster but more importantly - the "Avg wait" time as measured by iostat was far lower implying the system would be more responsive. It was also the case that "Avg wait ms" on the root filesystem was lower. I tested it manually and while the system felt slightly more responsive while copying data to a USB stick, it was marginal enough that it could be my imagination. This patch: do not writeback filesystem pages in direct reclaim. When kswapd is failing to keep zones above the min watermark, a process will enter direct reclaim in the same manner kswapd does. If a dirty page is encountered during the scan, this page is written to backing storage using mapping->writepage. This causes two problems. First, it can result in very deep call stacks, particularly if the target storage or filesystem are complex. Some filesystems ignore write requests from direct reclaim as a result. The second is that a single-page flush is inefficient in terms of IO. While there is an expectation that the elevator will merge requests, this does not always happen. Quoting Christoph Hellwig; The elevator has a relatively small window it can operate on, and can never fix up a bad large scale writeback pattern. This patch prevents direct reclaim writing back filesystem pages by checking if current is kswapd. Anonymous pages are still written to swap as there is not the equivalent of a flusher thread for anonymous pages. If the dirty pages cannot be written back, they are placed back on the LRU lists. There is now a direct dependency on dirty page balancing to prevent too many pages in the system being dirtied which would prevent reclaim making forward progress. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Alex Elder <aelder@sgi.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Chris Mason <chris.mason@oracle.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Johannes Weiner
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f11c0ca501 |
mm: vmscan: drop nr_force_scan[] from get_scan_count
The nr_force_scan[] tuple holds the effective scan numbers for anon and file pages in case the situation called for a forced scan and the regularly calculated scan numbers turned out zero. However, the effective scan number can always be assumed to be SWAP_CLUSTER_MAX right before the division into anon and file. The numerators and denominator are properly set up for all cases, be it force scan for just file, just anon, or both, to do the right thing. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Shaohua Li
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3da367c3e5 |
vmscan: add block plug for page reclaim
per-task block plug can reduce block queue lock contention and increase request merge. Currently page reclaim doesn't support it. I originally thought page reclaim doesn't need it, because kswapd thread count is limited and file cache write is done at flusher mostly. When I test a workload with heavy swap in a 4-node machine, each CPU is doing direct page reclaim and swap. This causes block queue lock contention. In my test, without below patch, the CPU utilization is about 2% ~ 7%. With the patch, the CPU utilization is about 1% ~ 3%. Disk throughput isn't changed. This should improve normal kswapd write and file cache write too (increase request merge for example), but might not be so obvious as I explain above. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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f80c067361 |
mm: zone_reclaim: make isolate_lru_page() filter-aware
In __zone_reclaim case, we don't want to shrink mapped page. Nonetheless, we have isolated mapped page and re-add it into LRU's head. It's unnecessary CPU overhead and makes LRU churning. Of course, when we isolate the page, the page might be mapped but when we try to migrate the page, the page would be not mapped. So it could be migrated. But race is rare and although it happens, it's no big deal. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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39deaf8585 |
mm: compaction: make isolate_lru_page() filter-aware
In async mode, compaction doesn't migrate dirty or writeback pages. So, it's meaningless to pick the page and re-add it to lru list. Of course, when we isolate the page in compaction, the page might be dirty or writeback but when we try to migrate the page, the page would be not dirty, writeback. So it could be migrated. But it's very unlikely as isolate and migration cycle is much faster than writeout. So, this patch helps cpu overhead and prevent unnecessary LRU churning. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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4356f21d09 |
mm: change isolate mode from #define to bitwise type
Change ISOLATE_XXX macro with bitwise isolate_mode_t type. Normally, macro isn't recommended as it's type-unsafe and making debugging harder as symbol cannot be passed throught to the debugger. Quote from Johannes " Hmm, it would probably be cleaner to fully convert the isolation mode into independent flags. INACTIVE, ACTIVE, BOTH is currently a tri-state among flags, which is a bit ugly." This patch moves isolate mode from swap.h to mmzone.h by memcontrol.h Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Curt Wohlgemuth
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0e175a1835 |
writeback: Add a 'reason' to wb_writeback_work
This creates a new 'reason' field in a wb_writeback_work structure, which unambiguously identifies who initiates writeback activity. A 'wb_reason' enumeration has been added to writeback.h, to enumerate the possible reasons. The 'writeback_work_class' and tracepoint event class and 'writeback_queue_io' tracepoints are updated to include the symbolic 'reason' in all trace events. And the 'writeback_inodes_sbXXX' family of routines has had a wb_stats parameter added to them, so callers can specify why writeback is being started. Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Curt Wohlgemuth <curtw@google.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> |
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Jiri Kosina
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e060c38434 |
Merge branch 'master' into for-next
Fast-forward merge with Linus to be able to merge patches based on more recent version of the tree. |
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Johannes Weiner
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185efc0f9a |
memcg: Revert "memcg: add memory.vmscan_stat"
Revert the post-3.0 commit
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Johannes Weiner
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a4d3e9e763 |
mm: vmscan: fix force-scanning small targets without swap
Without swap, anonymous pages are not scanned. As such, they should not
count when considering force-scanning a small target if there is no swap.
Otherwise, targets are not force-scanned even when their effective scan
number is zero and the other conditions--kswapd/memcg--apply.
This fixes
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Shaohua Li
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439423f689 |
vmscan: clear ZONE_CONGESTED for zone with good watermark
ZONE_CONGESTED is only cleared in kswapd, but pages can be freed in any
task. It's possible ZONE_CONGESTED isn't cleared in some cases:
1. the zone is already balanced just entering balance_pgdat() for
order-0 because concurrent tasks free memory. In this case, later
check will skip the zone as it's balanced so the flag isn't cleared.
2. high order balance fallbacks to order-0. quote from Mel: At the
end of balance_pgdat(), kswapd uses the following logic;
If reclaiming at high order {
for each zone {
if all_unreclaimable
skip
if watermark is not met
order = 0
loop again
/* watermark is met */
clear congested
}
}
i.e. it clears ZONE_CONGESTED if it the zone is balanced. if not,
it restarts balancing at order-0. However, if the higher zones are
balanced for order-0, kswapd will miss clearing ZONE_CONGESTED as
that only happens after a zone is shrunk. This can mean that
wait_iff_congested() stalls unnecessarily.
This patch makes kswapd clear ZONE_CONGESTED during its initial
highmem->dma scan for zones that are already balanced.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Shaohua Li
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f51bdd2e97 |
mm: fix a vmscan warning
I get the below warning: BUG: using smp_processor_id() in preemptible [00000000] code: bash/746 caller is native_sched_clock+0x37/0x6e Pid: 746, comm: bash Tainted: G W 3.0.0+ #254 Call Trace: [<ffffffff813435c6>] debug_smp_processor_id+0xc2/0xdc [<ffffffff8104158d>] native_sched_clock+0x37/0x6e [<ffffffff81116219>] try_to_free_mem_cgroup_pages+0x7d/0x270 [<ffffffff8114f1f8>] mem_cgroup_force_empty+0x24b/0x27a [<ffffffff8114ff21>] ? sys_close+0x38/0x138 [<ffffffff8114ff21>] ? sys_close+0x38/0x138 [<ffffffff8114f257>] mem_cgroup_force_empty_write+0x17/0x19 [<ffffffff810c72fb>] cgroup_file_write+0xa8/0xba [<ffffffff811522d2>] vfs_write+0xb3/0x138 [<ffffffff8115241a>] sys_write+0x4a/0x71 [<ffffffff8114ffd9>] ? sys_close+0xf0/0x138 [<ffffffff8176deab>] system_call_fastpath+0x16/0x1b sched_clock() can't be used with preempt enabled. And we don't need fast approach to get clock here, so let's use ktime API. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Justin P. Mattock
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81d66c70b5 |
mm/vmscan.c: fix a typo in a comment "relaimed" to "reclaimed"
Signed-off-by: Justin P. Mattock <justinmattock@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz> |
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KAMEZAWA Hiroyuki
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82f9d486e5 |
memcg: add memory.vmscan_stat
The commit log of
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KAMEZAWA Hiroyuki
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4508378b95 |
memcg: fix vmscan count in small memcgs
Commit
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KAMEZAWA Hiroyuki
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bb2a0de92c |
memcg: consolidate memory cgroup lru stat functions
In mm/memcontrol.c, there are many lru stat functions as..
mem_cgroup_zone_nr_lru_pages
mem_cgroup_node_nr_file_lru_pages
mem_cgroup_nr_file_lru_pages
mem_cgroup_node_nr_anon_lru_pages
mem_cgroup_nr_anon_lru_pages
mem_cgroup_node_nr_unevictable_lru_pages
mem_cgroup_nr_unevictable_lru_pages
mem_cgroup_node_nr_lru_pages
mem_cgroup_nr_lru_pages
mem_cgroup_get_local_zonestat
Some of them are under #ifdef MAX_NUMNODES >1 and others are not.
This seems bad. This patch consolidates all functions into
mem_cgroup_zone_nr_lru_pages()
mem_cgroup_node_nr_lru_pages()
mem_cgroup_nr_lru_pages()
For these functions, "which LRU?" information is passed by a mask.
example:
mem_cgroup_nr_lru_pages(mem, BIT(LRU_ACTIVE_ANON))
And I added some macro as ALL_LRU, ALL_LRU_FILE, ALL_LRU_ANON.
example:
mem_cgroup_nr_lru_pages(mem, ALL_LRU)
BTW, considering layout of NUMA memory placement of counters, this patch seems
to be better.
Now, when we gather all LRU information, we scan in following orer
for_each_lru -> for_each_node -> for_each_zone.
This means we'll touch cache lines in different node in turn.
After patch, we'll scan
for_each_node -> for_each_zone -> for_each_lru(mask)
Then, we'll gather information in the same cacheline at once.
[akpm@linux-foundation.org: fix warnigns, build error]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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KAMEZAWA Hiroyuki
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1f4c025b5a |
memcg: export memory cgroup's swappiness with mem_cgroup_swappiness()
Each memory cgroup has a 'swappiness' value which can be accessed by get_swappiness(memcg). The major user is try_to_free_mem_cgroup_pages() and swappiness is passed by argument. It's propagated by scan_control. get_swappiness() is a static function but some planned updates will need to get swappiness from files other than memcontrol.c This patch exports get_swappiness() as mem_cgroup_swappiness(). With this, we can remove the argument of swapiness from try_to_free... and drop swappiness from scan_control. only memcg uses it. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Michal Hocko <mhocko@suse.cz> Cc: Ying Han <yinghan@google.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Dave Chinner
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e9299f5058 |
vmscan: add customisable shrinker batch size
For shrinkers that have their own cond_resched* calls, having shrink_slab break the work down into small batches is not paticularly efficient. Add a custom batchsize field to the struct shrinker so that shrinkers can use a larger batch size if they desire. A value of zero (uninitialised) means "use the default", so behaviour is unchanged by this patch. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Dave Chinner
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3567b59aa8 |
vmscan: reduce wind up shrinker->nr when shrinker can't do work
When a shrinker returns -1 to shrink_slab() to indicate it cannot do any work given the current memory reclaim requirements, it adds the entire total_scan count to shrinker->nr. The idea ehind this is that whenteh shrinker is next called and can do work, it will do the work of the previously aborted shrinker call as well. However, if a filesystem is doing lots of allocation with GFP_NOFS set, then we get many, many more aborts from the shrinkers than we do successful calls. The result is that shrinker->nr winds up to it's maximum permissible value (twice the current cache size) and then when the next shrinker call that can do work is issued, it has enough scan count built up to free the entire cache twice over. This manifests itself in the cache going from full to empty in a matter of seconds, even when only a small part of the cache is needed to be emptied to free sufficient memory. Under metadata intensive workloads on ext4 and XFS, I'm seeing the VFS caches increase memory consumption up to 75% of memory (no page cache pressure) over a period of 30-60s, and then the shrinker empties them down to zero in the space of 2-3s. This cycle repeats over and over again, with the shrinker completely trashing the inode and dentry caches every minute or so the workload continues. This behaviour was made obvious by the shrink_slab tracepoints added earlier in the series, and made worse by the patch that corrected the concurrent accounting of shrinker->nr. To avoid this problem, stop repeated small increments of the total scan value from winding shrinker->nr up to a value that can cause the entire cache to be freed. We still need to allow it to wind up, so use the delta as the "large scan" threshold check - if the delta is more than a quarter of the entire cache size, then it is a large scan and allowed to cause lots of windup because we are clearly needing to free lots of memory. If it isn't a large scan then limit the total scan to half the size of the cache so that windup never increases to consume the whole cache. Reducing the total scan limit further does not allow enough wind-up to maintain the current levels of performance, whilst a higher threshold does not prevent the windup from freeing the entire cache under sustained workloads. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Dave Chinner
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acf92b485c |
vmscan: shrinker->nr updates race and go wrong
shrink_slab() allows shrinkers to be called in parallel so the struct shrinker can be updated concurrently. It does not provide any exclusio for such updates, so we can get the shrinker->nr value increasing or decreasing incorrectly. As a result, when a shrinker repeatedly returns a value of -1 (e.g. a VFS shrinker called w/ GFP_NOFS), the shrinker->nr goes haywire, sometimes updating with the scan count that wasn't used, sometimes losing it altogether. Worse is when a shrinker does work and that update is lost due to racy updates, which means the shrinker will do the work again! Fix this by making the total_scan calculations independent of shrinker->nr, and making the shrinker->nr updates atomic w.r.t. to other updates via cmpxchg loops. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Dave Chinner
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095760730c |
vmscan: add shrink_slab tracepoints
It is impossible to understand what the shrinkers are actually doing without instrumenting the code, so add a some tracepoints to allow insight to be gained. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Shaohua Li
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4746efded8 |
vmscan: fix a livelock in kswapd
I'm running a workload which triggers a lot of swap in a machine with 4
nodes. After I kill the workload, I found a kswapd livelock. Sometimes
kswapd3 or kswapd2 are keeping running and I can't access filesystem,
but most memory is free.
This looks like a regression since commit
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Mel Gorman
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215ddd6664 |
mm: vmscan: only read new_classzone_idx from pgdat when reclaiming successfully
During allocator-intensive workloads, kswapd will be woken frequently causing free memory to oscillate between the high and min watermark. This is expected behaviour. Unfortunately, if the highest zone is small, a problem occurs. When balance_pgdat() returns, it may be at a lower classzone_idx than it started because the highest zone was unreclaimable. Before checking if it should go to sleep though, it checks pgdat->classzone_idx which when there is no other activity will be MAX_NR_ZONES-1. It interprets this as it has been woken up while reclaiming, skips scheduling and reclaims again. As there is no useful reclaim work to do, it enters into a loop of shrinking slab consuming loads of CPU until the highest zone becomes reclaimable for a long period of time. There are two problems here. 1) If the returned classzone or order is lower, it'll continue reclaiming without scheduling. 2) if the highest zone was marked unreclaimable but balance_pgdat() returns immediately at DEF_PRIORITY, the new lower classzone is not communicated back to kswapd() for sleeping. This patch does two things that are related. If the end_zone is unreclaimable, this information is communicated back. Second, if the classzone or order was reduced due to failing to reclaim, new information is not read from pgdat and instead an attempt is made to go to sleep. Due to this, it is also necessary that pgdat->classzone_idx be initialised each time to pgdat->nr_zones - 1 to avoid re-reads being interpreted as wakeups. Signed-off-by: Mel Gorman <mgorman@suse.de> Reported-by: Pádraig Brady <P@draigBrady.com> Tested-by: Pádraig Brady <P@draigBrady.com> Tested-by: Andrew Lutomirski <luto@mit.edu> Acked-by: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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da175d06b4 |
mm: vmscan: evaluate the watermarks against the correct classzone
When deciding if kswapd is sleeping prematurely, the classzone is taken into account but this is different to what balance_pgdat() and the allocator are doing. Specifically, the DMA zone will be checked based on the classzone used when waking kswapd which could be for a GFP_KERNEL or GFP_HIGHMEM request. The lowmem reserve limit kicks in, the watermark is not met and kswapd thinks it's sleeping prematurely keeping kswapd awake in error. Signed-off-by: Mel Gorman <mgorman@suse.de> Reported-by: Pádraig Brady <P@draigBrady.com> Tested-by: Pádraig Brady <P@draigBrady.com> Tested-by: Andrew Lutomirski <luto@mit.edu> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
|
d7868dae89 |
mm: vmscan: do not apply pressure to slab if we are not applying pressure to zone
During allocator-intensive workloads, kswapd will be woken frequently causing free memory to oscillate between the high and min watermark. This is expected behaviour. When kswapd applies pressure to zones during node balancing, it checks if the zone is above a high+balance_gap threshold. If it is, it does not apply pressure but it unconditionally shrinks slab on a global basis which is excessive. In the event kswapd is being kept awake due to a high small unreclaimable zone, it skips zone shrinking but still calls shrink_slab(). Once pressure has been applied, the check for zone being unreclaimable is being made before the check is made if all_unreclaimable should be set. This miss of unreclaimable can cause has_under_min_watermark_zone to be set due to an unreclaimable zone preventing kswapd backing off on congestion_wait(). Signed-off-by: Mel Gorman <mgorman@suse.de> Reported-by: Pádraig Brady <P@draigBrady.com> Tested-by: Pádraig Brady <P@draigBrady.com> Tested-by: Andrew Lutomirski <luto@mit.edu> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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08951e5459 |
mm: vmscan: correct check for kswapd sleeping in sleeping_prematurely
During allocator-intensive workloads, kswapd will be woken frequently
causing free memory to oscillate between the high and min watermark. This
is expected behaviour. Unfortunately, if the highest zone is small, a
problem occurs.
This seems to happen most with recent sandybridge laptops but it's
probably a co-incidence as some of these laptops just happen to have a
small Normal zone. The reproduction case is almost always during copying
large files that kswapd pegs at 100% CPU until the file is deleted or
cache is dropped.
The problem is mostly down to sleeping_prematurely() keeping kswapd awake
when the highest zone is small and unreclaimable and compounded by the
fact we shrink slabs even when not shrinking zones causing a lot of time
to be spent in shrinkers and a lot of memory to be reclaimed.
Patch 1 corrects sleeping_prematurely to check the zones matching
the classzone_idx instead of all zones.
Patch 2 avoids shrinking slab when we are not shrinking a zone.
Patch 3 notes that sleeping_prematurely is checking lower zones against
a high classzone which is not what allocators or balance_pgdat()
is doing leading to an artifical belief that kswapd should be
still awake.
Patch 4 notes that when balance_pgdat() gives up on a high zone that the
decision is not communicated to sleeping_prematurely()
This problem affects 2.6.38.8 for certain and is expected to affect 2.6.39
and 3.0-rc4 as well. If accepted, they need to go to -stable to be picked
up by distros and this series is against 3.0-rc4. I've cc'd people that
reported similar problems recently to see if they still suffer from the
problem and if this fixes it.
This patch: correct the check for kswapd sleeping in sleeping_prematurely()
During allocator-intensive workloads, kswapd will be woken frequently
causing free memory to oscillate between the high and min watermark. This
is expected behaviour.
A problem occurs if the highest zone is small. balance_pgdat() only
considers unreclaimable zones when priority is DEF_PRIORITY but
sleeping_prematurely considers all zones. It's possible for this sequence
to occur
1. kswapd wakes up and enters balance_pgdat()
2. At DEF_PRIORITY, marks highest zone unreclaimable
3. At DEF_PRIORITY-1, ignores highest zone setting end_zone
4. At DEF_PRIORITY-1, calls shrink_slab freeing memory from
highest zone, clearing all_unreclaimable. Highest zone
is still unbalanced
5. kswapd returns and calls sleeping_prematurely
6. sleeping_prematurely looks at *all* zones, not just the ones
being considered by balance_pgdat. The highest small zone
has all_unreclaimable cleared but the zone is not
balanced. all_zones_ok is false so kswapd stays awake
This patch corrects the behaviour of sleeping_prematurely to check the
zones balance_pgdat() checked.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reported-by: Pádraig Brady <P@draigBrady.com>
Tested-by: Pádraig Brady <P@draigBrady.com>
Tested-by: Andrew Lutomirski <luto@mit.edu>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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KAMEZAWA Hiroyuki
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ac34a1a3c3 |
memcg: fix direct softlimit reclaim to be called in limit path
Commit
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Andrea Arcangeli
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d179e84ba5 |
mm: vmscan: do not use page_count without a page pin
It is unsafe to run page_count during the physical pfn scan because compound_head could trip on a dangling pointer when reading page->first_page if the compound page is being freed by another CPU. [mgorman@suse.de: split out patch] Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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KOSAKI Motohiro
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a433658c30 |
vmscan,memcg: memcg aware swap token
Currently, memcg reclaim can disable swap token even if the swap token mm doesn't belong in its memory cgroup. It's slightly risky. If an admin creates very small mem-cgroup and silly guy runs contentious heavy memory pressure workload, every tasks are going to lose swap token and then system may become unresponsive. That's bad. This patch adds 'memcg' parameter into disable_swap_token(). and if the parameter doesn't match swap token, VM doesn't disable it. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Rik van Riel<riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ying Han
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1bac180bd2 |
memcg: rename mem_cgroup_zone_nr_pages() to mem_cgroup_zone_nr_lru_pages()
The caller of the function has been renamed to zone_nr_lru_pages(), and this is just fixing up in the memcg code. The current name is easily to be mis-read as zone's total number of pages. Signed-off-by: Ying Han <yinghan@google.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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KAMEZAWA Hiroyuki
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246e87a939 |
memcg: fix get_scan_count() for small targets
During memory reclaim we determine the number of pages to be scanned per
zone as
(anon + file) >> priority.
Assume
scan = (anon + file) >> priority.
If scan < SWAP_CLUSTER_MAX, the scan will be skipped for this time and
priority gets higher. This has some problems.
1. This increases priority as 1 without any scan.
To do scan in this priority, amount of pages should be larger than 512M.
If pages>>priority < SWAP_CLUSTER_MAX, it's recorded and scan will be
batched, later. (But we lose 1 priority.)
If memory size is below 16M, pages >> priority is 0 and no scan in
DEF_PRIORITY forever.
2. If zone->all_unreclaimabe==true, it's scanned only when priority==0.
So, x86's ZONE_DMA will never be recoverred until the user of pages
frees memory by itself.
3. With memcg, the limit of memory can be small. When using small memcg,
it gets priority < DEF_PRIORITY-2 very easily and need to call
wait_iff_congested().
For doing scan before priorty=9, 64MB of memory should be used.
Then, this patch tries to scan SWAP_CLUSTER_MAX of pages in force...when
1. the target is enough small.
2. it's kswapd or memcg reclaim.
Then we can avoid rapid priority drop and may be able to recover
all_unreclaimable in a small zones. And this patch removes nr_saved_scan.
This will allow scanning in this priority even when pages >> priority is
very small.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Ying Han <yinghan@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Ying Han
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889976dbcb |
memcg: reclaim memory from nodes in round-robin order
Presently, memory cgroup's direct reclaim frees memory from the current node. But this has some troubles. Usually when a set of threads works in a cooperative way, they tend to operate on the same node. So if they hit limits under memcg they will reclaim memory from themselves, damaging the active working set. For example, assume 2 node system which has Node 0 and Node 1 and a memcg which has 1G limit. After some work, file cache remains and the usages are Node 0: 1M Node 1: 998M. and run an application on Node 0, it will eat its foot before freeing unnecessary file caches. This patch adds round-robin for NUMA and adds equal pressure to each node. When using cpuset's spread memory feature, this will work very well. But yes, a better algorithm is needed. [akpm@linux-foundation.org: comment editing] [kamezawa.hiroyu@jp.fujitsu.com: fix time comparisons] Signed-off-by: Ying Han <yinghan@google.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ying Han
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d149e3b25d |
memcg: add the soft_limit reclaim in global direct reclaim.
We recently added the change in global background reclaim which counts the return value of soft_limit reclaim. Now this patch adds the similar logic on global direct reclaim. We should skip scanning global LRU on shrink_zone if soft_limit reclaim does enough work. This is the first step where we start with counting the nr_scanned and nr_reclaimed from soft_limit reclaim into global scan_control. Signed-off-by: Ying Han <yinghan@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ying Han
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0ae5e89c60 |
memcg: count the soft_limit reclaim in global background reclaim
The global kswapd scans per-zone LRU and reclaims pages regardless of the cgroup. It breaks memory isolation since one cgroup can end up reclaiming pages from another cgroup. Instead we should rely on memcg-aware target reclaim including per-memcg kswapd and soft_limit hierarchical reclaim under memory pressure. In the global background reclaim, we do soft reclaim before scanning the per-zone LRU. However, the return value is ignored. This patch is the first step to skip shrink_zone() if soft_limit reclaim does enough work. This is part of the effort which tries to reduce reclaiming pages in global LRU in memcg. The per-memcg background reclaim patchset further enhances the per-cgroup targetting reclaim, which I should have V4 posted shortly. Try running multiple memory intensive workloads within seperate memcgs. Watch the counters of soft_steal in memory.stat. $ cat /dev/cgroup/A/memory.stat | grep 'soft' soft_steal 240000 soft_scan 240000 total_soft_steal 240000 total_soft_scan 240000 This patch: In the global background reclaim, we do soft reclaim before scanning the per-zone LRU. However, the return value is ignored. We would like to skip shrink_zone() if soft_limit reclaim does enough work. Also, we need to make the memory pressure balanced across per-memcg zones, like the logic vm-core. This patch is the first step where we start with counting the nr_scanned and nr_reclaimed from soft_limit reclaim into the global scan_control. Signed-off-by: Ying Han <yinghan@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@in.ibm.com> Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ying Han
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1495f230fa |
vmscan: change shrinker API by passing shrink_control struct
Change each shrinker's API by consolidating the existing parameters into shrink_control struct. This will simplify any further features added w/o touching each file of shrinker. [akpm@linux-foundation.org: fix build] [akpm@linux-foundation.org: fix warning] [kosaki.motohiro@jp.fujitsu.com: fix up new shrinker API] [akpm@linux-foundation.org: fix xfs warning] [akpm@linux-foundation.org: update gfs2] Signed-off-by: Ying Han <yinghan@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Acked-by: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Acked-by: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ying Han
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a09ed5e000 |
vmscan: change shrink_slab() interfaces by passing shrink_control
Consolidate the existing parameters to shrink_slab() into a new shrink_control struct. This is needed later to pass the same struct to shrinkers. Signed-off-by: Ying Han <yinghan@google.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Acked-by: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Acked-by: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Konstantin Khlebnikov
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0c917313a8 |
mm: strictly require elevated page refcount in isolate_lru_page()
isolate_lru_page() must be called only with stable reference to the page, this is what is written in the comment above it, this is reasonable. current isolate_lru_page() users and its page extra reference sources: mm/huge_memory.c: __collapse_huge_page_isolate() - reference from pte mm/memcontrol.c: mem_cgroup_move_parent() - get_page_unless_zero() mem_cgroup_move_charge_pte_range() - reference from pte mm/memory-failure.c: soft_offline_page() - fixed, reference from get_any_page() delete_from_lru_cache() - reference from caller or get_page_unless_zero() [ seems like there bug, because __memory_failure() can call page_action() for hpages tail, but it is ok for isolate_lru_page(), tail getted and not in lru] mm/memory_hotplug.c: do_migrate_range() - fixed, get_page_unless_zero() mm/mempolicy.c: migrate_page_add() - reference from pte mm/migrate.c: do_move_page_to_node_array() - reference from follow_page() mlock.c: - various external references mm/vmscan.c: putback_lru_page() - reference from isolate_lru_page() It seems that all isolate_lru_page() users are ready now for this restriction. So, let's replace redundant get_page_unless_zero() with get_page() and add page initial reference count check with VM_BUG_ON() Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Andi Kleen <andi@firstfloor.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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f06590bd71 |
mm: vmscan: correctly check if reclaimer should schedule during shrink_slab
It has been reported on some laptops that kswapd is consuming large
amounts of CPU and not being scheduled when SLUB is enabled during large
amounts of file copying. It is expected that this is due to kswapd
missing every cond_resched() point because;
shrink_page_list() calls cond_resched() if inactive pages were isolated
which in turn may not happen if all_unreclaimable is set in
shrink_zones(). If for whatver reason, all_unreclaimable is
set on all zones, we can miss calling cond_resched().
balance_pgdat() only calls cond_resched if the zones are not
balanced. For a high-order allocation that is balanced, it
checks order-0 again. During that window, order-0 might have
become unbalanced so it loops again for order-0 and returns
that it was reclaiming for order-0 to kswapd(). It can then
find that a caller has rewoken kswapd for a high-order and
re-enters balance_pgdat() without ever calling cond_resched().
shrink_slab only calls cond_resched() if we are reclaiming slab
pages. If there are a large number of direct reclaimers, the
shrinker_rwsem can be contended and prevent kswapd calling
cond_resched().
This patch modifies the shrink_slab() case. If the semaphore is
contended, the caller will still check cond_resched(). After each
successful call into a shrinker, the check for cond_resched() remains in
case one shrinker is particularly slow.
[mgorman@suse.de: preserve call to cond_resched after each call into shrinker]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Tested-by: Colin King <colin.king@canonical.com>
Cc: Raghavendra D Prabhu <raghu.prabhu13@gmail.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: <stable@kernel.org> [2.6.38+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Johannes Weiner
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afc7e326a3 |
mm: vmscan: correct use of pgdat_balanced in sleeping_prematurely
There are a few reports of people experiencing hangs when copying large amounts of data with kswapd using a large amount of CPU which appear to be due to recent reclaim changes. SLUB using high orders is the trigger but not the root cause as SLUB has been using high orders for a while. The root cause was bugs introduced into reclaim which are addressed by the following two patches. Patch 1 corrects logic introduced by commit |
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Linus Torvalds
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268bb0ce3e |
sanitize <linux/prefetch.h> usage
Commit
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KAMEZAWA Hiroyuki
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d6c438b6cd |
memcg: fix zone congestion
ZONE_CONGESTED should be a state of global memory reclaim. If not, a busy memcg sets this and give unnecessary throttoling in wait_iff_congested() against memory recalim in other contexts. This makes system performance bad. I'll think about "memcg is congested!" flag is required or not, later. But this fix is required first. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Ying Han <yinghan@google.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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KOSAKI Motohiro
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929bea7c71 |
vmscan: all_unreclaimable() use zone->all_unreclaimable as a name
all_unreclaimable check in direct reclaim has been introduced at 2.6.19
by following commit.
2006 Sep 25; commit 408d8544; oom: use unreclaimable info
And it went through strange history. firstly, following commit broke
the logic unintentionally.
2008 Apr 29; commit a41f24ea; page allocator: smarter retry of
costly-order allocations
Two years later, I've found obvious meaningless code fragment and
restored original intention by following commit.
2010 Jun 04; commit bb21c7ce; vmscan: fix do_try_to_free_pages()
return value when priority==0
But, the logic didn't works when 32bit highmem system goes hibernation
and Minchan slightly changed the algorithm and fixed it .
2010 Sep 22: commit d1908362: vmscan: check all_unreclaimable
in direct reclaim path
But, recently, Andrey Vagin found the new corner case. Look,
struct zone {
..
int all_unreclaimable;
..
unsigned long pages_scanned;
..
}
zone->all_unreclaimable and zone->pages_scanned are neigher atomic
variables nor protected by lock. Therefore zones can become a state of
zone->page_scanned=0 and zone->all_unreclaimable=1. In this case, current
all_unreclaimable() return false even though zone->all_unreclaimabe=1.
This resulted in the kernel hanging up when executing a loop of the form
1. fork
2. mmap
3. touch memory
4. read memory
5. munmmap
as described in
http://www.gossamer-threads.com/lists/linux/kernel/1348725#1348725
Is this ignorable minor issue? No. Unfortunately, x86 has very small dma
zone and it become zone->all_unreclamble=1 easily. and if it become
all_unreclaimable=1, it never restore all_unreclaimable=0. Why? if
all_unreclaimable=1, vmscan only try DEF_PRIORITY reclaim and
a-few-lru-pages>>DEF_PRIORITY always makes 0. that mean no page scan at
all!
Eventually, oom-killer never works on such systems. That said, we can't
use zone->pages_scanned for this purpose. This patch restore
all_unreclaimable() use zone->all_unreclaimable as old. and in addition,
to add oom_killer_disabled check to avoid reintroduce the issue of commit
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Lucas De Marchi
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25985edced |
Fix common misspellings
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi> |
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Linus Torvalds
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6c51038900 |
Merge branch 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits)
Documentation/iostats.txt: bit-size reference etc.
cfq-iosched: removing unnecessary think time checking
cfq-iosched: Don't clear queue stats when preempt.
blk-throttle: Reset group slice when limits are changed
blk-cgroup: Only give unaccounted_time under debug
cfq-iosched: Don't set active queue in preempt
block: fix non-atomic access to genhd inflight structures
block: attempt to merge with existing requests on plug flush
block: NULL dereference on error path in __blkdev_get()
cfq-iosched: Don't update group weights when on service tree
fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away
block: Require subsystems to explicitly allocate bio_set integrity mempool
jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging
fs: make fsync_buffers_list() plug
mm: make generic_writepages() use plugging
blk-cgroup: Add unaccounted time to timeslice_used.
block: fixup plugging stubs for !CONFIG_BLOCK
block: remove obsolete comments for blkdev_issue_zeroout.
blktrace: Use rq->cmd_flags directly in blk_add_trace_rq.
...
Fix up conflicts in fs/{aio.c,super.c}
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Mel Gorman
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8afdcece49 |
mm: vmscan: kswapd should not free an excessive number of pages when balancing small zones
When reclaiming for order-0 pages, kswapd requires that all zones be balanced. Each cycle through balance_pgdat() does background ageing on all zones if necessary and applies equal pressure on the inactive zone unless a lot of pages are free already. A "lot of free pages" is defined as a "balance gap" above the high watermark which is currently 7*high_watermark. Historically this was reasonable as min_free_kbytes was small. However, on systems using huge pages, it is recommended that min_free_kbytes is higher and it is tuned with hugeadm --set-recommended-min_free_kbytes. With the introduction of transparent huge page support, this recommended value is also applied. On X86-64 with 4G of memory, min_free_kbytes becomes 67584 so one would expect around 68M of memory to be free. The Normal zone is approximately 35000 pages so under even normal memory pressure such as copying a large file, it gets exhausted quickly. As it is getting exhausted, kswapd applies pressure equally to all zones, including the DMA32 zone. DMA32 is approximately 700,000 pages with a high watermark of around 23,000 pages. In this situation, kswapd will reclaim around (23000*8 where 8 is the high watermark + balance gap of 7 * high watermark) pages or 718M of pages before the zone is ignored. What the user sees is that free memory far higher than it should be. To avoid an excessive number of pages being reclaimed from the larger zones, explicitely defines the "balance gap" to be either 1% of the zone or the low watermark for the zone, whichever is smaller. While kswapd will check all zones to apply pressure, it'll ignore zones that meets the (high_wmark + balance_gap) watermark. To test this, 80G were copied from a partition and the amount of memory being used was recorded. A comparison of a patch and unpatched kernel can be seen at http://www.csn.ul.ie/~mel/postings/minfree-20110222/memory-usage-hydra.ps and shows that kswapd is not reclaiming as much memory with the patch applied. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Rik van Riel <riel@redhat.com> Cc: Shaohua Li <shaohua.li@intel.com> Cc: "Chen, Tim C" <tim.c.chen@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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e64a782fec |
mm: change __remove_from_page_cache()
Now we renamed remove_from_page_cache with delete_from_page_cache. As consistency of __remove_from_swap_cache and remove_from_swap_cache, we change internal page cache handling function name, too. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andrea Arcangeli
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d527caf22e |
mm: compaction: prevent kswapd compacting memory to reduce CPU usage
This patch reverts |
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Jens Axboe
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4c63f5646e |
Merge branch 'for-2.6.39/stack-plug' into for-2.6.39/core
Conflicts: block/blk-core.c block/blk-flush.c drivers/md/raid1.c drivers/md/raid10.c drivers/md/raid5.c fs/nilfs2/btnode.c fs/nilfs2/mdt.c Signed-off-by: Jens Axboe <jaxboe@fusionio.com> |
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Jens Axboe
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7eaceaccab |
block: remove per-queue plugging
Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe <jaxboe@fusionio.com> |
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Mel Gorman
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2876592f23 |
mm: vmscan: stop reclaim/compaction earlier due to insufficient progress if !__GFP_REPEAT
should_continue_reclaim() for reclaim/compaction allows scanning to
continue even if pages are not being reclaimed until the full list is
scanned. In terms of allocation success, this makes sense but potentially
it introduces unwanted latency for high-order allocations such as
transparent hugepages and network jumbo frames that would prefer to fail
the allocation attempt and fallback to order-0 pages. Worse, there is a
potential that the full LRU scan will clear all the young bits, distort
page aging information and potentially push pages into swap that would
have otherwise remained resident.
This patch will stop reclaim/compaction if no pages were reclaimed in the
last SWAP_CLUSTER_MAX pages that were considered. For allocations such as
hugetlbfs that use __GFP_REPEAT and have fewer fallback options, the full
LRU list may still be scanned.
Order-0 allocation should not be affected because RECLAIM_MODE_COMPACTION
is not set so the following avoids the gfp_mask being examined:
if (!(sc->reclaim_mode & RECLAIM_MODE_COMPACTION))
return false;
A tool was developed based on ftrace that tracked the latency of
high-order allocations while transparent hugepage support was enabled and
three benchmarks were run. The "fix-infinite" figures are 2.6.38-rc4 with
Johannes's patch "vmscan: fix zone shrinking exit when scan work is done"
applied.
STREAM Highorder Allocation Latency Statistics
fix-infinite break-early
1 :: Count 10298 10229
1 :: Min 0.4560 0.4640
1 :: Mean 1.0589 1.0183
1 :: Max 14.5990 11.7510
1 :: Stddev 0.5208 0.4719
2 :: Count 2 1
2 :: Min 1.8610 3.7240
2 :: Mean 3.4325 3.7240
2 :: Max 5.0040 3.7240
2 :: Stddev 1.5715 0.0000
9 :: Count 111696 111694
9 :: Min 0.5230 0.4110
9 :: Mean 10.5831 10.5718
9 :: Max 38.4480 43.2900
9 :: Stddev 1.1147 1.1325
Mean time for order-1 allocations is reduced. order-2 looks increased but
with so few allocations, it's not particularly significant. THP mean
allocation latency is also reduced. That said, allocation time varies so
significantly that the reductions are within noise.
Max allocation time is reduced by a significant amount for low-order
allocations but reduced for THP allocations which presumably are now
breaking before reclaim has done enough work.
SysBench Highorder Allocation Latency Statistics
fix-infinite break-early
1 :: Count 15745 15677
1 :: Min 0.4250 0.4550
1 :: Mean 1.1023 1.0810
1 :: Max 14.4590 10.8220
1 :: Stddev 0.5117 0.5100
2 :: Count 1 1
2 :: Min 3.0040 2.1530
2 :: Mean 3.0040 2.1530
2 :: Max 3.0040 2.1530
2 :: Stddev 0.0000 0.0000
9 :: Count 2017 1931
9 :: Min 0.4980 0.7480
9 :: Mean 10.4717 10.3840
9 :: Max 24.9460 26.2500
9 :: Stddev 1.1726 1.1966
Again, mean time for order-1 allocations is reduced while order-2
allocations are too few to draw conclusions from. The mean time for THP
allocations is also slightly reduced albeit the reductions are within
varianes.
Once again, our maximum allocation time is significantly reduced for
low-order allocations and slightly increased for THP allocations.
Anon stream mmap reference Highorder Allocation Latency Statistics
1 :: Count 1376 1790
1 :: Min 0.4940 0.5010
1 :: Mean 1.0289 0.9732
1 :: Max 6.2670 4.2540
1 :: Stddev 0.4142 0.2785
2 :: Count 1 -
2 :: Min 1.9060 -
2 :: Mean 1.9060 -
2 :: Max 1.9060 -
2 :: Stddev 0.0000 -
9 :: Count 11266 11257
9 :: Min 0.4990 0.4940
9 :: Mean 27250.4669 24256.1919
9 :: Max 11439211.0000 6008885.0000
9 :: Stddev 226427.4624 186298.1430
This benchmark creates one thread per CPU which references an amount of
anonymous memory 1.5 times the size of physical RAM. This pounds swap
quite heavily and is intended to exercise THP a bit.
Mean allocation time for order-1 is reduced as before. It's also reduced
for THP allocations but the variations here are pretty massive due to
swap. As before, maximum allocation times are significantly reduced.
Overall, the patch reduces the mean and maximum allocation latencies for
the smaller high-order allocations. This was with Slab configured so it
would be expected to be more significant with Slub which uses these size
allocations more aggressively.
The mean allocation times for THP allocations are also slightly reduced.
The maximum latency was slightly increased as predicted by the comments
due to reclaim/compaction breaking early. However, workloads care more
about the latency of lower-order allocations than THP so it's an
acceptable trade-off.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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