The rcu callback rcu_free_va() just calls a kfree(),
so we use kfree_rcu() instead of the call_rcu(rcu_free_va).
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: David Rientjes <rientjes@google.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Reduce high order allocations for some setups.
(NR_CPUS=4096 -> we need 64KB per kmem_cache struct)
We now allocate exact needed size (using nr_cpu_ids and nr_node_ids)
This also makes code a bit smaller on x86_64, since some field offsets
are less than the 127 limit :
Before patch :
# size mm/slab.o
text data bss dec hex filename
22605 361665 32 384302 5dd2e mm/slab.o
After patch :
# size mm/slab.o
text data bss dec hex filename
22349 353473 8224 384046 5dc2e mm/slab.o
CC: Andrew Morton <akpm@linux-foundation.org>
Reported-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
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>
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>
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>
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>
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 08951e5459 ("mm: vmscan:
correct check for kswapd sleeping in sleeping_prematurely").
Node 2 and 3 have only ZONE_NORMAL, but balance_pgdat() will return 0
for classzone_idx. The reason is end_zone in balance_pgdat() is 0 by
default, if all zones have watermark ok, end_zone will keep 0.
Later sleeping_prematurely() always returns true. Because this is an
order 3 wakeup, and if classzone_idx is 0, both balanced_pages and
present_pages in pgdat_balanced() are 0. We add a special case here.
If a zone has no page, we think it's balanced. This fixes the livelock.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix CONFIG_SLAB=y CONFIG_DEBUG_SLAB=y build error and warnings.
Now that ARCH_SLAB_MINALIGN defaults to __alignof__(unsigned long long),
it is always defined (when slab.h included), but cannot be used in #if:
mm/slab.c: In function `cache_alloc_debugcheck_after':
mm/slab.c:3156:5: warning: "__alignof__" is not defined
mm/slab.c:3156:5: error: missing binary operator before token "("
make[1]: *** [mm/slab.o] Error 1
So just remove the #if and #endif lines, but then 64-bit build warns:
mm/slab.c: In function `cache_alloc_debugcheck_after':
mm/slab.c:3156:6: warning: cast from pointer to integer of different size
mm/slab.c:3158:10: warning: format `%d' expects type `int', but argument
3 has type `long unsigned int'
Fix those with casts, whatever the actual type of ARCH_SLAB_MINALIGN.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Split cmpxchg_double_slab into two functions. One for the case where we know that
interrupts are disabled (and therefore the fallback does not need to disable
interrupts) and one for the other cases where fallback will also disable interrupts.
This fixes the issue that __slab_free called cmpxchg_double_slab in some scenarios
without disabling interrupts.
Tested-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
SPARSEMEM w/o VMEMMAP and DISCONTIGMEM, both used only on 32bit, use
sections array to map pfn to nid which is limited in granularity. If
NUMA nodes are laid out such that the mapping cannot be accurate, boot
will fail triggering BUG_ON() in mminit_verify_page_links().
On 32bit, it's 512MiB w/ PAE and SPARSEMEM. This seems to have been
granular enough until commit 2706a0bf7b (x86, NUMA: Enable
CONFIG_AMD_NUMA on 32bit too). Apparently, there is a machine which
aligns NUMA nodes to 128MiB and has only AMD NUMA but not SRAT. This
led to the following BUG_ON().
On node 0 totalpages: 2096615
DMA zone: 32 pages used for memmap
DMA zone: 0 pages reserved
DMA zone: 3927 pages, LIFO batch:0
Normal zone: 1740 pages used for memmap
Normal zone: 220978 pages, LIFO batch:31
HighMem zone: 16405 pages used for memmap
HighMem zone: 1853533 pages, LIFO batch:31
BUG: Int 6: CR2 (null)
EDI (null) ESI 00000002 EBP 00000002 ESP c1543ecc
EBX f2400000 EDX 00000006 ECX (null) EAX 00000001
err (null) EIP c16209aa CS 00000060 flg 00010002
Stack: f2400000 00220000 f7200800 c1620613 00220000 01000000 04400000 00238000
(null) f7200000 00000002 f7200b58 f7200800 c1620929 000375fe (null)
f7200b80 c16395f0 00200a02 f7200a80 (null) 000375fe 00000002 (null)
Pid: 0, comm: swapper Not tainted 2.6.39-rc5-00181-g2706a0b #17
Call Trace:
[<c136b1e5>] ? early_fault+0x2e/0x2e
[<c16209aa>] ? mminit_verify_page_links+0x12/0x42
[<c1620613>] ? memmap_init_zone+0xaf/0x10c
[<c1620929>] ? free_area_init_node+0x2b9/0x2e3
[<c1607e99>] ? free_area_init_nodes+0x3f2/0x451
[<c1601d80>] ? paging_init+0x112/0x118
[<c15f578d>] ? setup_arch+0x791/0x82f
[<c15f43d9>] ? start_kernel+0x6a/0x257
This patch implements node_map_pfn_alignment() which determines
maximum internode alignment and update numa_register_memblks() to
reject NUMA configuration if alignment exceeds the pfn -> nid mapping
granularity of the memory model as determined by PAGES_PER_SECTION.
This makes the problematic machine boot w/ flatmem by rejecting the
NUMA config and provides protection against crazy NUMA configurations.
Signed-off-by: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/20110712074534.GB2872@htj.dyndns.org
LKML-Reference: <20110628174613.GP478@escobedo.osrc.amd.com>
Reported-and-Tested-by: Hans Rosenfeld <hans.rosenfeld@amd.com>
Cc: Conny Seidel <conny.seidel@amd.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Add trace event balance_dirty_state for showing the global dirty page
counts and thresholds at each global_dirty_limits() invocation. This
will cover the callers throttle_vm_writeout(), over_bground_thresh()
and each balance_dirty_pages() loop.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
The max-pause limit helps to keep the sleep time inside
balance_dirty_pages() within MAX_PAUSE=200ms. The 200ms max sleep means
per task rate limit of 8pages/200ms=160KB/s when dirty exceeded, which
normally is enough to stop dirtiers from continue pushing the dirty
pages high, unless there are a sufficient large number of slow dirtiers
(eg. 500 tasks doing 160KB/s will still sum up to 80MB/s, exceeding the
write bandwidth of a slow disk and hence accumulating more and more dirty
pages).
The pass-good limit helps to let go of the good bdi's in the presence of
a blocked bdi (ie. NFS server not responding) or slow USB disk which for
some reason build up a large number of initial dirty pages that refuse
to go away anytime soon.
For example, given two bdi's A and B and the initial state
bdi_thresh_A = dirty_thresh / 2
bdi_thresh_B = dirty_thresh / 2
bdi_dirty_A = dirty_thresh / 2
bdi_dirty_B = dirty_thresh / 2
Then A get blocked, after a dozen seconds
bdi_thresh_A = 0
bdi_thresh_B = dirty_thresh
bdi_dirty_A = dirty_thresh / 2
bdi_dirty_B = dirty_thresh / 2
The (bdi_dirty_B < bdi_thresh_B) test is now useless and the dirty pages
will be effectively throttled by condition (nr_dirty < dirty_thresh).
This has two problems:
(1) we lose the protections for light dirtiers
(2) balance_dirty_pages() effectively becomes IO-less because the
(bdi_nr_reclaimable > bdi_thresh) test won't be true. This is good
for IO, but balance_dirty_pages() loses an important way to break
out of the loop which leads to more spread out throttle delays.
DIRTY_PASSGOOD_AREA can eliminate the above issues. The only problem is,
DIRTY_PASSGOOD_AREA needs to be defined as 2 to fully cover the above
example while this patch uses the more conservative value 8 so as not to
surprise people with too many dirty pages than expected.
The max-pause limit won't noticeably impact the speed dirty pages are
knocked down when there is a sudden drop of global/bdi dirty thresholds.
Because the heavy dirties will be throttled below 160KB/s which is slow
enough. It does help to avoid long dirty throttle delays and especially
will make light dirtiers more responsive.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
The start of a heavy weight application (ie. KVM) may instantly knock
down determine_dirtyable_memory() if the swap is not enabled or full.
global_dirty_limits() and bdi_dirty_limit() will in turn get global/bdi
dirty thresholds that are _much_ lower than the global/bdi dirty pages.
balance_dirty_pages() will then heavily throttle all dirtiers including
the light ones, until the dirty pages drop below the new dirty thresholds.
During this _deep_ dirty-exceeded state, the system may appear rather
unresponsive to the users.
About "deep" dirty-exceeded: task_dirty_limit() assigns 1/8 lower dirty
threshold to heavy dirtiers than light ones, and the dirty pages will
be throttled around the heavy dirtiers' dirty threshold and reasonably
below the light dirtiers' dirty threshold. In this state, only the heavy
dirtiers will be throttled and the dirty pages are carefully controlled
to not exceed the light dirtiers' dirty threshold. However if the
threshold itself suddenly drops below the number of dirty pages, the
light dirtiers will get heavily throttled.
So introduce global_dirty_limit for tracking the global dirty threshold
with policies
- follow downwards slowly
- follow up in one shot
global_dirty_limit can effectively mask out the impact of sudden drop of
dirtyable memory. It will be used in the next patch for two new type of
dirty limits. Note that the new dirty limits are not going to avoid
throttling the light dirtiers, but could limit their sleep time to 200ms.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Introduce
nr_dirty = NR_FILE_DIRTY + NR_WRITEBACK + NR_UNSTABLE_NFS
in order to simplify many tests in the following patches.
balance_dirty_pages() will eventually care only about the dirty sums
besides nr_writeback.
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Add a "BdiWriteBandwidth" entry and indent others in /debug/bdi/*/stats.
btw, increase digital field width to 10, for keeping the possibly
huge BdiWritten number aligned at least for desktop systems.
Impact: this could break user space tools if they are dumb enough to
depend on the number of white spaces.
CC: Theodore Ts'o <tytso@mit.edu>
CC: Jan Kara <jack@suse.cz>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
The estimation value will start from 100MB/s and adapt to the real
bandwidth in seconds.
It tries to update the bandwidth only when disk is fully utilized.
Any inactive period of more than one second will be skipped.
The estimated bandwidth will be reflecting how fast the device can
writeout when _fully utilized_, and won't drop to 0 when it goes idle.
The value will remain constant at disk idle time. At busy write time, if
not considering fluctuations, it will also remain high unless be knocked
down by possible concurrent reads that compete for the disk time and
bandwidth with async writes.
The estimation is not done purely in the flusher because there is no
guarantee for write_cache_pages() to return timely to update bandwidth.
The bdi->avg_write_bandwidth smoothing is very effective for filtering
out sudden spikes, however may be a little biased in long term.
The overheads are low because the bdi bandwidth update only occurs at
200ms intervals.
The 200ms update interval is suitable, because it's not possible to get
the real bandwidth for the instance at all, due to large fluctuations.
The NFS commits can be as large as seconds worth of data. One XFS
completion may be as large as half second worth of data if we are going
to increase the write chunk to half second worth of data. In ext4,
fluctuations with time period of around 5 seconds is observed. And there
is another pattern of irregular periods of up to 20 seconds on SSD tests.
That's why we are not only doing the estimation at 200ms intervals, but
also averaging them over a period of 3 seconds and then go further to do
another level of smoothing in avg_write_bandwidth.
CC: Li Shaohua <shaohua.li@intel.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Introduce the BDI_WRITTEN counter. It will be used for estimating the
bdi's write bandwidth.
Peter Zijlstra <a.p.zijlstra@chello.nl>:
Move BDI_WRITTEN accounting into __bdi_writeout_inc().
This will cover and fix fuse, which only calls bdi_writeout_inc().
CC: Michael Rubin <mrubin@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Pass struct wb_writeback_work all the way down to writeback_sb_inodes(),
and initialize the struct writeback_control there.
struct writeback_control is basically designed to control writeback of a
single file, but we keep abuse it for writing multiple files in
writeback_sb_inodes() and its callers.
It immediately clean things up, e.g. suddenly wbc.nr_to_write vs
work->nr_pages starts to make sense, and instead of saving and restoring
pages_skipped in writeback_sb_inodes it can always start with a clean
zero value.
It also makes a neat IO pattern change: large dirty files are now
written in the full 4MB writeback chunk size, rather than whatever
remained quota in wbc->nr_to_write.
Acked-by: Jan Kara <jack@suse.cz>
Proposed-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
remap_pfn_range() means map physical address pfn<<PAGE_SHIFT to user addr.
For nommu arch it's implemented by vma->vm_start = pfn << PAGE_SHIFT which
is wrong acroding the original meaning of this function. And some driver
developer using remap_pfn_range() with correct parameter will get
unexpected result because vm_start is changed. It should be implementd
like addr = pfn << PAGE_SHIFT but which is meanless on nommu arch, this
patch just make it simply return.
Parameter name and setting of vma->vm_flags also be fixed.
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Bob Liu <lliubbo@gmail.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
commit 889976dbcb ("memcg: reclaim memory from nodes in round-robin
order") adds an numa node round-robin for memcg. But the information is
updated once per 10sec.
This patch changes the update trigger from jiffies to memcg's event count.
After this patch, numa scan information will be updated when we see 1024
events of pagein/pageout under a memcg.
[akpm@linux-foundation.org: attempt to repair code layout]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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>
Now, in mem_cgroup_hierarchical_reclaim(), mem_cgroup_local_usage() is
used for checking whether the memcg contains reclaimable pages or not. If
no pages in it, the routine skips it.
But, mem_cgroup_local_usage() contains Unevictable pages and cannot handle
"noswap" condition correctly. This doesn't work on a swapless system.
This patch adds test_mem_cgroup_reclaimable() and replaces
mem_cgroup_local_usage(). test_mem_cgroup_reclaimable() see LRU counter
and returns correct answer to the caller. And this new function has
"noswap" argument and can see only FILE LRU if necessary.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix kerneldoc layout]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Ying Han <yinghan@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
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>
__tlb_remove_page() switches to a new batch page, but still checks space
in the old batch. This check always fails, and causes a forced tlb flush.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
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>
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>
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>
This fixes the following build breakage commit d6543e3 ("slub: Enable backtrace
for create/delete points"):
CC mm/slub.o
mm/slub.c: In function ‘set_track’:
mm/slub.c:428: error: storage size of ‘trace’ isn’t known
mm/slub.c:435: error: implicit declaration of function ‘save_stack_trace’
mm/slub.c:428: warning: unused variable ‘trace’
make[1]: *** [mm/slub.o] Error 1
make: *** [mm/slub.o] Error 2
Signed-off-by: Pekka Enberg <penberg@kernel.org>
slub checks for poison one byte by one, which is highly inefficient
and shows up frequently as a highest cpu-eater in perf top.
Joining reads gives nice speedup:
(Compiling some project with different options)
make -j12 make clean
slub_debug disabled: 1m 27s 1.2 s
slub_debug enabled: 1m 46s 7.6 s
slub_debug enabled + this patch: 1m 33s 3.2 s
check_bytes still shows up high, but not always at the top.
Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: linux-mm@kvack.org
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This is for tracking down suspect memory usage.
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
load_freelist is now only branched to only if there are objects available.
So no need to check the object variable for NULL.
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Make deactivation occur implicitly while checking out the current freelist.
This avoids one cmpxchg operation on a slab that is now fully in use.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Slub reloads the per cpu slab if the page does not satisfy the NUMA condition. Track
those reloads since doing so has a performance impact.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
We can avoid deactivate slab in special cases if we do the
deactivation of slabs in each code flow that leads to new_slab.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Disabling interrupts can be avoided now. However, list operation still require
disabling interrupts since allocations can occur from interrupt
contexts and there is no way to perform atomic list operations.
The acquition of the list_lock therefore has to disable interrupts as well.
Dropping interrupt handling significantly simplifies the slowpath.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
We will be calling free_debug_processing with interrupts disabled
in some case when the later patches are applied. Some of the
functions called by free_debug_processing expect interrupts to be
off.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Locking slabs is no longer necesary if the arch supports cmpxchg operations
and if no debuggin features are used on a slab. If the arch does not support
cmpxchg then we fallback to use the slab lock to do a cmpxchg like operation.
The patch also changes the lock order. Slab locks are subsumed to the node lock
now. With that approach slab_trylocking is no longer necessary.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Rework the allocation paths so that updates of the page freelist, frozen state
and number of objects use cmpxchg_double_slab().
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
We need more information about the slab for the cmpxchg implementation.
Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
The allocator fastpath rework does change the usage of the list_lock.
Remove the list_lock processing from the functions that hide them from the
critical sections and move them into those critical sections.
This in turn simplifies the support functions (no __ variant needed anymore)
and simplifies the lock handling on bootstrap.
Inline add_partial since it becomes pretty simple.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Add a function that operates on the second doubleword in the page struct
and manipulates the object counters, the freelist and the frozen attribute.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This is necessary because the frozen bit has to be handled in the same cmpxchg_double
with the freelist and the counters.
Signed-off-by: Christoph Lameter <cl@linux.com>
Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Do not use a page flag for the frozen bit. It needs to be part
of the state that is handled with cmpxchg_double(). So use a bit
in the counter struct in the page struct for that purpose.
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Do the irq handling in allocate_slab() instead of __slab_alloc().
__slab_alloc() is already cluttered and allocate_slab() is already
fiddling around with gfp flags.
v6->v7:
Only increment ORDER_FALLBACK if we get a page during fallback
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Commit d149e3b25d ("memcg: add the soft_limit reclaim in global direct
reclaim") adds a softlimit hook to shrink_zones(). By this, soft limit
is called as
try_to_free_pages()
do_try_to_free_pages()
shrink_zones()
mem_cgroup_soft_limit_reclaim()
Then, direct reclaim is memcg softlimit hint aware, now.
But, the memory cgroup's "limit" path can call softlimit shrinker.
try_to_free_mem_cgroup_pages()
do_try_to_free_pages()
shrink_zones()
mem_cgroup_soft_limit_reclaim()
This will cause a global reclaim when a memcg hits limit.
This is bug. soft_limit_reclaim() should be called when
scanning_global_lru(sc) == true.
And the commit adds a variable "total_scanned" for counting softlimit
scanned pages....it's not "total". This patch removes the variable and
update sc->nr_scanned instead of it. This will affect shrink_slab()'s
scan condition but, global LRU is scanned by softlimit and I think this
change makes sense.
TODO: avoid too much scanning of a zone when softlimit did enough work.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Ying Han <yinghan@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>
Under heavy memory and filesystem load, users observe the assertion
mapping->nrpages == 0 in end_writeback() trigger. This can be caused by
page reclaim reclaiming the last page from a mapping in the following
race:
CPU0 CPU1
...
shrink_page_list()
__remove_mapping()
__delete_from_page_cache()
radix_tree_delete()
evict_inode()
truncate_inode_pages()
truncate_inode_pages_range()
pagevec_lookup() - finds nothing
end_writeback()
mapping->nrpages != 0 -> BUG
page->mapping = NULL
mapping->nrpages--
Fix the problem by doing a reliable check of mapping->nrpages under
mapping->tree_lock in end_writeback().
Analyzed by Jay <jinshan.xiong@whamcloud.com>, lost in LKML, and dug out
by Miklos Szeredi <mszeredi@suse.de>.
Cc: Jay <jinshan.xiong@whamcloud.com>
Cc: Miklos Szeredi <mszeredi@suse.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We cannot take a mutex while holding a spinlock, so flip the order and
fix the locking documentation.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Although it is used (by i915) on nothing but tmpfs, read_cache_page_gfp()
is unsuited to tmpfs, because it inserts a page into pagecache before
calling the filesystem's ->readpage: tmpfs may have pages in swapcache
which only it knows how to locate and switch to filecache.
At present tmpfs provides a ->readpage method, and copes with this by
copying pages; but soon we can simplify it by removing its ->readpage.
Provide shmem_read_mapping_page_gfp() now, ready for that transition,
Export shmem_read_mapping_page_gfp() and add it to list in shmem_fs.h,
with shmem_read_mapping_page() inline for the common mapping_gfp case.
(shmem_read_mapping_page_gfp or shmem_read_cache_page_gfp? Generally the
read_mapping_page functions use the mapping's ->readpage, and the
read_cache_page functions use the supplied filler, so I think
read_cache_page_gfp was slightly misnamed.)
Signed-off-by: Hugh Dickins <hughd@google.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>
2.6.35's new truncate convention gave tmpfs the opportunity to control
its file truncation, no longer enforced from outside by vmtruncate().
We shall want to build upon that, to handle pagecache and swap together.
Slightly redefine the ->truncate_range interface: let it now be called
between the unmap_mapping_range()s, with the filesystem responsible for
doing the truncate_inode_pages_range() from it - just as the filesystem
is nowadays responsible for doing that from its ->setattr.
Let's rename shmem_notify_change() to shmem_setattr(). Instead of
calling the generic truncate_setsize(), bring that code in so we can
call shmem_truncate_range() - which will later be updated to perform its
own variant of truncate_inode_pages_range().
Remove the punch_hole unmap_mapping_range() from shmem_truncate_range():
now that the COW's unmap_mapping_range() comes after ->truncate_range,
there is no need to call it a third time.
Export shmem_truncate_range() and add it to the list in shmem_fs.h, so
that i915_gem_object_truncate() can call it explicitly in future; get
this patch in first, then update drm/i915 once this is available (until
then, i915 will just be doing the truncate_inode_pages() twice).
Though introduced five years ago, no other filesystem is implementing
->truncate_range, and its only other user is madvise(,,MADV_REMOVE): we
expect to convert it to fallocate(,FALLOC_FL_PUNCH_HOLE,,) shortly,
whereupon ->truncate_range can be removed from inode_operations -
shmem_truncate_range() will help i915 across that transition too.
Signed-off-by: Hugh Dickins <hughd@google.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>
Before adding any more global entry points into shmem.c, gather such
prototypes into shmem_fs.h. Remove mm's own declarations from swap.h,
but for now leave the ones in mm.h: because shmem_file_setup() and
shmem_zero_setup() are called from various places, and we should not
force other subsystems to update immediately.
Signed-off-by: Hugh Dickins <hughd@google.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>
You would expect to find vmtruncate_range() next to vmtruncate() in
mm/truncate.c: move it there.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 959ecc48fc ("mm/memory_hotplug.c: fix building of node hotplug
zonelist") does not protect the build_all_zonelists() call with
zonelists_mutex as needed. This can lead to races in constructing
zonelist ordering if a concurrent build is underway. Protecting this
with lock_memory_hotplug() is insufficient since zonelists can be
rebuild though sysfs as well.
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The error handling in mem_online_node() is incorrect: hotadd_new_pgdat()
returns NULL if the new pgdat could not have been allocated and a pointer
to it otherwise.
mem_online_node() should fail if hotadd_new_pgdat() fails, not the
inverse. This fixes an issue when memoryless nodes are not onlined and
their sysfs interface is not registered when their first cpu is brought
up.
The bug was introduced by commit cf23422b9d ("cpu/mem hotplug: enable
CPUs online before local memory online") iow v2.6.35.
Signed-off-by: David Rientjes <rientjes@google.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
At this point, tracehooks aren't useful to mainline kernel and mostly
just add an extra layer of obfuscation. Although they have comments,
without actual in-kernel users, it is difficult to tell what are their
assumptions and they're actually trying to achieve. To mainline
kernel, they just aren't worth keeping around.
This patch kills the following trivial tracehooks.
* Ones testing whether task is ptraced. Replace with ->ptrace test.
tracehook_expect_breakpoints()
tracehook_consider_ignored_signal()
tracehook_consider_fatal_signal()
* ptrace_event() wrappers. Call directly.
tracehook_report_exec()
tracehook_report_exit()
tracehook_report_vfork_done()
* ptrace_release_task() wrapper. Call directly.
tracehook_finish_release_task()
* noop
tracehook_prepare_release_task()
tracehook_report_death()
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
task_ptrace(task) simply dereferences task->ptrace and isn't even used
consistently only adding confusion. Kill it and directly access
->ptrace instead.
This doesn't introduce any behavior change.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This helps prevent tmpfs dirtiers from skewing the per-cpu bdp_ratelimits.
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Hugh Dickins points out that lockdep (correctly) spots a potential
deadlock on the anon_vma lock, because we now do a GFP_KERNEL allocation
of anon_vma_chain while doing anon_vma_clone(). The problem is that
page reclaim will want to take the anon_vma lock of any anonymous pages
that it will try to reclaim.
So re-organize the code in anon_vma_clone() slightly: first do just a
GFP_NOWAIT allocation, which will usually work fine. But if that fails,
let's just drop the lock and re-do the allocation, now with GFP_KERNEL.
End result: not only do we avoid the locking problem, this also ends up
getting better concurrency in case the allocation does need to block.
Tim Chen reports that with all these anon_vma locking tweaks, we're now
almost back up to the spinlock performance.
Reported-and-tested-by: Hugh Dickins <hughd@google.com>
Tested-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This matches the anon_vma_clone() case, and uses the same lock helper
functions. Because of the need to potentially release the anon_vma's,
it's a bit more complex, though.
We traverse the 'vma->anon_vma_chain' in two phases: the first loop gets
the anon_vma lock (with the helper function that only takes the lock
once for the whole loop), and removes any entries that don't need any
more processing.
The second phase just traverses the remaining list entries (without
holding the anon_vma lock), and does any actual freeing of the
anon_vma's that is required.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Tested-by: Hugh Dickins <hughd@google.com>
Tested-by: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In anon_vma_clone() we traverse the vma->anon_vma_chain of the source
vma, locking the anon_vma for each entry.
But they are all going to have the same root entry, which means that
we're locking and unlocking the same lock over and over again. Which is
expensive in locked operations, but can get _really_ expensive when that
root entry sees any kind of lock contention.
In fact, Tim Chen reports a big performance regression due to this: when
we switched to use a mutex instead of a spinlock, the contention case
gets much worse.
So to alleviate this all, this commit creates a small helper function
(lock_anon_vma_root()) that can be used to take the lock just once
rather than taking and releasing it over and over again.
We still have the same "take the lock and release" it behavior in the
exit path (in unlink_anon_vmas()), but that one is a bit harder to fix
since we're actually freeing the anon_vma entries as we go, and that
will touch the lock too.
Reported-and-tested-by: Tim Chen <tim.c.chen@linux.intel.com>
Tested-by: Hugh Dickins <hughd@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
swapcache will reach the below code path in migrate_page_move_mapping,
and swapcache is accounted as NR_FILE_PAGES but it's not accounted as
NR_SHMEM.
Hugh pointed out we must use PageSwapCache instead of comparing
mapping to &swapper_space, to avoid build failure with CONFIG_SWAP=n.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We have some users of this function that date back to before the vma
list was doubly linked, and just are silly. These days, you can find
the previous vma by just following the vma->vm_prev pointer.
In some cases you don't need any find_vma() lookup at all, and in other
cases you're better off with the regular "find_vma()" that uses the vma
cache front-end lookup.
Some "find_vma_prev()" users are still valid, though. For example, in
the case of a stack that grows up, it can be the case that we don't find
any 'vma' at all (because we're looking up an address that is past the
last vma), and that the stack that we want to grow is the 'prev' vma.
But that kind of special case aside, we generally should prefer to use
'find_vma()'.
Noticed due to a totally unrelated POWER memory corruption bug that just
happened to hit in 'find_vma_prev()' and made me go "Hmm - why are we
using that function here?".
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Andrea Righi reported a case where an exiting task can race against
ksmd::scan_get_next_rmap_item (http://lkml.org/lkml/2011/6/1/742) easily
triggering a NULL pointer dereference in ksmd.
ksm_scan.mm_slot == &ksm_mm_head with only one registered mm
CPU 1 (__ksm_exit) CPU 2 (scan_get_next_rmap_item)
list_empty() is false
lock slot == &ksm_mm_head
list_del(slot->mm_list)
(list now empty)
unlock
lock
slot = list_entry(slot->mm_list.next)
(list is empty, so slot is still ksm_mm_head)
unlock
slot->mm == NULL ... Oops
Close this race by revalidating that the new slot is not simply the list
head again.
Andrea's test case:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/mman.h>
#define BUFSIZE getpagesize()
int main(int argc, char **argv)
{
void *ptr;
if (posix_memalign(&ptr, getpagesize(), BUFSIZE) < 0) {
perror("posix_memalign");
exit(1);
}
if (madvise(ptr, BUFSIZE, MADV_MERGEABLE) < 0) {
perror("madvise");
exit(1);
}
*(char *)NULL = 0;
return 0;
}
Reported-by: Andrea Righi <andrea@betterlinux.com>
Tested-by: Andrea Righi <andrea@betterlinux.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Asynchronous compaction is used when promoting to huge pages. This is all
very nice but if there are a number of processes in compacting memory, a
large number of pages can be isolated. An "asynchronous" process can
stall for long periods of time as a result with a user reporting that
firefox can stall for 10s of seconds. This patch aborts asynchronous
compaction if too many pages are isolated as it's better to fail a
hugepage promotion than stall a process.
[minchan.kim@gmail.com: return COMPACT_PARTIAL for abort]
Reported-and-tested-by: Ury Stankevich <urykhy@gmail.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
Compaction works with two scanners, a migration and a free scanner. When
the scanners crossover, migration within the zone is complete. The
location of the scanner is recorded on each cycle to avoid excesive
scanning.
When a zone is small and mostly reserved, it's very easy for the migration
scanner to be close to the end of the zone. Then the following situation
can occurs
o migration scanner isolates some pages near the end of the zone
o free scanner starts at the end of the zone but finds that the
migration scanner is already there
o free scanner gets reinitialised for the next cycle as
cc->migrate_pfn + pageblock_nr_pages
moving the free scanner into the next zone
o migration scanner moves into the next zone
When this happens, NR_ISOLATED accounting goes haywire because some of the
accounting happens against the wrong zone. One zones counter remains
positive while the other goes negative even though the overall global
count is accurate. This was reported on X86-32 with !SMP because !SMP
allows the negative counters to be visible. The fact that it is the bug
should theoritically be possible there.
Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fragmentation_index() returns -1000 when the allocation might succeed
This doesn't match the comment and code in compaction_suitable(). I
thought compaction_suitable should return COMPACT_PARTIAL in -1000
case, because in this case allocation could succeed depending on
watermarks.
The impact of this is that compaction starts and compact_finished() is
called which rechecks the watermarks and the free lists. It should have
the same result in that compaction should not start but is more expensive.
Acked-by: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Shaohua Li <shaohua.li@intel.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>
Pages isolated for migration are accounted with the vmstat counters
NR_ISOLATE_[ANON|FILE]. Callers of migrate_pages() are expected to
increment these counters when pages are isolated from the LRU. Once the
pages have been migrated, they are put back on the LRU or freed and the
isolated count is decremented.
Memory failure is not properly accounting for pages it isolates causing
the NR_ISOLATED counters to be negative. On SMP builds, this goes
unnoticed as negative counters are treated as 0 due to expected per-cpu
drift. On UP builds, the counter is treated by too_many_isolated() as a
large value causing processes to enter D state during page reclaim or
compaction. This patch accounts for pages isolated by memory failure
correctly.
[mel@csn.ul.ie: rewrote changelog]
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Based on Michal Hocko's comment.
We are not draining per cpu cached charges during soft limit reclaim
because background reclaim doesn't care about charges. It tries to free
some memory and charges will not give any.
Cached charges might influence only selection of the biggest soft limit
offender but as the call is done only after the selection has been already
done it makes no change.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
For performance, memory cgroup caches some "charge" from res_counter into
per cpu cache. This works well but because it's cache, it needs to be
flushed in some cases. Typical cases are
1. when someone hit limit.
2. when rmdir() is called and need to charges to be 0.
But "1" has problem.
Recently, with large SMP machines, we see many kworker runs because of
flushing memcg's cache. Bad things in implementation are that even if a
cpu contains a cache for memcg not related to a memcg which hits limit,
drain code is called.
This patch does
A) check percpu cache contains a useful data or not.
B) check other asynchronous percpu draining doesn't run.
C) don't call local cpu callback.
(*)This patch avoid changing the calling condition with hard-limit.
When I run "cat 1Gfile > /dev/null" under 300M limit memcg,
[Before]
13767 kamezawa 20 0 98.6m 424 416 D 10.0 0.0 0:00.61 cat
58 root 20 0 0 0 0 S 0.6 0.0 0:00.09 kworker/2:1
60 root 20 0 0 0 0 S 0.6 0.0 0:00.08 kworker/4:1
4 root 20 0 0 0 0 S 0.3 0.0 0:00.02 kworker/0:0
57 root 20 0 0 0 0 S 0.3 0.0 0:00.05 kworker/1:1
61 root 20 0 0 0 0 S 0.3 0.0 0:00.05 kworker/5:1
62 root 20 0 0 0 0 S 0.3 0.0 0:00.05 kworker/6:1
63 root 20 0 0 0 0 S 0.3 0.0 0:00.05 kworker/7:1
[After]
2676 root 20 0 98.6m 416 416 D 9.3 0.0 0:00.87 cat
2626 kamezawa 20 0 15192 1312 920 R 0.3 0.0 0:00.28 top
1 root 20 0 19384 1496 1204 S 0.0 0.0 0:00.66 init
2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 0:00.00 ksoftirqd/0
4 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0
[akpm@linux-foundation.org: make percpu_charge_mutex static, tweak comments]
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Tested-by: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Hierarchical reclaim doesn't swap out if memsw and resource limits are
thye same (memsw_is_minimum == true) because we would hit mem+swap limit
anyway (during hard limit reclaim).
If it comes to the soft limit we shouldn't consider memsw_is_minimum at
all because it doesn't make much sense. Either the soft limit is bellow
the hard limit and then we cannot hit mem+swap limit or the direct reclaim
takes a precedence.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
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>
Commit 21a3c96468 ("memcg: allocate memory cgroup structures in local
nodes") makes page_cgroup allocation as NUMA aware. But that caused a
problem https://bugzilla.kernel.org/show_bug.cgi?id=36192.
The problem was getting a NID from invalid struct pages, which was not
initialized because it was out-of-node, out of [node_start_pfn,
node_end_pfn)
Now, with sparsemem, page_cgroup_init scans pfn from 0 to max_pfn. But
this may scan a pfn which is not on any node and can access memmap which
is not initialized.
This makes page_cgroup_init() for SPARSEMEM node aware and remove a code
to get nid from page->flags. (Then, we'll use valid NID always.)
[akpm@linux-foundation.org: try to fix up comments]
Signed-off-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>
Commit 406eb0c9ba ("memcg: add memory.numastat api for numa
statistics") adds memory.numa_stat file for memory cgroup. But the file
permissions are wrong.
[kamezawa@bluextal linux-2.6]$ ls -l /cgroup/memory/A/memory.numa_stat
---------- 1 root root 0 Jun 9 18:36 /cgroup/memory/A/memory.numa_stat
This patch fixes the permission as
[root@bluextal kamezawa]# ls -l /cgroup/memory/A/memory.numa_stat
-r--r--r-- 1 root root 0 Jun 10 16:49 /cgroup/memory/A/memory.numa_stat
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When 1GB hugepages are allocated on a system, free(1) reports less
available memory than what really is installed in the box. Also, if the
total size of hugepages allocated on a system is over half of the total
memory size, CommitLimit becomes a negative number.
The problem is that gigantic hugepages (order > MAX_ORDER) can only be
allocated at boot with bootmem, thus its frames are not accounted to
'totalram_pages'. However, they are accounted to hugetlb_total_pages()
What happens to turn CommitLimit into a negative number is this
calculation, in fs/proc/meminfo.c:
allowed = ((totalram_pages - hugetlb_total_pages())
* sysctl_overcommit_ratio / 100) + total_swap_pages;
A similar calculation occurs in __vm_enough_memory() in mm/mmap.c.
Also, every vm statistic which depends on 'totalram_pages' will render
confusing values, as if system were 'missing' some part of its memory.
Impact of this bug:
When gigantic hugepages are allocated and sysctl_overcommit_memory ==
OVERCOMMIT_NEVER. In a such situation, __vm_enough_memory() goes through
the mentioned 'allowed' calculation and might end up mistakenly returning
-ENOMEM, thus forcing the system to start reclaiming pages earlier than it
would be ususal, and this could cause detrimental impact to overall
system's performance, depending on the workload.
Besides the aforementioned scenario, I can only think of this causing
annoyances with memory reports from /proc/meminfo and free(1).
[akpm@linux-foundation.org: standardize comment layout]
Reported-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Rafael Aquini <aquini@linux.com>
Acked-by: Russ Anderson <rja@sgi.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
During memory hotplug we refresh zonelists when we online a page in a new
zone. It means that the node's zonelist is not initialized until pages
are onlined. So for example, "nid" passed by MEM_GOING_ONLINE notifier
will point to NODE_DATA(nid) which has no zone fallback list. Moreover,
if we hot-add cpu-only nodes, alloc_pages() will do no fallback.
This patch makes a zonelist when a new pgdata is available.
Note: in production, at fujitsu, memory should be onlined before cpu
and our server didn't have any memory-less nodes and had no problems.
But recent changes in MEM_GOING_ONLINE+page_cgroup
will access not initialized zonelist of node.
Anyway, there are memory-less node and we need some care.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
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>
Commit 56de7263fc ("mm: compaction: direct compact when a high-order
allocation fails") introduced a check for cc->order == -1 in
compact_finished. We should continue compacting in that case because
the request came from userspace and there is no particular order to
compact for. Similar check has been added by 82478fb7 (mm: compaction:
prevent division-by-zero during user-requested compaction) for
compaction_suitable.
The check is, however, done after zone_watermark_ok which uses order as a
right hand argument for shifts. Not only watermark check is pointless if
we can break out without it but it also uses 1 << -1 which is not well
defined (at least from C standard). Let's move the -1 check above
zone_watermark_ok.
[minchan.kim@gmail.com> - caught compaction_suitable]
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hioryu@jp.fujitsu.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>
Running a ktest.pl test, I hit the following bug on x86_32:
------------[ cut here ]------------
WARNING: at arch/x86/mm/highmem_32.c:81 __kunmap_atomic+0x64/0xc1()
Hardware name:
Modules linked in:
Pid: 93, comm: sh Not tainted 2.6.39-test+ #1
Call Trace:
[<c04450da>] warn_slowpath_common+0x7c/0x91
[<c042f5df>] ? __kunmap_atomic+0x64/0xc1
[<c042f5df>] ? __kunmap_atomic+0x64/0xc1^M
[<c0445111>] warn_slowpath_null+0x22/0x24
[<c042f5df>] __kunmap_atomic+0x64/0xc1
[<c04d4a22>] unmap_vmas+0x43a/0x4e0
[<c04d9065>] exit_mmap+0x91/0xd2
[<c0443057>] mmput+0x43/0xad
[<c0448358>] exit_mm+0x111/0x119
[<c044855f>] do_exit+0x1ff/0x5fa
[<c0454ea2>] ? set_current_blocked+0x3c/0x40
[<c0454f24>] ? sigprocmask+0x7e/0x8e
[<c0448b55>] do_group_exit+0x65/0x88
[<c0448b90>] sys_exit_group+0x18/0x1c
[<c0c3915f>] sysenter_do_call+0x12/0x38
---[ end trace 8055f74ea3c0eb62 ]---
Running a ktest.pl git bisect, found the culprit: commit e303297e6c
("mm: extended batches for generic mmu_gather")
But although this was the commit triggering the bug, it was not the one
originally responsible for the bug. That was commit d16dfc550f ("mm:
mmu_gather rework").
The code in zap_pte_range() has something that looks like the following:
pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
do {
[...]
} while (pte++, addr += PAGE_SIZE, addr != end);
pte_unmap_unlock(pte - 1, ptl);
The pte starts off pointing at the first element in the page table
directory that was returned by the pte_offset_map_lock(). When it's done
with the page, pte will be pointing to anything between the next entry and
the first entry of the next page inclusive. By doing a pte - 1, this puts
the pte back onto the original page, which is all that pte_unmap_unlock()
needs.
In most archs (64 bit), this is not an issue as the pte is ignored in the
pte_unmap_unlock(). But on 32 bit archs, where things may be kmapped, it
is essential that the pte passed to pte_unmap_unlock() resides on the same
page that was given by pte_offest_map_lock().
The problem came in d16dfc55 ("mm: mmu_gather rework") where it introduced
a "break;" from the while loop. This alone did not seem to easily trigger
the bug. But the modifications made by e303297e6 caused that "break;" to
be hit on the first iteration, before the pte++.
The pte not being incremented will now cause pte_unmap_unlock(pte - 1) to
be pointing to the previous page. This will cause the wrong page to be
unmapped, and also trigger the warning above.
The simple solution is to just save the pointer given by
pte_offset_map_lock() and use it in the unlock.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Hugh Dickins <hughd@google.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>
While testing for memcg aware swap token, I observed a swap token was
often grabbed an intermittent running process (eg init, auditd) and they
never release a token.
Why?
Some processes (eg init, auditd, audispd) wake up when a process exiting.
And swap token can be get first page-in process when a process exiting
makes no swap token owner. Thus such above intermittent running process
often get a token.
And currently, swap token priority is only decreased at page fault path.
Then, if the process sleep immediately after to grab swap token, the swap
token priority never be decreased. That's obviously undesirable.
This patch implement very poor (and lightweight) priority aging. It only
be affect to the above corner case and doesn't change swap tendency
workload performance (eg multi process qsbench load)
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Rik van Riel <riel@redhat.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>
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>
Fix new kernel-doc warnings in mm/memory.c:
Warning(mm/memory.c:1327): No description found for parameter 'tlb'
Warning(mm/memory.c:1327): Excess function parameter 'tlbp' description in 'unmap_vmas'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes noticed the vmstat update is already taken care of by
khugepaged_alloc_hugepage() internally. The only places that are required
to update the vmstat are the callers of alloc_hugepage (callers of
khugepaged_alloc_hugepage aren't).
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Johannes Weiner <jweiner@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.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>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6:
SLAB: Record actual last user of freed objects.
slub: always align cpu_slab to honor cmpxchg_double requirement
* 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
vfs: make unlink() and rmdir() return ENOENT in preference to EROFS
lmLogOpen() broken failure exit
usb: remove bad dput after dentry_unhash
more conservative S_NOSEC handling
This avoids unnecessary checks and dirty throttling on tmpfs/ramfs.
Notes about the tmpfs/ramfs behavior changes:
As for 2.6.36 and older kernels, the tmpfs writes will sleep inside
balance_dirty_pages() as long as we are over the (dirty+background)/2
global throttle threshold. This is because both the dirty pages and
threshold will be 0 for tmpfs/ramfs. Hence this test will always
evaluate to TRUE:
dirty_exceeded =
(bdi_nr_reclaimable + bdi_nr_writeback >= bdi_thresh)
|| (nr_reclaimable + nr_writeback >= dirty_thresh);
For 2.6.37, someone complained that the current logic does not allow the
users to set vm.dirty_ratio=0. So commit 4cbec4c8b9 changed the test to
dirty_exceeded =
(bdi_nr_reclaimable + bdi_nr_writeback > bdi_thresh)
|| (nr_reclaimable + nr_writeback > dirty_thresh);
So 2.6.37 will behave differently for tmpfs/ramfs: it will never get
throttled unless the global dirty threshold is exceeded (which is very
unlikely to happen; once happen, will block many tasks).
I'd say that the 2.6.36 behavior is very bad for tmpfs/ramfs. It means
for a busy writing server, tmpfs write()s may get livelocked! The
"inadvertent" throttling can hardly bring help to any workload because
of its "either no throttling, or get throttled to death" property.
So based on 2.6.37, this patch won't bring more noticeable changes.
CC: Hugh Dickins <hughd@google.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Clarify the bdi_dirty_limit() comment.
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Split the global inode_wb_list_lock into a per-bdi_writeback list_lock,
as it's currently the most contended lock in the system for metadata
heavy workloads. It won't help for single-filesystem workloads for
which we'll need the I/O-less balance_dirty_pages, but at least we
can dedicate a cpu to spinning on each bdi now for larger systems.
Based on earlier patches from Nick Piggin and Dave Chinner.
It reduces lock contentions to 1/4 in this test case:
10 HDD JBOD, 100 dd on each disk, XFS, 6GB ram
lock_stat version 0.3
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
class name con-bounces contentions waittime-min waittime-max waittime-total acq-bounces acquisitions holdtime-min holdtime-max holdtime-total
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
vanilla 2.6.39-rc3:
inode_wb_list_lock: 42590 44433 0.12 147.74 144127.35 252274 886792 0.08 121.34 917211.23
------------------
inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85
inode_wb_list_lock 34 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49
inode_wb_list_lock 12893 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0
inode_wb_list_lock 10702 [<ffffffff8115afef>] writeback_single_inode+0x16d/0x20a
------------------
inode_wb_list_lock 2 [<ffffffff81165da5>] bdev_inode_switch_bdi+0x29/0x85
inode_wb_list_lock 19 [<ffffffff8115bd0b>] inode_wb_list_del+0x22/0x49
inode_wb_list_lock 5550 [<ffffffff8115bb53>] __mark_inode_dirty+0x170/0x1d0
inode_wb_list_lock 8511 [<ffffffff8115b4ad>] writeback_sb_inodes+0x10f/0x157
2.6.39-rc3 + patch:
&(&wb->list_lock)->rlock: 11383 11657 0.14 151.69 40429.51 90825 527918 0.11 145.90 556843.37
------------------------
&(&wb->list_lock)->rlock 10 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86
&(&wb->list_lock)->rlock 1493 [<ffffffff8115b1ed>] writeback_inodes_wb+0x3d/0x150
&(&wb->list_lock)->rlock 3652 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f
&(&wb->list_lock)->rlock 1412 [<ffffffff8115a38e>] writeback_single_inode+0x17f/0x223
------------------------
&(&wb->list_lock)->rlock 3 [<ffffffff8110b5af>] bdi_lock_two+0x46/0x4b
&(&wb->list_lock)->rlock 6 [<ffffffff8115b189>] inode_wb_list_del+0x5f/0x86
&(&wb->list_lock)->rlock 2061 [<ffffffff8115af97>] __mark_inode_dirty+0x173/0x1cf
&(&wb->list_lock)->rlock 2629 [<ffffffff8115a8e9>] writeback_sb_inodes+0x123/0x16f
hughd@google.com: fix recursive lock when bdi_lock_two() is called with new the same as old
akpm@linux-foundation.org: cleanup bdev_inode_switch_bdi() comment
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
sync(2) is performed in two stages: the WB_SYNC_NONE sync and the
WB_SYNC_ALL sync. Identify the first stage with .tagged_writepages and
do livelock prevention for it, too.
Jan's commit f446daaea9 ("mm: implement writeback livelock avoidance
using page tagging") is a partial fix in that it only fixed the
WB_SYNC_ALL phase livelock.
Although ext4 is tested to no longer livelock with commit f446daaea9,
it may due to some "redirty_tail() after pages_skipped" effect which
is by no means a guarantee for _all_ the file systems.
Note that writeback_inodes_sb() is called by not only sync(), they are
treated the same because the other callers also need livelock prevention.
Impact: It changes the order in which pages/inodes are synced to disk.
Now in the WB_SYNC_NONE stage, it won't proceed to write the next inode
until finished with the current inode.
Acked-by: Jan Kara <jack@suse.cz>
CC: Dave Chinner <david@fromorbit.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Doing a ktest.pl randconfig, I stumbled across the following bug
on boot up:
------------[ cut here ]------------
WARNING: at /home/rostedt/work/autotest/nobackup/linux-test.git/kernel/lockdep.c:2649 lockdep_trace_alloc+0xed/0x100()
Hardware name:
Modules linked in:
Pid: 0, comm: swapper Not tainted 3.0.0-rc1-test-00054-g1d68b67 #1
Call Trace:
[<ffffffff810626ad>] warn_slowpath_common+0xad/0xf0
[<ffffffff8106270a>] warn_slowpath_null+0x1a/0x20
[<ffffffff810b537d>] lockdep_trace_alloc+0xed/0x100
[<ffffffff81182fb0>] __kmalloc_node+0x30/0x2f0
[<ffffffff81153eda>] pcpu_mem_alloc+0x13a/0x180
[<ffffffff82be022c>] percpu_init_late+0x48/0xc2
[<ffffffff82bd630c>] ? mem_init+0xd8/0xe3
[<ffffffff82bbcc73>] start_kernel+0x1c2/0x449
[<ffffffff82bbc35c>] x86_64_start_reservations+0x163/0x167
[<ffffffff82bbc493>] x86_64_start_kernel+0x133/0x142^M
---[ end trace a7919e7f17c0a725 ]---
Then I ran a ktest.pl config_bisect and it came up with this config
as the problem:
CONFIG_SLOB
Looking at what is different between SLOB and SLAB and SLUB, I found
that the gfp flags are masked against gfp_allowed_mask in
SLAB and SLUB, but not SLOB.
On boot up, interrupts are disabled and lockdep will warn if some flags
are set in gfp and interrupts are disabled. But these flags are masked
off with the gfp_allowed_mask during boot. Because SLOB does not
mask the flags against gfp_allowed_mask it triggers the warn on.
Adding this mask fixes the bug. I also found that kmem_cache_alloc_node()
was missing both the mask and the lockdep check, and that was added too.
Acked-by: Matt Mackall <mpm@selenic.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Al Viro observes that in the hugetlb case, handle_mm_fault() may return
a value of the kind ENOSPC when its caller is expecting a value of the
kind VM_FAULT_SIGBUS: fix alloc_huge_page()'s failure returns.
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Caching "we have already removed suid/caps" was overenthusiastic as merged.
On network filesystems we might have had suid/caps set on another client,
silently picked by this client on revalidate, all of that *without* clearing
the S_NOSEC flag.
AFAICS, the only reasonably sane way to deal with that is
* new superblock flag; unless set, S_NOSEC is not going to be set.
* local block filesystems set it in their ->mount() (more accurately,
mount_bdev() does, so does btrfs ->mount(), users of mount_bdev() other than
local block ones clear it)
* if any network filesystem (or a cluster one) wants to use S_NOSEC,
it'll need to set MS_NOSEC in sb->s_flags *AND* take care to clear S_NOSEC when
inode attribute changes are picked from other clients.
It's not an earth-shattering hole (anybody that can set suid on another client
will almost certainly be able to write to the file before doing that anyway),
but it's a bug that needs fixing.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently, when using CONFIG_DEBUG_SLAB, we put in kfree() or
kmem_cache_free() as the last user of free objects, which is not
very useful, so change it to the caller of those functions instead.
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
On an architecture without CMPXCHG_LOCAL but with DEBUG_VM enabled,
the VM_BUG_ON() in __pcpu_double_call_return_bool() will cause an early
panic during boot unless we always align cpu_slab properly.
In principle we could remove the alignment-testing VM_BUG_ON() for
architectures that don't have CMPXCHG_LOCAL, but leaving it in means
that new code will tend not to break x86 even if it is introduced
on another platform, and it's low cost to require alignment.
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This reverts commit a197b59ae6.
As rmk says:
"Commit a197b59ae6 (mm: fail GFP_DMA allocations when ZONE_DMA is not
configured) is causing regressions on ARM with various drivers which
use GFP_DMA.
The behaviour up until now has been to silently ignore that flag when
CONFIG_ZONE_DMA is not enabled, and to allocate from the normal zone.
However, as a result of the above commit, such allocations now fail
which causes drivers to fail. These are regressions compared to the
previous kernel version."
so just revert it.
Requested-by: Russell King <linux@arm.linux.org.uk>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Inspired by an analysis from Hugh on why again all this doesn't explode
in our face.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
On one machine I've been getting hangs, a page fault's anon_vma_prepare()
waiting in anon_vma_lock(), other processes waiting for that page's lock.
This is a replay of last year's f18194275c "mm: fix hang on
anon_vma->root->lock".
The new page_lock_anon_vma() places too much faith in its refcount: when
it has acquired the mutex_trylock(), it's possible that a racing task in
anon_vma_alloc() has just reallocated the struct anon_vma, set refcount
to 1, and is about to reset its anon_vma->root.
Fix this by saving anon_vma->root, and relying on the usual page_mapped()
check instead of a refcount check: if page is still mapped, the anon_vma
is still ours; if page is not still mapped, we're no longer interested.
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I've hit the "address >= vma->vm_end" check in do_page_add_anon_rmap()
just once. The stack showed khugepaged allocation trying to compact
pages: the call to page_add_anon_rmap() coming from remove_migration_pte().
That path holds anon_vma lock, but does not hold mmap_sem: it can
therefore race with a split_vma(), and in commit 5f70b962cc "mmap:
avoid unnecessary anon_vma lock" we just took away the anon_vma lock
protection when adjusting vma->vm_end.
I don't think that particular BUG_ON ever caught anything interesting,
so better replace it by a comment, than reinstate the anon_vma locking.
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While running fsx on tmpfs with a memhog then swapoff, swapoff was hanging
(interruptibly), repeatedly failing to locate the owner of a 0xff entry in
the swap_map.
Although shmem_writepage() does abandon when it sees incoming page index
is beyond eof, there was still a window in which shmem_truncate_range()
could come in between writepage's dropping lock and updating swap_map,
find the half-completed swap_map entry, and in trying to free it,
leave it in a state that swap_shmem_alloc() could not correct.
Arguably a bug in __swap_duplicate()'s and swap_entry_free()'s handling
of the different cases, but easiest to fix by moving swap_shmem_alloc()
under cover of the lock.
More interesting than the bug: it's been there since 2.6.33, why could
I not see it with earlier kernels? The mmotm of two weeks ago seems to
have some magic for generating races, this is just one of three I found.
With yesterday's git I first saw this in mainline, bisected in search of
that magic, but the easy reproducibility evaporated. Oh well, fix the bug.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (36 commits)
Cache xattr security drop check for write v2
fs: block_page_mkwrite should wait for writeback to finish
mm: Wait for writeback when grabbing pages to begin a write
configfs: remove unnecessary dentry_unhash on rmdir, dir rename
fat: remove unnecessary dentry_unhash on rmdir, dir rename
hpfs: remove unnecessary dentry_unhash on rmdir, dir rename
minix: remove unnecessary dentry_unhash on rmdir, dir rename
fuse: remove unnecessary dentry_unhash on rmdir, dir rename
coda: remove unnecessary dentry_unhash on rmdir, dir rename
afs: remove unnecessary dentry_unhash on rmdir, dir rename
affs: remove unnecessary dentry_unhash on rmdir, dir rename
9p: remove unnecessary dentry_unhash on rmdir, dir rename
ncpfs: fix rename over directory with dangling references
ncpfs: document dentry_unhash usage
ecryptfs: remove unnecessary dentry_unhash on rmdir, dir rename
hostfs: remove unnecessary dentry_unhash on rmdir, dir rename
hfsplus: remove unnecessary dentry_unhash on rmdir, dir rename
hfs: remove unnecessary dentry_unhash on rmdir, dir rename
omfs: remove unnecessary dentry_unhash on rmdir, dir rneame
udf: remove unnecessary dentry_unhash from rmdir, dir rename
...
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (25 commits)
perf: Fix SIGIO handling
perf top: Don't stop if no kernel symtab is found
perf top: Handle kptr_restrict
perf top: Remove unused macro
perf events: initialize fd array to -1 instead of 0
perf tools: Make sure kptr_restrict warnings fit 80 col terms
perf tools: Fix build on older systems
perf symbols: Handle /proc/sys/kernel/kptr_restrict
perf: Remove duplicate headers
ftrace: Add internal recursive checks
tracing: Update btrfs's tracepoints to use u64 interface
tracing: Add __print_symbolic_u64 to avoid warnings on 32bit machine
ftrace: Set ops->flag to enabled even on static function tracing
tracing: Have event with function tracer check error return
ftrace: Have ftrace_startup() return failure code
jump_label: Check entries limit in __jump_label_update
ftrace/recordmcount: Avoid STT_FUNC symbols as base on ARM
scripts/tags.sh: Add magic for trace-events for etags too
scripts/tags.sh: Fix ctags for DEFINE_EVENT()
x86/ftrace: Fix compiler warning in ftrace.c
...
Some recent benchmarking on btrfs showed that a major scaling bottleneck
on large systems on btrfs is currently the xattr lookup on every write.
Why xattr lookup on every write I hear you ask?
write wants to drop suid and security related xattrs that could set o
capabilities for executables. To do that it currently looks up
security.capability on EVERY write (even for non executables) to decide
whether to drop it or not.
In btrfs this causes an additional tree walk, hitting some per file system
locks and quite bad scalability. In a simple read workload on a 8S
system I saw over 90% CPU time in spinlocks related to that.
Chris Mason tells me this is also a problem in ext4, where it hits
the global mbcache lock.
This patch adds a simple per inode to avoid this problem. We only
do the lookup once per file and then if there is no xattr cache
the decision. All xattr changes clear the flag.
I also used the same flag to avoid the suid check, although
that one is pretty cheap.
A file system can also set this flag when it creates the inode,
if it has a cheap way to do so. This is done for some common file systems
in followon patches.
With this patch a major part of the lock contention disappears
for btrfs. Some testing on smaller systems didn't show significant
performance changes, but at least it helps the larger systems
and is generally more efficient.
v2: Rename is_sgid. add file system helper.
Cc: chris.mason@oracle.com
Cc: josef@redhat.com
Cc: viro@zeniv.linux.org.uk
Cc: agruen@linbit.com
Cc: Serge E. Hallyn <serue@us.ibm.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When grabbing a page for a buffered IO write, the mm should wait for writeback
on the page to complete so that the page does not become writable during the IO
operation. This change is needed to provide page stability during writes for
all filesystems.
Signed-off-by: Darrick J. Wong <djwong@us.ibm.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* 'upstream/tidy-xen-mmu-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen:
xen: fix compile without CONFIG_XEN_DEBUG_FS
Use arbitrary_virt_to_machine() to deal with ioremapped pud updates.
Use arbitrary_virt_to_machine() to deal with ioremapped pmd updates.
xen/mmu: remove all ad-hoc stats stuff
xen: use normal virt_to_machine for ptes
xen: make a pile of mmu pvop functions static
vmalloc: remove vmalloc_sync_all() from alloc_vm_area()
xen: condense everything onto xen_set_pte
xen: use mmu_update for xen_set_pte_at()
xen: drop all the special iomap pte paths.
Two new stats in per-memcg memory.stat which tracks the number of page
faults and number of major page faults.
"pgfault"
"pgmajfault"
They are different from "pgpgin"/"pgpgout" stat which count number of
pages charged/discharged to the cgroup and have no meaning of reading/
writing page to disk.
It is valuable to track the two stats for both measuring application's
performance as well as the efficiency of the kernel page reclaim path.
Counting pagefaults per process is useful, but we also need the aggregated
value since processes are monitored and controlled in cgroup basis in
memcg.
Functional test: check the total number of pgfault/pgmajfault of all
memcgs and compare with global vmstat value:
$ cat /proc/vmstat | grep fault
pgfault 1070751
pgmajfault 553
$ cat /dev/cgroup/memory.stat | grep fault
pgfault 1071138
pgmajfault 553
total_pgfault 1071142
total_pgmajfault 553
$ cat /dev/cgroup/A/memory.stat | grep fault
pgfault 199
pgmajfault 0
total_pgfault 199
total_pgmajfault 0
Performance test: run page fault test(pft) wit 16 thread on faulting in
15G anon pages in 16G container. There is no regression noticed on the
"flt/cpu/s"
Sample output from pft:
TAG pft:anon-sys-default:
Gb Thr CLine User System Wall flt/cpu/s fault/wsec
15 16 1 0.67s 233.41s 14.76s 16798.546 266356.260
+-------------------------------------------------------------------------+
N Min Max Median Avg Stddev
x 10 16682.962 17344.027 16913.524 16928.812 166.5362
+ 10 16695.568 16923.896 16820.604 16824.652 84.816568
No difference proven at 95.0% confidence
[akpm@linux-foundation.org: fix build]
[hughd@google.com: shmem fix]
Signed-off-by: Ying Han <yinghan@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.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>
The new API exports numa_maps per-memcg basis. This is a piece of useful
information where it exports per-memcg page distribution across real numa
nodes.
One of the usecases is evaluating application performance by combining
this information w/ the cpu allocation to the application.
The output of the memory.numastat tries to follow w/ simiar format of
numa_maps like:
total=<total pages> N0=<node 0 pages> N1=<node 1 pages> ...
file=<total file pages> N0=<node 0 pages> N1=<node 1 pages> ...
anon=<total anon pages> N0=<node 0 pages> N1=<node 1 pages> ...
unevictable=<total anon pages> N0=<node 0 pages> N1=<node 1 pages> ...
And we have per-node:
total = file + anon + unevictable
$ cat /dev/cgroup/memory/memory.numa_stat
total=250020 N0=87620 N1=52367 N2=45298 N3=64735
file=225232 N0=83402 N1=46160 N2=40522 N3=55148
anon=21053 N0=3424 N1=6207 N2=4776 N3=6646
unevictable=3735 N0=794 N1=0 N2=0 N3=2941
Signed-off-by: Ying Han <yinghan@google.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
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>
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>
If the memcg reclaim code detects the target memcg below its limit it
exits and returns a guaranteed non-zero value so that the charge is
retried.
Nowadays, the charge side checks the memcg limit itself and does not rely
on this non-zero return value trick.
This patch removes it. The reclaim code will now always return the true
number of pages it reclaimed on its own.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Rik van Riel<riel@redhat.com>
Acked-by: Ying Han<yinghan@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mgorman@suse.de>
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>
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>
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>
Move page-freeing code out of swap_cgroup_mutex in the hope that it could
reduce few of theoretical contentions between swapons and/or swapoffs.
This is just a cleanup, no functional changes.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It allocated one more page than necessary if @max_pages was a multiple of
SC_PER_PAGE.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Michal Hocko <mhocko@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit ca371c0d7e ("memcg: fix page_cgroup fatal error in FLATMEM")
removes call to alloc_bootmem() in the function so that it can be marked
as __meminit to reduce memory usage when MEMORY_HOTPLUG=n.
Also as the new helper function alloc_page_cgroup() is called only in the
function, it should be marked too.
Signed-off-by: Namhyung Kim <namhyung@gmail.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
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>
next_mz is assigned to NULL if __mem_cgroup_largest_soft_limit_node
selects the same mz. This doesn't make much sense as we assign to the
variable right in the next loop.
Compiler will probably optimize this out but it is little bit confusing
for the code reading.
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.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>
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>
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>
Add cgroup subsystem callbacks for per-thread attachment in atomic contexts
Add can_attach_task(), pre_attach(), and attach_task() as new callbacks
for cgroups's subsystem interface. Unlike can_attach and attach, these
are for per-thread operations, to be called potentially many times when
attaching an entire threadgroup.
Also, the old "bool threadgroup" interface is removed, as replaced by
this. All subsystems are modified for the new interface - of note is
cpuset, which requires from/to nodemasks for attach to be globally scoped
(though per-cpuset would work too) to persist from its pre_attach to
attach_task and attach.
This is a pre-patch for cgroup-procs-writable.patch.
Signed-off-by: Ben Blum <bblum@andrew.cmu.edu>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Reviewed-by: Paul Menage <menage@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem:
xen: cleancache shim to Xen Transcendent Memory
ocfs2: add cleancache support
ext4: add cleancache support
btrfs: add cleancache support
ext3: add cleancache support
mm/fs: add hooks to support cleancache
mm: cleancache core ops functions and config
fs: add field to superblock to support cleancache
mm/fs: cleancache documentation
Fix up trivial conflict in fs/btrfs/extent_io.c due to includes
The type of vma->vm_flags is 'unsigned long'. Neither 'int' nor
'unsigned int'. This patch fixes such misuse.
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
[ Changed to use a typedef - we'll extend it to cover more cases
later, since there has been discussion about making it a 64-bit
type.. - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fourth patch of eight in this cleancache series provides the
core hooks in VFS for: initializing cleancache per filesystem;
capturing clean pages reclaimed by page cache; attempting to get
pages from cleancache before filesystem read; and ensuring coherency
between pagecache, disk, and cleancache. Note that the placement
of these hooks was stable from 2.6.18 to 2.6.38; a minor semantic
change was required due to a patchset in 2.6.39.
All hooks become no-ops if CONFIG_CLEANCACHE is unset, or become
a check of a boolean global if CONFIG_CLEANCACHE is set but no
cleancache "backend" has claimed cleancache_ops.
Details and a FAQ can be found in Documentation/vm/cleancache.txt
[v8: minchan.kim@gmail.com: adapt to new remove_from_page_cache function]
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Jeremy Fitzhardinge <jeremy@goop.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik Van Riel <riel@redhat.com>
Cc: Jan Beulich <JBeulich@novell.com>
Cc: Andreas Dilger <adilger@sun.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Cc: Nitin Gupta <ngupta@vflare.org>
This third patch of eight in this cleancache series provides
the core code for cleancache that interfaces between the hooks in
VFS and individual filesystems and a cleancache backend. It also
includes build and config patches.
Two new files are added: mm/cleancache.c and include/linux/cleancache.h.
Note that CONFIG_CLEANCACHE can default to on; in systems that do
not provide a cleancache backend, all hooks devolve to a simple
check of a global enable flag, so performance impact should
be negligible but can be reduced to zero impact if config'ed off.
However for this first commit, it defaults to off.
Details and a FAQ can be found in Documentation/vm/cleancache.txt
Credits: Cleancache_ops design derived from Jeremy Fitzhardinge
design for tmem
[v8: dan.magenheimer@oracle.com: fix exportfs call affecting btrfs]
[v8: akpm@linux-foundation.org: use static inline function, not macro]
[v7: dan.magenheimer@oracle.com: cleanup sysfs and remove cleancache prefix]
[v6: JBeulich@novell.com: robustly handle buggy fs encode_fh actor definition]
[v5: jeremy@goop.org: clean up global usage and static var names]
[v5: jeremy@goop.org: simplify init hook and any future fs init changes]
[v5: hch@infradead.org: cleaner non-global interface for ops registration]
[v4: adilger@sun.com: interface must support exportfs FS's]
[v4: hch@infradead.org: interface must support 64-bit FS on 32-bit kernel]
[v3: akpm@linux-foundation.org: use one ops struct to avoid pointer hops]
[v3: akpm@linux-foundation.org: document and ensure PageLocked reqts are met]
[v3: ngupta@vflare.org: fix success/fail codes, change funcs to void]
[v2: viro@ZenIV.linux.org.uk: use sane types]
Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com>
Reviewed-by: Jeremy Fitzhardinge <jeremy@goop.org>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Nitin Gupta <ngupta@vflare.org>
Acked-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Andreas Dilger <adilger@sun.com>
Acked-by: Jan Beulich <JBeulich@novell.com>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik Van Riel <riel@redhat.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <joel.becker@oracle.com>
Commit a71ae47a2c ("slub: Fix double bit unlock in debug mode")
removed the only goto to this label, resulting in
mm/slub.c: In function '__slab_alloc':
mm/slub.c:1834: warning: label 'unlock_out' defined but not used
fixed trivially by the removal of the label itself too.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The functions probe_kernel_write() and probe_kernel_read() do not modify
the src pointer. Allow const pointers to be passed in without the need
of a typecast.
Acked-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1305824936.1465.4.camel@gandalf.stny.rr.com
* 'for-2.6.40/core' of git://git.kernel.dk/linux-2.6-block: (40 commits)
cfq-iosched: free cic_index if cfqd allocation fails
cfq-iosched: remove unused 'group_changed' in cfq_service_tree_add()
cfq-iosched: reduce bit operations in cfq_choose_req()
cfq-iosched: algebraic simplification in cfq_prio_to_maxrq()
blk-cgroup: Initialize ioc->cgroup_changed at ioc creation time
block: move bd_set_size() above rescan_partitions() in __blkdev_get()
block: call elv_bio_merged() when merged
cfq-iosched: Make IO merge related stats per cpu
cfq-iosched: Fix a memory leak of per cpu stats for root group
backing-dev: Kill set but not used var in bdi_debug_stats_show()
block: get rid of on-stack plugging debug checks
blk-throttle: Make no throttling rule group processing lockless
blk-cgroup: Make cgroup stat reset path blkg->lock free for dispatch stats
blk-cgroup: Make 64bit per cpu stats safe on 32bit arch
blk-throttle: Make dispatch stats per cpu
blk-throttle: Free up a group only after one rcu grace period
blk-throttle: Use helper function to add root throtl group to lists
blk-throttle: Introduce a helper function to fill in device details
blk-throttle: Dynamically allocate root group
blk-cgroup: Allow sleeping while dynamically allocating a group
...
Currently on nommu arch mmap(),mremap() and munmap() doesn't do
page_align() which isn't consist with mmu arch and cause some issues.
First, some drivers' mmap() function depends on vma->vm_end - vma->start
is page aligned which is true on mmu arch but not on nommu. eg: uvc
camera driver.
Second munmap() may return -EINVAL[split file] error in cases when end is
not page aligned(passed into from userspace) but vma->vm_end is aligned
dure to split or driver's mmap() ops.
Add page alignment to fix those issues.
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Bob Liu <lliubbo@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Greg Ungerer <gerg@snapgear.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The zone->lru_lock is heavily contented in workload where activate_page()
is frequently used. We could do batch activate_page() to reduce the lock
contention. The batched pages will be added into zone list when the pool
is full or page reclaim is trying to drain them.
For example, in a 4 socket 64 CPU system, create a sparse file and 64
processes, processes shared map to the file. Each process read access the
whole file and then exit. The process exit will do unmap_vmas() and cause
a lot of activate_page() call. In such workload, we saw about 58% total
time reduction with below patch. Other workloads with a lot of
activate_page also benefits a lot too.
Andrew Morton suggested activate_page() and putback_lru_pages() should
follow the same path to active pages, but this is hard to implement (see
commit 7a608572a2 ("Revert "mm: batch activate_page() to reduce lock
contention")). On the other hand, do we really need putback_lru_pages()
to follow the same path? I tested several FIO/FFSB benchmark (about 20
scripts for each benchmark) in 3 machines here from 2 sockets to 4
sockets. My test doesn't show anything significant with/without below
patch (there is slight difference but mostly some noise which we found
even without below patch before). Below patch basically returns to the
same as my first post.
I tested some microbenchmarks:
case-anon-cow-rand-mt 0.58%
case-anon-cow-rand -3.30%
case-anon-cow-seq-mt -0.51%
case-anon-cow-seq -5.68%
case-anon-r-rand-mt 0.23%
case-anon-r-rand 0.81%
case-anon-r-seq-mt -0.71%
case-anon-r-seq -1.99%
case-anon-rx-rand-mt 2.11%
case-anon-rx-seq-mt 3.46%
case-anon-w-rand-mt -0.03%
case-anon-w-rand -0.50%
case-anon-w-seq-mt -1.08%
case-anon-w-seq -0.12%
case-anon-wx-rand-mt -5.02%
case-anon-wx-seq-mt -1.43%
case-fork 1.65%
case-fork-sleep -0.07%
case-fork-withmem 1.39%
case-hugetlb -0.59%
case-lru-file-mmap-read-mt -0.54%
case-lru-file-mmap-read 0.61%
case-lru-file-mmap-read-rand -2.24%
case-lru-file-readonce -0.64%
case-lru-file-readtwice -11.69%
case-lru-memcg -1.35%
case-mmap-pread-rand-mt 1.88%
case-mmap-pread-rand -15.26%
case-mmap-pread-seq-mt 0.89%
case-mmap-pread-seq -69.72%
case-mmap-xread-rand-mt 0.71%
case-mmap-xread-seq-mt 0.38%
The most significent are:
case-lru-file-readtwice -11.69%
case-mmap-pread-rand -15.26%
case-mmap-pread-seq -69.72%
which use activate_page a lot. others are basically variations because
each run has slightly difference.
In UP case, 'size mm/swap.o'
before the two patches:
text data bss dec hex filename
6466 896 4 7366 1cc6 mm/swap.o
after the two patches:
text data bss dec hex filename
6343 896 4 7243 1c4b mm/swap.o
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Johannes Weiner <hannes@cmpxchg.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>
I believe I found a problem in __alloc_pages_slowpath, which allows a
process to get stuck endlessly looping, even when lots of memory is
available.
Running an I/O and memory intensive stress-test I see a 0-order page
allocation with __GFP_IO and __GFP_WAIT, running on a system with very
little free memory. Right about the same time that the stress-test gets
killed by the OOM-killer, the utility trying to allocate memory gets stuck
in __alloc_pages_slowpath even though most of the systems memory was freed
by the oom-kill of the stress-test.
The utility ends up looping from the rebalance label down through the
wait_iff_congested continiously. Because order=0,
__alloc_pages_direct_compact skips the call to get_page_from_freelist.
Because all of the reclaimable memory on the system has already been
reclaimed, __alloc_pages_direct_reclaim skips the call to
get_page_from_freelist. Since there is no __GFP_FS flag, the block with
__alloc_pages_may_oom is skipped. The loop hits the wait_iff_congested,
then jumps back to rebalance without ever trying to
get_page_from_freelist. This loop repeats infinitely.
The test case is pretty pathological. Running a mix of I/O stress-tests
that do a lot of fork() and consume all of the system memory, I can pretty
reliably hit this on 600 nodes, in about 12 hours. 32GB/node.
Signed-off-by: Andrew Barry <abarry@cray.com>
Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Rik van Riel<riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The noswapaccount parameter has been deprecated since 2.6.38 without any
complaints from users so we can remove it. swapaccount=0|1 can be used
instead.
As we are removing the parameter we can also clean up swapaccount because
it doesn't have to accept an empty string anymore (to match noswapaccount)
and so we can push = into __setup macro rather than checking "=1" resp.
"=0" strings
Signed-off-by: Michal Hocko <mhocko@suse.cz>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Moving show_numa_map() from mempolicy.c to task_mmu.c solves several
issues.
- Having the show() operation "miles away" from the corresponding
seq_file iteration operations is a maintenance burden.
- The need to export ad hoc info like struct proc_maps_private is
eliminated.
- The implementation of show_numa_map() can be improved in a simple
manner by cooperating with the other seq_file operations (start,
stop, etc) -- something that would be messy to do without this
change.
Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This function has been superseded by gather_hugetbl_stats() and is no
longer needed.
Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Improve the prototype of gather_stats() to take a struct numa_maps as
argument instead of a generic void *. Update all callers to make the
required type explicit.
Since gather_stats() is not needed before its definition and is scheduled
to be moved out of mempolicy.c the declaration is removed as well.
Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Mapping statistics in a NUMA environment is now computed using the generic
walk_page_range() logic. Remove the old/equivalent functionality.
Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Converting show_numa_map() to use the generic routine decouples the
function from mempolicy.c, allowing it to be moved out of the mm subsystem
and into fs/proc.
Also, include KSM pages in /proc/pid/numa_maps statistics. The pagewalk
logic implemented by check_pte_range() failed to account for such pages as
they were not applicable to the page migration case.
Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In commit 48fce3429d ("mempolicies: unexport get_vma_policy()")
get_vma_policy() was marked static as all clients were local to
mempolicy.c.
However, the decision to generate /proc/pid/numa_maps in the numa memory
policy code and outside the procfs subsystem introduces an artificial
interdependency between the two systems. Exporting get_vma_policy() once
again is the first step to clean up this interdependency.
Signed-off-by: Stephen Wilson <wilsons@start.ca>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Implement generic xattrs for tmpfs filesystems. The Feodra project, while
trying to replace suid apps with file capabilities, realized that tmpfs,
which is used on the build systems, does not support file capabilities and
thus cannot be used to build packages which use file capabilities. Xattrs
are also needed for overlayfs.
The xattr interface is a bit odd. If a filesystem does not implement any
{get,set,list}xattr functions the VFS will call into some random LSM hooks
and the running LSM can then implement some method for handling xattrs.
SELinux for example provides a method to support security.selinux but no
other security.* xattrs.
As it stands today when one enables CONFIG_TMPFS_POSIX_ACL tmpfs will have
xattr handler routines specifically to handle acls. Because of this tmpfs
would loose the VFS/LSM helpers to support the running LSM. To make up
for that tmpfs had stub functions that did nothing but call into the LSM
hooks which implement the helpers.
This new patch does not use the LSM fallback functions and instead just
implements a native get/set/list xattr feature for the full security.* and
trusted.* namespace like a normal filesystem. This means that tmpfs can
now support both security.selinux and security.capability, which was not
previously possible.
The basic implementation is that I attach a:
struct shmem_xattr {
struct list_head list; /* anchored by shmem_inode_info->xattr_list */
char *name;
size_t size;
char value[0];
};
Into the struct shmem_inode_info for each xattr that is set. This
implementation could easily support the user.* namespace as well, except
some care needs to be taken to prevent large amounts of unswappable memory
being allocated for unprivileged users.
[mszeredi@suse.cz: new config option, suport trusted.*, support symlinks]
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Tested-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Hugh Dickins <hughd@google.com>
Tested-by: Jordi Pujol <jordipujolp@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The bootmem wrapper with memblock supports top-down now, so we no longer
need this trick.
Signed-off-by: Yinghai LU <yinghai@kernel.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Olaf Hering <olaf@aepfle.de>
Cc: Tejun Heo <tj@kernel.org>
Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The page allocator will improperly return a page from ZONE_NORMAL even
when __GFP_DMA is passed if CONFIG_ZONE_DMA is disabled. The caller
expects DMA memory, perhaps for ISA devices with 16-bit address registers,
and may get higher memory resulting in undefined behavior.
This patch causes the page allocator to return NULL in such circumstances
with a warning emitted to the kernel log on the first occurrence.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.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>
online_pages() is only compiled for CONFIG_MEMORY_HOTPLUG_SPARSE, so there
is no need to support CONFIG_FLATMEM code within it.
This patch removes code that is never used.
Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
Acked-by: Dave Hansen <dave@linux.vnet.ibm.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>
It's pointless that deactive_page's operates on unevictable pages. This
patch removes unnecessary overhead which might be a bit problem in case
that there are many unevictable page in system(ex, mprotect workload)
[akpm@linux-foundation.org: tidy up comment]
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Minchan Kim <minchan.kim@gmail.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>
Previously the mmap sequential readahead is triggered by updating
ra->prev_pos on each page fault and compare it with current page offset.
It costs dirtying the cache line on each _minor_ page fault. So remove
the ra->prev_pos recording, and instead tag PG_readahead to trigger the
possible sequential readahead. It's not only more simple, but also will
work more reliably and reduce cache line bouncing on concurrent page
faults on shared struct file.
In the mosbench exim benchmark which does multi-threaded page faults on
shared struct file, the ra->mmap_miss and ra->prev_pos updates are found
to cause excessive cache line bouncing on tmpfs, which actually disabled
readahead totally (shmem_backing_dev_info.ra_pages == 0).
So remove the ra->prev_pos recording, and instead tag PG_readahead to
trigger the possible sequential readahead. It's not only more simple, but
also will work more reliably on concurrent reads on shared struct file.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Tested-by: Tim Chen <tim.c.chen@intel.com>
Reported-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The original INT_MAX is too large, reduce it to
- avoid unnecessarily dirtying/bouncing the cache line
- restore mmap read-around faster on changed access pattern
Background: in the mosbench exim benchmark which does multi-threaded page
faults on shared struct file, the ra->mmap_miss updates are found to cause
excessive cache line bouncing on tmpfs. The ra state updates are needless
for tmpfs because it actually disabled readahead totally
(shmem_backing_dev_info.ra_pages == 0).
Tested-by: Tim Chen <tim.c.chen@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reduce readahead overheads by returning early in do_sync_mmap_readahead().
tmpfs has ra_pages=0 and it can page fault really fast (not constraint by
IO if not swapping).
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Tested-by: Tim Chen <tim.c.chen@intel.com>
Reported-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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>
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>
Pass __GFP_NORETRY|__GFP_NOWARN for readahead page allocations.
readahead page allocations are completely optional. They are OK to fail
and in particular shall not trigger OOM on themselves.
Reported-by: Dave Young <hidave.darkstar@gmail.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This fixes a problem where the first pageblock got marked MIGRATE_RESERVE
even though it only had a few free pages. eg, On current ARM port, The
kernel starts at offset 0x8000 to leave room for boot parameters, and the
memory is freed later.
This in turn caused no contiguous memory to be reserved and frequent
kswapd wakeups that emptied the caches to get more contiguous memory.
Unfortunatelly, ARM needs order-2 allocation for pgd (see
arm/mm/pgd.c#pgd_alloc()). Therefore the issue is not minor nor easy
avoidable.
[kosaki.motohiro@jp.fujitsu.com: added some explanation]
[kosaki.motohiro@jp.fujitsu.com: add !pfn_valid_within() to check]
[minchan.kim@gmail.com: check end_pfn in pageblock_is_reserved]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: 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>
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>
isolate_lru_page() must be called only with stable reference to page. So,
let's grab normal page reference.
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>
Lai Jiangshan