mirror of https://gitee.com/openkylin/linux.git
70 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Michel Lespinasse
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db97141882 |
mm: adjust final #endif position in mm/internal.h
Make sure the #endif that terminates the standard #ifndef / #define / #endif construct gets labeled, and gets positioned at the end of the file as is normally the case. Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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1fb3f8ca0e |
mm: compaction: capture a suitable high-order page immediately when it is made available
While compaction is migrating pages to free up large contiguous blocks for allocation it races with other allocation requests that may steal these blocks or break them up. This patch alters direct compaction to capture a suitable free page as soon as it becomes available to reduce this race. It uses similar logic to split_free_page() to ensure that watermarks are still obeyed. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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c67fe3752a |
mm: compaction: Abort async compaction if locks are contended or taking too long
Jim Schutt reported a problem that pointed at compaction contending
heavily on locks. The workload is straight-forward and in his own words;
The systems in question have 24 SAS drives spread across 3 HBAs,
running 24 Ceph OSD instances, one per drive. FWIW these servers
are dual-socket Intel 5675 Xeons w/48 GB memory. I've got ~160
Ceph Linux clients doing dd simultaneously to a Ceph file system
backed by 12 of these servers.
Early in the test everything looks fine
procs -------------------memory------------------ ---swap-- -----io---- --system-- -----cpu-------
r b swpd free buff cache si so bi bo in cs us sy id wa st
31 15 0 287216 576 38606628 0 0 2 1158 2 14 1 3 95 0 0
27 15 0 225288 576 38583384 0 0 18 2222016 203357 134876 11 56 17 15 0
28 17 0 219256 576 38544736 0 0 11 2305932 203141 146296 11 49 23 17 0
6 18 0 215596 576 38552872 0 0 7 2363207 215264 166502 12 45 22 20 0
22 18 0 226984 576 38596404 0 0 3 2445741 223114 179527 12 43 23 22 0
and then it goes to pot
procs -------------------memory------------------ ---swap-- -----io---- --system-- -----cpu-------
r b swpd free buff cache si so bi bo in cs us sy id wa st
163 8 0 464308 576 36791368 0 0 11 22210 866 536 3 13 79 4 0
207 14 0 917752 576 36181928 0 0 712 1345376 134598 47367 7 90 1 2 0
123 12 0 685516 576 36296148 0 0 429 1386615 158494 60077 8 84 5 3 0
123 12 0 598572 576 36333728 0 0 1107 1233281 147542 62351 7 84 5 4 0
622 7 0 660768 576 36118264 0 0 557 1345548 151394 59353 7 85 4 3 0
223 11 0 283960 576 36463868 0 0 46 1107160 121846 33006 6 93 1 1 0
Note that system CPU usage is very high blocks being written out has
dropped by 42%. He analysed this with perf and found
perf record -g -a sleep 10
perf report --sort symbol --call-graph fractal,5
34.63% [k] _raw_spin_lock_irqsave
|
|--97.30%-- isolate_freepages
| compaction_alloc
| unmap_and_move
| migrate_pages
| compact_zone
| compact_zone_order
| try_to_compact_pages
| __alloc_pages_direct_compact
| __alloc_pages_slowpath
| __alloc_pages_nodemask
| alloc_pages_vma
| do_huge_pmd_anonymous_page
| handle_mm_fault
| do_page_fault
| page_fault
| |
| |--87.39%-- skb_copy_datagram_iovec
| | tcp_recvmsg
| | inet_recvmsg
| | sock_recvmsg
| | sys_recvfrom
| | system_call
| | __recv
| | |
| | --100.00%-- (nil)
| |
| --12.61%-- memcpy
--2.70%-- [...]
There was other data but primarily it is all showing that compaction is
contended heavily on the zone->lock and zone->lru_lock.
commit [b2eef8c0: mm: compaction: minimise the time IRQs are disabled
while isolating pages for migration] noted that it was possible for
migration to hold the lru_lock for an excessive amount of time. Very
broadly speaking this patch expands the concept.
This patch introduces compact_checklock_irqsave() to check if a lock
is contended or the process needs to be scheduled. If either condition
is true then async compaction is aborted and the caller is informed.
The page allocator will fail a THP allocation if compaction failed due
to contention. This patch also introduces compact_trylock_irqsave()
which will acquire the lock only if it is not contended and the process
does not need to schedule.
Reported-by: Jim Schutt <jaschut@sandia.gov>
Tested-by: Jim Schutt <jaschut@sandia.gov>
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Mel Gorman
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c93bdd0e03 |
netvm: allow skb allocation to use PFMEMALLOC reserves
Change the skb allocation API to indicate RX usage and use this to fall back to the PFMEMALLOC reserve when needed. SKBs allocated from the reserve are tagged in skb->pfmemalloc. If an SKB is allocated from the reserve and the socket is later found to be unrelated to page reclaim, the packet is dropped so that the memory remains available for page reclaim. Network protocols are expected to recover from this packet loss. [a.p.zijlstra@chello.nl: Ideas taken from various patches] [davem@davemloft.net: Use static branches, coding style corrections] [sebastian@breakpoint.cc: Avoid unnecessary cast, fix !CONFIG_NET build] Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: David S. Miller <davem@davemloft.net> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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072bb0aa5e |
mm: sl[au]b: add knowledge of PFMEMALLOC reserve pages
When a user or administrator requires swap for their application, they create a swap partition and file, format it with mkswap and activate it with swapon. Swap over the network is considered as an option in diskless systems. The two likely scenarios are when blade servers are used as part of a cluster where the form factor or maintenance costs do not allow the use of disks and thin clients. The Linux Terminal Server Project recommends the use of the Network Block Device (NBD) for swap according to the manual at https://sourceforge.net/projects/ltsp/files/Docs-Admin-Guide/LTSPManual.pdf/download There is also documentation and tutorials on how to setup swap over NBD at places like https://help.ubuntu.com/community/UbuntuLTSP/EnableNBDSWAP The nbd-client also documents the use of NBD as swap. Despite this, the fact is that a machine using NBD for swap can deadlock within minutes if swap is used intensively. This patch series addresses the problem. The core issue is that network block devices do not use mempools like normal block devices do. As the host cannot control where they receive packets from, they cannot reliably work out in advance how much memory they might need. Some years ago, Peter Zijlstra developed a series of patches that supported swap over an NFS that at least one distribution is carrying within their kernels. This patch series borrows very heavily from Peter's work to support swapping over NBD as a pre-requisite to supporting swap-over-NFS. The bulk of the complexity is concerned with preserving memory that is allocated from the PFMEMALLOC reserves for use by the network layer which is needed for both NBD and NFS. Patch 1 adds knowledge of the PFMEMALLOC reserves to SLAB and SLUB to preserve access to pages allocated under low memory situations to callers that are freeing memory. Patch 2 optimises the SLUB fast path to avoid pfmemalloc checks Patch 3 introduces __GFP_MEMALLOC to allow access to the PFMEMALLOC reserves without setting PFMEMALLOC. Patch 4 opens the possibility for softirqs to use PFMEMALLOC reserves for later use by network packet processing. Patch 5 only sets page->pfmemalloc when ALLOC_NO_WATERMARKS was required Patch 6 ignores memory policies when ALLOC_NO_WATERMARKS is set. Patches 7-12 allows network processing to use PFMEMALLOC reserves when the socket has been marked as being used by the VM to clean pages. If packets are received and stored in pages that were allocated under low-memory situations and are unrelated to the VM, the packets are dropped. Patch 11 reintroduces __skb_alloc_page which the networking folk may object to but is needed in some cases to propogate pfmemalloc from a newly allocated page to an skb. If there is a strong objection, this patch can be dropped with the impact being that swap-over-network will be slower in some cases but it should not fail. Patch 13 is a micro-optimisation to avoid a function call in the common case. Patch 14 tags NBD sockets as being SOCK_MEMALLOC so they can use PFMEMALLOC if necessary. Patch 15 notes that it is still possible for the PFMEMALLOC reserve to be depleted. To prevent this, direct reclaimers get throttled on a waitqueue if 50% of the PFMEMALLOC reserves are depleted. It is expected that kswapd and the direct reclaimers already running will clean enough pages for the low watermark to be reached and the throttled processes are woken up. Patch 16 adds a statistic to track how often processes get throttled Some basic performance testing was run using kernel builds, netperf on loopback for UDP and TCP, hackbench (pipes and sockets), iozone and sysbench. Each of them were expected to use the sl*b allocators reasonably heavily but there did not appear to be significant performance variances. For testing swap-over-NBD, a machine was booted with 2G of RAM with a swapfile backed by NBD. 8*NUM_CPU processes were started that create anonymous memory mappings and read them linearly in a loop. The total size of the mappings were 4*PHYSICAL_MEMORY to use swap heavily under memory pressure. Without the patches and using SLUB, the machine locks up within minutes and runs to completion with them applied. With SLAB, the story is different as an unpatched kernel run to completion. However, the patched kernel completed the test 45% faster. MICRO 3.5.0-rc2 3.5.0-rc2 vanilla swapnbd Unrecognised test vmscan-anon-mmap-write MMTests Statistics: duration Sys Time Running Test (seconds) 197.80 173.07 User+Sys Time Running Test (seconds) 206.96 182.03 Total Elapsed Time (seconds) 3240.70 1762.09 This patch: mm: sl[au]b: add knowledge of PFMEMALLOC reserve pages Allocations of pages below the min watermark run a risk of the machine hanging due to a lack of memory. To prevent this, only callers who have PF_MEMALLOC or TIF_MEMDIE set and are not processing an interrupt are allowed to allocate with ALLOC_NO_WATERMARKS. Once they are allocated to a slab though, nothing prevents other callers consuming free objects within those slabs. This patch limits access to slab pages that were alloced from the PFMEMALLOC reserves. When this patch is applied, pages allocated from below the low watermark are returned with page->pfmemalloc set and it is up to the caller to determine how the page should be protected. SLAB restricts access to any page with page->pfmemalloc set to callers which are known to able to access the PFMEMALLOC reserve. If one is not available, an attempt is made to allocate a new page rather than use a reserve. SLUB is a bit more relaxed in that it only records if the current per-CPU page was allocated from PFMEMALLOC reserve and uses another partial slab if the caller does not have the necessary GFP or process flags. This was found to be sufficient in tests to avoid hangs due to SLUB generally maintaining smaller lists than SLAB. In low-memory conditions it does mean that !PFMEMALLOC allocators can fail a slab allocation even though free objects are available because they are being preserved for callers that are freeing pages. [a.p.zijlstra@chello.nl: Original implementation] [sebastian@breakpoint.cc: Correct order of page flag clearing] Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: David Miller <davem@davemloft.net> Cc: Neil Brown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Christie <michaelc@cs.wisc.edu> Cc: Eric B Munson <emunson@mgebm.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Sebastian Andrzej Siewior <sebastian@breakpoint.cc> Cc: Mel Gorman <mgorman@suse.de> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Xishi Qiu
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ca57df79d4 |
mm: setup pageblock_order before it's used by sparsemem
On architectures with CONFIG_HUGETLB_PAGE_SIZE_VARIABLE set, such as
Itanium, pageblock_order is a variable with default value of 0. It's set
to the right value by set_pageblock_order() in function
free_area_init_core().
But pageblock_order may be used by sparse_init() before free_area_init_core()
is called along path:
sparse_init()
->sparse_early_usemaps_alloc_node()
->usemap_size()
->SECTION_BLOCKFLAGS_BITS
->((1UL << (PFN_SECTION_SHIFT - pageblock_order)) *
NR_PAGEBLOCK_BITS)
The uninitialized pageblock_size will cause memory wasting because
usemap_size() returns a much bigger value then it's really needed.
For example, on an Itanium platform,
sparse_init() pageblock_order=0 usemap_size=24576
free_area_init_core() before pageblock_order=0, usemap_size=24576
free_area_init_core() after pageblock_order=12, usemap_size=8
That means 24K memory has been wasted for each section, so fix it by calling
set_pageblock_order() from sparse_init().
Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
Signed-off-by: Jiang Liu <liuj97@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Keping Chen <chenkeping@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Rik van Riel
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7db8889ab0 |
mm: have order > 0 compaction start off where it left
Order > 0 compaction stops when enough free pages of the correct page order have been coalesced. When doing subsequent higher order allocations, it is possible for compaction to be invoked many times. However, the compaction code always starts out looking for things to compact at the start of the zone, and for free pages to compact things to at the end of the zone. This can cause quadratic behaviour, with isolate_freepages starting at the end of the zone each time, even though previous invocations of the compaction code already filled up all free memory on that end of the zone. This can cause isolate_freepages to take enormous amounts of CPU with certain workloads on larger memory systems. The obvious solution is to have isolate_freepages remember where it left off last time, and continue at that point the next time it gets invoked for an order > 0 compaction. This could cause compaction to fail if cc->free_pfn and cc->migrate_pfn are close together initially, in that case we restart from the end of the zone and try once more. Forced full (order == -1) compactions are left alone. [akpm@linux-foundation.org: checkpatch fixes] [akpm@linux-foundation.org: s/laste/last/, use 80 cols] Signed-off-by: Rik van Riel <riel@redhat.com> Reported-by: Jim Schutt <jaschut@sandia.gov> Tested-by: Jim Schutt <jaschut@sandia.gov> Cc: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Linus Torvalds
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68e3e92620 |
Revert "mm: compaction: handle incorrect MIGRATE_UNMOVABLE type pageblocks"
This reverts commit
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Linus Torvalds
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1193755ac6 |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs changes from Al Viro.
"A lot of misc stuff. The obvious groups:
* Miklos' atomic_open series; kills the damn abuse of
->d_revalidate() by NFS, which was the major stumbling block for
all work in that area.
* ripping security_file_mmap() and dealing with deadlocks in the
area; sanitizing the neighborhood of vm_mmap()/vm_munmap() in
general.
* ->encode_fh() switched to saner API; insane fake dentry in
mm/cleancache.c gone.
* assorted annotations in fs (endianness, __user)
* parts of Artem's ->s_dirty work (jff2 and reiserfs parts)
* ->update_time() work from Josef.
* other bits and pieces all over the place.
Normally it would've been in two or three pull requests, but
signal.git stuff had eaten a lot of time during this cycle ;-/"
Fix up trivial conflicts in Documentation/filesystems/vfs.txt (the
'truncate_range' inode method was removed by the VM changes, the VFS
update adds an 'update_time()' method), and in fs/btrfs/ulist.[ch] (due
to sparse fix added twice, with other changes nearby).
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (95 commits)
nfs: don't open in ->d_revalidate
vfs: retry last component if opening stale dentry
vfs: nameidata_to_filp(): don't throw away file on error
vfs: nameidata_to_filp(): inline __dentry_open()
vfs: do_dentry_open(): don't put filp
vfs: split __dentry_open()
vfs: do_last() common post lookup
vfs: do_last(): add audit_inode before open
vfs: do_last(): only return EISDIR for O_CREAT
vfs: do_last(): check LOOKUP_DIRECTORY
vfs: do_last(): make ENOENT exit RCU safe
vfs: make follow_link check RCU safe
vfs: do_last(): use inode variable
vfs: do_last(): inline walk_component()
vfs: do_last(): make exit RCU safe
vfs: split do_lookup()
Btrfs: move over to use ->update_time
fs: introduce inode operation ->update_time
reiserfs: get rid of resierfs_sync_super
reiserfs: mark the superblock as dirty a bit later
...
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Al Viro
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eb36c5873b |
new helper: vm_mmap_pgoff()
take it to mm/util.c, convert vm_mmap() to use of that one and take it to mm/util.c as well, convert both sys_mmap_pgoff() to use of vm_mmap_pgoff() Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> |
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Bartlomiej Zolnierkiewicz
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5ceb9ce6fe |
mm: compaction: handle incorrect MIGRATE_UNMOVABLE type pageblocks
When MIGRATE_UNMOVABLE pages are freed from MIGRATE_UNMOVABLE type pageblock (and some MIGRATE_MOVABLE pages are left in it) waiting until an allocation takes ownership of the block may take too long. The type of the pageblock remains unchanged so the pageblock cannot be used as a migration target during compaction. Fix it by: * Adding enum compact_mode (COMPACT_ASYNC_[MOVABLE,UNMOVABLE], and COMPACT_SYNC) and then converting sync field in struct compact_control to use it. * Adding nr_pageblocks_skipped field to struct compact_control and tracking how many destination pageblocks were of MIGRATE_UNMOVABLE type. If COMPACT_ASYNC_MOVABLE mode compaction ran fully in try_to_compact_pages() (COMPACT_COMPLETE) it implies that there is not a suitable page for allocation. In this case then check how if there were enough MIGRATE_UNMOVABLE pageblocks to try a second pass in COMPACT_ASYNC_UNMOVABLE mode. * Scanning the MIGRATE_UNMOVABLE pageblocks (during COMPACT_SYNC and COMPACT_ASYNC_UNMOVABLE compaction modes) and building a count based on finding PageBuddy pages, page_count(page) == 0 or PageLRU pages. If all pages within the MIGRATE_UNMOVABLE pageblock are in one of those three sets change the whole pageblock type to MIGRATE_MOVABLE. My particular test case (on a ARM EXYNOS4 device with 512 MiB, which means 131072 standard 4KiB pages in 'Normal' zone) is to: - allocate 120000 pages for kernel's usage - free every second page (60000 pages) of memory just allocated - allocate and use 60000 pages from user space - free remaining 60000 pages of kernel memory (now we have fragmented memory occupied mostly by user space pages) - try to allocate 100 order-9 (2048 KiB) pages for kernel's usage The results: - with compaction disabled I get 11 successful allocations - with compaction enabled - 14 successful allocations - with this patch I'm able to get all 100 successful allocations NOTE: If we can make kswapd aware of order-0 request during compaction, we can enhance kswapd with changing mode to COMPACT_ASYNC_FULL (COMPACT_ASYNC_MOVABLE + COMPACT_ASYNC_UNMOVABLE). Please see the following thread: http://marc.info/?l=linux-mm&m=133552069417068&w=2 [minchan@kernel.org: minor cleanups] Cc: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Ying Han
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096a7cf447 |
mm: rename is_mlocked_vma() to mlocked_vma_newpage()
Andrew pointed out that the is_mlocked_vma() is misnamed. A function with name like that would expect bool return and no side-effects. Since it is called on the fault path for new page, rename it in this patch. Signed-off-by: Ying Han <yinghan@google.com> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujtisu.com> Reviewed-by: Minchan Kim <minchan@kernel.org> [akpm@linux-foundation.org: s/mlock_vma_newpage/mlock_vma_newpage/, per Minchan] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Michal Nazarewicz
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ff9543fd32 |
mm: compaction: export some of the functions
This commit exports some of the functions from compaction.c file outside of it adding their declaration into internal.h header file so that other mm related code can use them. This forced compaction.c to always be compiled (as opposed to being compiled only if CONFIG_COMPACTION is defined) but as to avoid introducing code that user did not ask for, part of the compaction.c is now wrapped in on #ifdef. Signed-off-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Tested-by: Rob Clark <rob.clark@linaro.org> Tested-by: Ohad Ben-Cohen <ohad@wizery.com> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org> Tested-by: Robert Nelson <robertcnelson@gmail.com> Tested-by: Barry Song <Baohua.Song@csr.com> |
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Andrea Arcangeli
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70b50f94f1 |
mm: thp: tail page refcounting fix
Michel while working on the working set estimation code, noticed that calling get_page_unless_zero() on a random pfn_to_page(random_pfn) wasn't safe, if the pfn ended up being a tail page of a transparent hugepage under splitting by __split_huge_page_refcount(). He then found the problem could also theoretically materialize with page_cache_get_speculative() during the speculative radix tree lookups that uses get_page_unless_zero() in SMP if the radix tree page is freed and reallocated and get_user_pages is called on it before page_cache_get_speculative has a chance to call get_page_unless_zero(). So the best way to fix the problem is to keep page_tail->_count zero at all times. This will guarantee that get_page_unless_zero() can never succeed on any tail page. page_tail->_mapcount is guaranteed zero and is unused for all tail pages of a compound page, so we can simply account the tail page references there and transfer them to tail_page->_count in __split_huge_page_refcount() (in addition to the head_page->_mapcount). While debugging this s/_count/_mapcount/ change I also noticed get_page is called by direct-io.c on pages returned by get_user_pages. That wasn't entirely safe because the two atomic_inc in get_page weren't atomic. As opposed to other get_user_page users like secondary-MMU page fault to establish the shadow pagetables would never call any superflous get_page after get_user_page returns. It's safer to make get_page universally safe for tail pages and to use get_page_foll() within follow_page (inside get_user_pages()). get_page_foll() is safe to do the refcounting for tail pages without taking any locks because it is run within PT lock protected critical sections (PT lock for pte and page_table_lock for pmd_trans_huge). The standard get_page() as invoked by direct-io instead will now take the compound_lock but still only for tail pages. The direct-io paths are usually I/O bound and the compound_lock is per THP so very finegrined, so there's no risk of scalability issues with it. A simple direct-io benchmarks with all lockdep prove locking and spinlock debugging infrastructure enabled shows identical performance and no overhead. So it's worth it. Ideally direct-io should stop calling get_page() on pages returned by get_user_pages(). The spinlock in get_page() is already optimized away for no-THP builds but doing get_page() on tail pages returned by GUP is generally a rare operation and usually only run in I/O paths. This new refcounting on page_tail->_mapcount in addition to avoiding new RCU critical sections will also allow the working set estimation code to work without any further complexity associated to the tail page refcounting with THP. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Michel Lespinasse <walken@google.com> Reviewed-by: Michel Lespinasse <walken@google.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <jweiner@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Gibson <david@gibson.dropbear.id.au> Cc: <stable@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Namhyung Kim
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6038def0d1 |
mm: nommu: sort mm->mmap list properly
When I was reading nommu code, I found that it handles the vma list/tree
in an unusual way. IIUC, because there can be more than one
identical/overrapped vmas in the list/tree, it sorts the tree more
strictly and does a linear search on the tree. But it doesn't applied to
the list (i.e. the list could be constructed in a different order than
the tree so that we can't use the list when finding the first vma in that
order).
Since inserting/sorting a vma in the tree and link is done at the same
time, we can easily construct both of them in the same order. And linear
searching on the tree could be more costly than doing it on the list, it
can be converted to use the list.
Also, after the commit
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Lucas De Marchi
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25985edced |
Fix common misspellings
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi> |
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Huang Ying
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0014bd990e |
mm: export __get_user_pages
In most cases, get_user_pages and get_user_pages_fast should be used to pin user pages in memory. But sometimes, some special flags except FOLL_GET, FOLL_WRITE and FOLL_FORCE are needed, for example in following patch, KVM needs FOLL_HWPOISON. To support these users, __get_user_pages is exported directly. There are some symbol name conflicts in infiniband driver, fixed them too. Signed-off-by: Huang Ying <ying.huang@intel.com> CC: Andrew Morton <akpm@linux-foundation.org> CC: Michel Lespinasse <walken@google.com> CC: Roland Dreier <roland@kernel.org> CC: Ralph Campbell <infinipath@qlogic.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> |
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Linus Torvalds
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7a608572a2 |
Revert "mm: batch activate_page() to reduce lock contention"
This reverts commit |
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Shaohua Li
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744ed14427 |
mm: batch activate_page() to reduce lock contention
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. 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. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Shaohua Li <shaohua.li@intel.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@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> |
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Andrea Arcangeli
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71e3aac072 |
thp: transparent hugepage core
Lately I've been working to make KVM use hugepages transparently without
the usual restrictions of hugetlbfs. Some of the restrictions I'd like to
see removed:
1) hugepages have to be swappable or the guest physical memory remains
locked in RAM and can't be paged out to swap
2) if a hugepage allocation fails, regular pages should be allocated
instead and mixed in the same vma without any failure and without
userland noticing
3) if some task quits and more hugepages become available in the
buddy, guest physical memory backed by regular pages should be
relocated on hugepages automatically in regions under
madvise(MADV_HUGEPAGE) (ideally event driven by waking up the
kernel deamon if the order=HPAGE_PMD_SHIFT-PAGE_SHIFT list becomes
not null)
4) avoidance of reservation and maximization of use of hugepages whenever
possible. Reservation (needed to avoid runtime fatal faliures) may be ok for
1 machine with 1 database with 1 database cache with 1 database cache size
known at boot time. It's definitely not feasible with a virtualization
hypervisor usage like RHEV-H that runs an unknown number of virtual machines
with an unknown size of each virtual machine with an unknown amount of
pagecache that could be potentially useful in the host for guest not using
O_DIRECT (aka cache=off).
hugepages in the virtualization hypervisor (and also in the guest!) are
much more important than in a regular host not using virtualization,
becasue with NPT/EPT they decrease the tlb-miss cacheline accesses from 24
to 19 in case only the hypervisor uses transparent hugepages, and they
decrease the tlb-miss cacheline accesses from 19 to 15 in case both the
linux hypervisor and the linux guest both uses this patch (though the
guest will limit the addition speedup to anonymous regions only for
now...). Even more important is that the tlb miss handler is much slower
on a NPT/EPT guest than for a regular shadow paging or no-virtualization
scenario. So maximizing the amount of virtual memory cached by the TLB
pays off significantly more with NPT/EPT than without (even if there would
be no significant speedup in the tlb-miss runtime).
The first (and more tedious) part of this work requires allowing the VM to
handle anonymous hugepages mixed with regular pages transparently on
regular anonymous vmas. This is what this patch tries to achieve in the
least intrusive possible way. We want hugepages and hugetlb to be used in
a way so that all applications can benefit without changes (as usual we
leverage the KVM virtualization design: by improving the Linux VM at
large, KVM gets the performance boost too).
The most important design choice is: always fallback to 4k allocation if
the hugepage allocation fails! This is the _very_ opposite of some large
pagecache patches that failed with -EIO back then if a 64k (or similar)
allocation failed...
Second important decision (to reduce the impact of the feature on the
existing pagetable handling code) is that at any time we can split an
hugepage into 512 regular pages and it has to be done with an operation
that can't fail. This way the reliability of the swapping isn't decreased
(no need to allocate memory when we are short on memory to swap) and it's
trivial to plug a split_huge_page* one-liner where needed without
polluting the VM. Over time we can teach mprotect, mremap and friends to
handle pmd_trans_huge natively without calling split_huge_page*. The fact
it can't fail isn't just for swap: if split_huge_page would return -ENOMEM
(instead of the current void) we'd need to rollback the mprotect from the
middle of it (ideally including undoing the split_vma) which would be a
big change and in the very wrong direction (it'd likely be simpler not to
call split_huge_page at all and to teach mprotect and friends to handle
hugepages instead of rolling them back from the middle). In short the
very value of split_huge_page is that it can't fail.
The collapsing and madvise(MADV_HUGEPAGE) part will remain separated and
incremental and it'll just be an "harmless" addition later if this initial
part is agreed upon. It also should be noted that locking-wise replacing
regular pages with hugepages is going to be very easy if compared to what
I'm doing below in split_huge_page, as it will only happen when
page_count(page) matches page_mapcount(page) if we can take the PG_lock
and mmap_sem in write mode. collapse_huge_page will be a "best effort"
that (unlike split_huge_page) can fail at the minimal sign of trouble and
we can try again later. collapse_huge_page will be similar to how KSM
works and the madvise(MADV_HUGEPAGE) will work similar to
madvise(MADV_MERGEABLE).
The default I like is that transparent hugepages are used at page fault
time. This can be changed with
/sys/kernel/mm/transparent_hugepage/enabled. The control knob can be set
to three values "always", "madvise", "never" which mean respectively that
hugepages are always used, or only inside madvise(MADV_HUGEPAGE) regions,
or never used. /sys/kernel/mm/transparent_hugepage/defrag instead
controls if the hugepage allocation should defrag memory aggressively
"always", only inside "madvise" regions, or "never".
The pmd_trans_splitting/pmd_trans_huge locking is very solid. The
put_page (from get_user_page users that can't use mmu notifier like
O_DIRECT) that runs against a __split_huge_page_refcount instead was a
pain to serialize in a way that would result always in a coherent page
count for both tail and head. I think my locking solution with a
compound_lock taken only after the page_first is valid and is still a
PageHead should be safe but it surely needs review from SMP race point of
view. In short there is no current existing way to serialize the O_DIRECT
final put_page against split_huge_page_refcount so I had to invent a new
one (O_DIRECT loses knowledge on the mapping status by the time gup_fast
returns so...). And I didn't want to impact all gup/gup_fast users for
now, maybe if we change the gup interface substantially we can avoid this
locking, I admit I didn't think too much about it because changing the gup
unpinning interface would be invasive.
If we ignored O_DIRECT we could stick to the existing compound refcounting
code, by simply adding a get_user_pages_fast_flags(foll_flags) where KVM
(and any other mmu notifier user) would call it without FOLL_GET (and if
FOLL_GET isn't set we'd just BUG_ON if nobody registered itself in the
current task mmu notifier list yet). But O_DIRECT is fundamental for
decent performance of virtualized I/O on fast storage so we can't avoid it
to solve the race of put_page against split_huge_page_refcount to achieve
a complete hugepage feature for KVM.
Swap and oom works fine (well just like with regular pages ;). MMU
notifier is handled transparently too, with the exception of the young bit
on the pmd, that didn't have a range check but I think KVM will be fine
because the whole point of hugepages is that EPT/NPT will also use a huge
pmd when they notice gup returns pages with PageCompound set, so they
won't care of a range and there's just the pmd young bit to check in that
case.
NOTE: in some cases if the L2 cache is small, this may slowdown and waste
memory during COWs because 4M of memory are accessed in a single fault
instead of 8k (the payoff is that after COW the program can run faster).
So we might want to switch the copy_huge_page (and clear_huge_page too) to
not temporal stores. I also extensively researched ways to avoid this
cache trashing with a full prefault logic that would cow in 8k/16k/32k/64k
up to 1M (I can send those patches that fully implemented prefault) but I
concluded they're not worth it and they add an huge additional complexity
and they remove all tlb benefits until the full hugepage has been faulted
in, to save a little bit of memory and some cache during app startup, but
they still don't improve substantially the cache-trashing during startup
if the prefault happens in >4k chunks. One reason is that those 4k pte
entries copied are still mapped on a perfectly cache-colored hugepage, so
the trashing is the worst one can generate in those copies (cow of 4k page
copies aren't so well colored so they trashes less, but again this results
in software running faster after the page fault). Those prefault patches
allowed things like a pte where post-cow pages were local 4k regular anon
pages and the not-yet-cowed pte entries were pointing in the middle of
some hugepage mapped read-only. If it doesn't payoff substantially with
todays hardware it will payoff even less in the future with larger l2
caches, and the prefault logic would blot the VM a lot. If one is
emebdded transparent_hugepage can be disabled during boot with sysfs or
with the boot commandline parameter transparent_hugepage=0 (or
transparent_hugepage=2 to restrict hugepages inside madvise regions) that
will ensure not a single hugepage is allocated at boot time. It is simple
enough to just disable transparent hugepage globally and let transparent
hugepages be allocated selectively by applications in the MADV_HUGEPAGE
region (both at page fault time, and if enabled with the
collapse_huge_page too through the kernel daemon).
This patch supports only hugepages mapped in the pmd, archs that have
smaller hugepages will not fit in this patch alone. Also some archs like
power have certain tlb limits that prevents mixing different page size in
the same regions so they will not fit in this framework that requires
"graceful fallback" to basic PAGE_SIZE in case of physical memory
fragmentation. hugetlbfs remains a perfect fit for those because its
software limits happen to match the hardware limits. hugetlbfs also
remains a perfect fit for hugepage sizes like 1GByte that cannot be hoped
to be found not fragmented after a certain system uptime and that would be
very expensive to defragment with relocation, so requiring reservation.
hugetlbfs is the "reservation way", the point of transparent hugepages is
not to have any reservation at all and maximizing the use of cache and
hugepages at all times automatically.
Some performance result:
vmx andrea # LD_PRELOAD=/usr/lib64/libhugetlbfs.so HUGETLB_MORECORE=yes HUGETLB_PATH=/mnt/huge/ ./largep
ages3
memset page fault 1566023
memset tlb miss 453854
memset second tlb miss 453321
random access tlb miss 41635
random access second tlb miss 41658
vmx andrea # LD_PRELOAD=/usr/lib64/libhugetlbfs.so HUGETLB_MORECORE=yes HUGETLB_PATH=/mnt/huge/ ./largepages3
memset page fault 1566471
memset tlb miss 453375
memset second tlb miss 453320
random access tlb miss 41636
random access second tlb miss 41637
vmx andrea # ./largepages3
memset page fault 1566642
memset tlb miss 453417
memset second tlb miss 453313
random access tlb miss 41630
random access second tlb miss 41647
vmx andrea # ./largepages3
memset page fault 1566872
memset tlb miss 453418
memset second tlb miss 453315
random access tlb miss 41618
random access second tlb miss 41659
vmx andrea # echo 0 > /proc/sys/vm/transparent_hugepage
vmx andrea # ./largepages3
memset page fault 2182476
memset tlb miss 460305
memset second tlb miss 460179
random access tlb miss 44483
random access second tlb miss 44186
vmx andrea # ./largepages3
memset page fault 2182791
memset tlb miss 460742
memset second tlb miss 459962
random access tlb miss 43981
random access second tlb miss 43988
============
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/time.h>
#define SIZE (3UL*1024*1024*1024)
int main()
{
char *p = malloc(SIZE), *p2;
struct timeval before, after;
gettimeofday(&before, NULL);
memset(p, 0, SIZE);
gettimeofday(&after, NULL);
printf("memset page fault %Lu\n",
(after.tv_sec-before.tv_sec)*1000000UL +
after.tv_usec-before.tv_usec);
gettimeofday(&before, NULL);
memset(p, 0, SIZE);
gettimeofday(&after, NULL);
printf("memset tlb miss %Lu\n",
(after.tv_sec-before.tv_sec)*1000000UL +
after.tv_usec-before.tv_usec);
gettimeofday(&before, NULL);
memset(p, 0, SIZE);
gettimeofday(&after, NULL);
printf("memset second tlb miss %Lu\n",
(after.tv_sec-before.tv_sec)*1000000UL +
after.tv_usec-before.tv_usec);
gettimeofday(&before, NULL);
for (p2 = p; p2 < p+SIZE; p2 += 4096)
*p2 = 0;
gettimeofday(&after, NULL);
printf("random access tlb miss %Lu\n",
(after.tv_sec-before.tv_sec)*1000000UL +
after.tv_usec-before.tv_usec);
gettimeofday(&before, NULL);
for (p2 = p; p2 < p+SIZE; p2 += 4096)
*p2 = 0;
gettimeofday(&after, NULL);
printf("random access second tlb miss %Lu\n",
(after.tv_sec-before.tv_sec)*1000000UL +
after.tv_usec-before.tv_usec);
return 0;
}
============
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Michel Lespinasse
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53a7706d5e |
mlock: do not hold mmap_sem for extended periods of time
__get_user_pages gets a new 'nonblocking' parameter to signal that the caller is prepared to re-acquire mmap_sem and retry the operation if needed. This is used to split off long operations if they are going to block on a disk transfer, or when we detect contention on the mmap_sem. [akpm@linux-foundation.org: remove ref to rwsem_is_contended()] Signed-off-by: Michel Lespinasse <walken@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Nick Piggin <npiggin@kernel.dk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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KAMEZAWA Hiroyuki
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572438f9b5 |
mm: fix is_mem_section_removable() page_order BUG_ON check
page_order() is called by memory hotplug's user interface to check the section is removable or not. (is_mem_section_removable()) It calls page_order() withoug holding zone->lock. So, even if the caller does if (PageBuddy(page)) ret = page_order(page) ... The caller may hit BUG_ON(). For fixing this, there are 2 choices. 1. add zone->lock. 2. remove BUG_ON(). is_mem_section_removable() is used for some "advice" and doesn't need to be 100% accurate. This is_removable() can be called via user program.. We don't want to take this important lock for long by user's request. So, this patch removes BUG_ON(). Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Acked-by: Michal Hocko <mhocko@suse.cz> 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> |
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Haicheng Li
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1bfe5febe3 |
HWPOISON: add an interface to switch off/on all the page filters
In some use cases, user doesn't need extra filtering. E.g. user program can inject errors through madvise syscall to its own pages, however it might not know what the page state exactly is or which inode the page belongs to. So introduce an one-off interface "corrupt-filter-enable". Echo 0 to switch off page filters, and echo 1 to switch on the filters. [AK: changed default to 0] Signed-off-by: Haicheng Li <haicheng.li@linux.intel.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> |
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Andi Kleen
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4fd466eb46 |
HWPOISON: add memory cgroup filter
The hwpoison test suite need to inject hwpoison to a collection of selected task pages, and must not touch pages not owned by them and thus kill important system processes such as init. (But it's OK to mis-hwpoison free/unowned pages as well as shared clean pages. Mis-hwpoison of shared dirty pages will kill all tasks, so the test suite will target all or non of such tasks in the first place.) The memory cgroup serves this purpose well. We can put the target processes under the control of a memory cgroup, and tell the hwpoison injection code to only kill pages associated with some active memory cgroup. The prerequisite for doing hwpoison stress tests with mem_cgroup is, the mem_cgroup code tracks task pages _accurately_ (unless page is locked). Which we believe is/should be true. The benefits are simplification of hwpoison injector code. Also the mem_cgroup code will automatically be tested by hwpoison test cases. The alternative interfaces pin-pfn/unpin-pfn can also delegate the (process and page flags) filtering functions reliably to user space. However prototype implementation shows that this scheme adds more complexity than we wanted. Example test case: mkdir /cgroup/hwpoison usemem -m 100 -s 1000 & echo `jobs -p` > /cgroup/hwpoison/tasks memcg_ino=$(ls -id /cgroup/hwpoison | cut -f1 -d' ') echo $memcg_ino > /debug/hwpoison/corrupt-filter-memcg page-types -p `pidof init` --hwpoison # shall do nothing page-types -p `pidof usemem` --hwpoison # poison its pages [AK: Fix documentation] [Add fix for problem noticed by Li Zefan <lizf@cn.fujitsu.com>; dentry in the css could be NULL] CC: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> CC: Hugh Dickins <hugh.dickins@tiscali.co.uk> 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: Li Zefan <lizf@cn.fujitsu.com> CC: Paul Menage <menage@google.com> CC: Nick Piggin <npiggin@suse.de> CC: Andi Kleen <andi@firstfloor.org> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> |
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Wu Fengguang
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478c5ffc0b |
HWPOISON: add page flags filter
When specified, only poison pages if ((page_flags & mask) == value). - corrupt-filter-flags-mask - corrupt-filter-flags-value This allows stress testing of many kinds of pages. Strictly speaking, the buddy pages requires taking zone lock, to avoid setting PG_hwpoison on a "was buddy but now allocated to someone" page. However we can just do nothing because we set PG_locked in the beginning, this prevents the page allocator from allocating it to someone. (It will BUG() on the unexpected PG_locked, which is fine for hwpoison testing.) [AK: Add select PROC_PAGE_MONITOR to satisfy dependency] CC: Nick Piggin <npiggin@suse.de> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> |
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Wu Fengguang
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31d3d3484f |
HWPOISON: limit hwpoison injector to known page types
__memory_failure()'s workflow is set PG_hwpoison //... unset PG_hwpoison if didn't pass hwpoison filter That could kill unrelated process if it happens to page fault on the page with the (temporary) PG_hwpoison. The race should be big enough to appear in stress tests. Fix it by grabbing the page and checking filter at inject time. This also avoids the very noisy "Injecting memory failure..." messages. - we don't touch madvise() based injection, because the filters are generally not necessary for it. - if we want to apply the filters to h/w aided injection, we'd better to rearrange the logic in __memory_failure() instead of this patch. AK: fix documentation, use drain all, cleanups CC: Haicheng Li <haicheng.li@intel.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> |
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Wu Fengguang
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7c116f2b0d |
HWPOISON: add fs/device filters
Filesystem data/metadata present the most tricky-to-isolate pages.
It requires careful code review and stress testing to get them right.
The fs/device filter helps to target the stress tests to some specific
filesystem pages. The filter condition is block device's major/minor
numbers:
- corrupt-filter-dev-major
- corrupt-filter-dev-minor
When specified (non -1), only page cache pages that belong to that
device will be poisoned.
The filters are checked reliably on the locked and refcounted page.
Haicheng: clear PG_hwpoison and drop bad page count if filter not OK
AK: Add documentation
CC: Haicheng Li <haicheng.li@intel.com>
CC: Nick Piggin <npiggin@suse.de>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
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Wu Fengguang
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8d22ba1b74 |
HWPOISON: detect free buddy pages explicitly
Most free pages in the buddy system have no PG_buddy set. Introduce is_free_buddy_page() for detecting them reliably. CC: Nick Piggin <npiggin@suse.de> CC: Mel Gorman <mel@linux.vnet.ibm.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> |
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Lee Schermerhorn
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418b27ef50 |
mm: remove unevictable_migrate_page function
unevictable_migrate_page() in mm/internal.h is a relic of the since removed UNEVICTABLE_LRU Kconfig option. This patch removes the function and open codes the test in migrate_page_copy(). Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
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73848b4684 |
ksm: fix mlockfreed to munlocked
When KSM merges an mlocked page, it has been forgetting to munlock it: that's been left to free_page_mlock(), which reports it in /proc/vmstat as unevictable_pgs_mlockfreed instead of unevictable_pgs_munlocked (and whinges "Page flag mlocked set for process" in mmotm, whereas mainline is silently forgiving). Call munlock_vma_page() to fix that. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Izik Eidus <ieidus@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Chris Wright <chrisw@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
|
af8e3354b4 |
mm: CONFIG_MMU for PG_mlocked
Remove three degrees of obfuscation, left over from when we had CONFIG_UNEVICTABLE_LRU. MLOCK_PAGES is CONFIG_HAVE_MLOCKED_PAGE_BIT is CONFIG_HAVE_MLOCK is CONFIG_MMU. rmap.o (and memory-failure.o) are only built when CONFIG_MMU, so don't need such conditions at all. Somehow, I feel no compulsion to remove the CONFIG_HAVE_MLOCK* lines from 169 defconfigs: leave those to evolve in due course. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Izik Eidus <ieidus@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Nick Piggin <npiggin@suse.de> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Wu Fengguang <fengguang.wu@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> |
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Hugh Dickins
|
03f6462a3a |
mm: move highest_memmap_pfn
Move highest_memmap_pfn __read_mostly from page_alloc.c next to zero_pfn __read_mostly in memory.c: to help them share a cacheline, since they're very often tested together in vm_normal_page(). Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
|
58fa879e1e |
mm: FOLL flags for GUP flags
__get_user_pages() has been taking its own GUP flags, then processing them into FOLL flags for follow_page(). Though oddly named, the FOLL flags are more widely used, so pass them to __get_user_pages() now. Sorry, VM flags, VM_FAULT flags and FAULT_FLAGs are still distinct. (The patch to __get_user_pages() looks peculiar, with both gup_flags and foll_flags: the gup_flags remain constant; but as before there's an exceptional case, out of scope of the patch, in which foll_flags per page have FOLL_WRITE masked off.) Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
|
8e4b9a6071 |
mm: FOLL_DUMP replace FOLL_ANON
The "FOLL_ANON optimization" and its use_zero_page() test have caused confusion and bugs: why does it test VM_SHARED? for the very good but unsatisfying reason that VMware crashed without. As we look to maybe reinstating anonymous use of the ZERO_PAGE, we need to sort this out. Easily done: it's silly for __get_user_pages() and follow_page() to be guessing whether it's safe to assume that they're being used for a coredump (which can take a shortcut snapshot where other uses must handle a fault) - just tell them with GUP_FLAGS_DUMP and FOLL_DUMP. get_dump_page() doesn't even want a ZERO_PAGE: an error suits fine. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Hugh Dickins
|
1c3aff1cee |
mm: remove unused GUP flags
GUP_FLAGS_IGNORE_VMA_PERMISSIONS and GUP_FLAGS_IGNORE_SIGKILL were flags added solely to prevent __get_user_pages() from doing some of what it usually does, in the munlock case: we can now remove them. Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk> Acked-by: Rik van Riel <riel@redhat.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
|
fa5e084e43 |
vmscan: do not unconditionally treat zones that fail zone_reclaim() as full
On NUMA machines, the administrator can configure zone_reclaim_mode that
is a more targetted form of direct reclaim. On machines with large NUMA
distances for example, a zone_reclaim_mode defaults to 1 meaning that
clean unmapped pages will be reclaimed if the zone watermarks are not
being met. The problem is that zone_reclaim() failing at all means the
zone gets marked full.
This can cause situations where a zone is usable, but is being skipped
because it has been considered full. Take a situation where a large tmpfs
mount is occuping a large percentage of memory overall. The pages do not
get cleaned or reclaimed by zone_reclaim(), but the zone gets marked full
and the zonelist cache considers them not worth trying in the future.
This patch makes zone_reclaim() return more fine-grained information about
what occured when zone_reclaim() failued. The zone only gets marked full
if it really is unreclaimable. If it's a case that the scan did not occur
or if enough pages were not reclaimed with the limited reclaim_mode, then
the zone is simply skipped.
There is a side-effect to this patch. Currently, if zone_reclaim()
successfully reclaimed SWAP_CLUSTER_MAX, an allocation attempt would go
ahead. With this patch applied, zone watermarks are rechecked after
zone_reclaim() does some work.
This bug was introduced by commit
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KOSAKI Motohiro
|
6837765963 |
mm: remove CONFIG_UNEVICTABLE_LRU config option
Currently, nobody wants to turn UNEVICTABLE_LRU off. Thus this configurability is unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Andi Kleen <andi@firstfloor.org> Acked-by: Minchan Kim <minchan.kim@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Rik van Riel <riel@redhat.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Wu Fengguang
|
20a0307c03 |
mm: introduce PageHuge() for testing huge/gigantic pages
A series of patches to enhance the /proc/pagemap interface and to add a
userspace executable which can be used to present the pagemap data.
Export 10 more flags to end users (and more for kernel developers):
11. KPF_MMAP (pseudo flag) memory mapped page
12. KPF_ANON (pseudo flag) memory mapped page (anonymous)
13. KPF_SWAPCACHE page is in swap cache
14. KPF_SWAPBACKED page is swap/RAM backed
15. KPF_COMPOUND_HEAD (*)
16. KPF_COMPOUND_TAIL (*)
17. KPF_HUGE hugeTLB pages
18. KPF_UNEVICTABLE page is in the unevictable LRU list
19. KPF_HWPOISON hardware detected corruption
20. KPF_NOPAGE (pseudo flag) no page frame at the address
(*) For compound pages, exporting _both_ head/tail info enables
users to tell where a compound page starts/ends, and its order.
a simple demo of the page-types tool
# ./page-types -h
page-types [options]
-r|--raw Raw mode, for kernel developers
-a|--addr addr-spec Walk a range of pages
-b|--bits bits-spec Walk pages with specified bits
-l|--list Show page details in ranges
-L|--list-each Show page details one by one
-N|--no-summary Don't show summay info
-h|--help Show this usage message
addr-spec:
N one page at offset N (unit: pages)
N+M pages range from N to N+M-1
N,M pages range from N to M-1
N, pages range from N to end
,M pages range from 0 to M
bits-spec:
bit1,bit2 (flags & (bit1|bit2)) != 0
bit1,bit2=bit1 (flags & (bit1|bit2)) == bit1
bit1,~bit2 (flags & (bit1|bit2)) == bit1
=bit1,bit2 flags == (bit1|bit2)
bit-names:
locked error referenced uptodate
dirty lru active slab
writeback reclaim buddy mmap
anonymous swapcache swapbacked compound_head
compound_tail huge unevictable hwpoison
nopage reserved(r) mlocked(r) mappedtodisk(r)
private(r) private_2(r) owner_private(r) arch(r)
uncached(r) readahead(o) slob_free(o) slub_frozen(o)
slub_debug(o)
(r) raw mode bits (o) overloaded bits
# ./page-types
flags page-count MB symbolic-flags long-symbolic-flags
0x0000000000000000 487369 1903 _________________________________
0x0000000000000014 5 0 __R_D____________________________ referenced,dirty
0x0000000000000020 1 0 _____l___________________________ lru
0x0000000000000024 34 0 __R__l___________________________ referenced,lru
0x0000000000000028 3838 14 ___U_l___________________________ uptodate,lru
0x0001000000000028 48 0 ___U_l_______________________I___ uptodate,lru,readahead
0x000000000000002c 6478 25 __RU_l___________________________ referenced,uptodate,lru
0x000100000000002c 47 0 __RU_l_______________________I___ referenced,uptodate,lru,readahead
0x0000000000000040 8344 32 ______A__________________________ active
0x0000000000000060 1 0 _____lA__________________________ lru,active
0x0000000000000068 348 1 ___U_lA__________________________ uptodate,lru,active
0x0001000000000068 12 0 ___U_lA______________________I___ uptodate,lru,active,readahead
0x000000000000006c 988 3 __RU_lA__________________________ referenced,uptodate,lru,active
0x000100000000006c 48 0 __RU_lA______________________I___ referenced,uptodate,lru,active,readahead
0x0000000000004078 1 0 ___UDlA_______b__________________ uptodate,dirty,lru,active,swapbacked
0x000000000000407c 34 0 __RUDlA_______b__________________ referenced,uptodate,dirty,lru,active,swapbacked
0x0000000000000400 503 1 __________B______________________ buddy
0x0000000000000804 1 0 __R________M_____________________ referenced,mmap
0x0000000000000828 1029 4 ___U_l_____M_____________________ uptodate,lru,mmap
0x0001000000000828 43 0 ___U_l_____M_________________I___ uptodate,lru,mmap,readahead
0x000000000000082c 382 1 __RU_l_____M_____________________ referenced,uptodate,lru,mmap
0x000100000000082c 12 0 __RU_l_____M_________________I___ referenced,uptodate,lru,mmap,readahead
0x0000000000000868 192 0 ___U_lA____M_____________________ uptodate,lru,active,mmap
0x0001000000000868 12 0 ___U_lA____M_________________I___ uptodate,lru,active,mmap,readahead
0x000000000000086c 800 3 __RU_lA____M_____________________ referenced,uptodate,lru,active,mmap
0x000100000000086c 31 0 __RU_lA____M_________________I___ referenced,uptodate,lru,active,mmap,readahead
0x0000000000004878 2 0 ___UDlA____M__b__________________ uptodate,dirty,lru,active,mmap,swapbacked
0x0000000000001000 492 1 ____________a____________________ anonymous
0x0000000000005808 4 0 ___U_______Ma_b__________________ uptodate,mmap,anonymous,swapbacked
0x0000000000005868 2839 11 ___U_lA____Ma_b__________________ uptodate,lru,active,mmap,anonymous,swapbacked
0x000000000000586c 30 0 __RU_lA____Ma_b__________________ referenced,uptodate,lru,active,mmap,anonymous,swapbacked
total 513968 2007
# ./page-types -r
flags page-count MB symbolic-flags long-symbolic-flags
0x0000000000000000 468002 1828 _________________________________
0x0000000100000000 19102 74 _____________________r___________ reserved
0x0000000000008000 41 0 _______________H_________________ compound_head
0x0000000000010000 188 0 ________________T________________ compound_tail
0x0000000000008014 1 0 __R_D__________H_________________ referenced,dirty,compound_head
0x0000000000010014 4 0 __R_D___________T________________ referenced,dirty,compound_tail
0x0000000000000020 1 0 _____l___________________________ lru
0x0000000800000024 34 0 __R__l__________________P________ referenced,lru,private
0x0000000000000028 3794 14 ___U_l___________________________ uptodate,lru
0x0001000000000028 46 0 ___U_l_______________________I___ uptodate,lru,readahead
0x0000000400000028 44 0 ___U_l_________________d_________ uptodate,lru,mappedtodisk
0x0001000400000028 2 0 ___U_l_________________d_____I___ uptodate,lru,mappedtodisk,readahead
0x000000000000002c 6434 25 __RU_l___________________________ referenced,uptodate,lru
0x000100000000002c 47 0 __RU_l_______________________I___ referenced,uptodate,lru,readahead
0x000000040000002c 14 0 __RU_l_________________d_________ referenced,uptodate,lru,mappedtodisk
0x000000080000002c 30 0 __RU_l__________________P________ referenced,uptodate,lru,private
0x0000000800000040 8124 31 ______A_________________P________ active,private
0x0000000000000040 219 0 ______A__________________________ active
0x0000000800000060 1 0 _____lA_________________P________ lru,active,private
0x0000000000000068 322 1 ___U_lA__________________________ uptodate,lru,active
0x0001000000000068 12 0 ___U_lA______________________I___ uptodate,lru,active,readahead
0x0000000400000068 13 0 ___U_lA________________d_________ uptodate,lru,active,mappedtodisk
0x0000000800000068 12 0 ___U_lA_________________P________ uptodate,lru,active,private
0x000000000000006c 977 3 __RU_lA__________________________ referenced,uptodate,lru,active
0x000100000000006c 48 0 __RU_lA______________________I___ referenced,uptodate,lru,active,readahead
0x000000040000006c 5 0 __RU_lA________________d_________ referenced,uptodate,lru,active,mappedtodisk
0x000000080000006c 3 0 __RU_lA_________________P________ referenced,uptodate,lru,active,private
0x0000000c0000006c 3 0 __RU_lA________________dP________ referenced,uptodate,lru,active,mappedtodisk,private
0x0000000c00000068 1 0 ___U_lA________________dP________ uptodate,lru,active,mappedtodisk,private
0x0000000000004078 1 0 ___UDlA_______b__________________ uptodate,dirty,lru,active,swapbacked
0x000000000000407c 34 0 __RUDlA_______b__________________ referenced,uptodate,dirty,lru,active,swapbacked
0x0000000000000400 538 2 __________B______________________ buddy
0x0000000000000804 1 0 __R________M_____________________ referenced,mmap
0x0000000000000828 1029 4 ___U_l_____M_____________________ uptodate,lru,mmap
0x0001000000000828 43 0 ___U_l_____M_________________I___ uptodate,lru,mmap,readahead
0x000000000000082c 382 1 __RU_l_____M_____________________ referenced,uptodate,lru,mmap
0x000100000000082c 12 0 __RU_l_____M_________________I___ referenced,uptodate,lru,mmap,readahead
0x0000000000000868 192 0 ___U_lA____M_____________________ uptodate,lru,active,mmap
0x0001000000000868 12 0 ___U_lA____M_________________I___ uptodate,lru,active,mmap,readahead
0x000000000000086c 800 3 __RU_lA____M_____________________ referenced,uptodate,lru,active,mmap
0x000100000000086c 31 0 __RU_lA____M_________________I___ referenced,uptodate,lru,active,mmap,readahead
0x0000000000004878 2 0 ___UDlA____M__b__________________ uptodate,dirty,lru,active,mmap,swapbacked
0x0000000000001000 492 1 ____________a____________________ anonymous
0x0000000000005008 2 0 ___U________a_b__________________ uptodate,anonymous,swapbacked
0x0000000000005808 4 0 ___U_______Ma_b__________________ uptodate,mmap,anonymous,swapbacked
0x000000000000580c 1 0 __RU_______Ma_b__________________ referenced,uptodate,mmap,anonymous,swapbacked
0x0000000000005868 2839 11 ___U_lA____Ma_b__________________ uptodate,lru,active,mmap,anonymous,swapbacked
0x000000000000586c 29 0 __RU_lA____Ma_b__________________ referenced,uptodate,lru,active,mmap,anonymous,swapbacked
total 513968 2007
# ./page-types --raw --list --no-summary --bits reserved
offset count flags
0 15 _____________________r___________
31 4 _____________________r___________
159 97 _____________________r___________
4096 2067 _____________________r___________
6752 2390 _____________________r___________
9355 3 _____________________r___________
9728 14526 _____________________r___________
This patch:
Introduce PageHuge(), which identifies huge/gigantic pages by their
dedicated compound destructor functions.
Also move prep_compound_gigantic_page() to hugetlb.c and make
__free_pages_ok() non-static.
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Matt Mackall <mpm@selenic.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
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KOSAKI Motohiro
|
092cead617 |
page allocator: move free_page_mlock() to page_alloc.c
Currently, free_page_mlock() is only called from page_alloc.c. Thus, we can move it to page_alloc.c. Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Mel Gorman
|
da456f14d2 |
page allocator: do not disable interrupts in free_page_mlock()
free_page_mlock() tests and clears PG_mlocked using locked versions of the bit operations. If set, it disables interrupts to update counters and this happens on every page free even though interrupts are disabled very shortly afterwards a second time. This is wasteful. This patch splits what free_page_mlock() does. The bit check is still made. However, the update of counters is delayed until the interrupts are disabled and the non-lock version for clearing the bit is used. One potential weirdness with this split is that the counters do not get updated if the bad_page() check is triggered but a system showing bad pages is getting screwed already. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Acked-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
David Howells
|
33925b25d2 |
nommu: there is no mlock() for NOMMU, so don't provide the bits
The mlock() facility does not exist for NOMMU since all mappings are effectively locked anyway, so we don't make the bits available when they're not useful. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Greg Ungerer <gerg@snapgear.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Enrik Berkhan <Enrik.Berkhan@ge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Ying Han
|
4779280d1e |
mm: make get_user_pages() interruptible
The initial implementation of checking TIF_MEMDIE covers the cases of OOM killing. If the process has been OOM killed, the TIF_MEMDIE is set and it return immediately. This patch includes: 1. add the case that the SIGKILL is sent by user processes. The process can try to get_user_pages() unlimited memory even if a user process has sent a SIGKILL to it(maybe a monitor find the process exceed its memory limit and try to kill it). In the old implementation, the SIGKILL won't be handled until the get_user_pages() returns. 2. change the return value to be ERESTARTSYS. It makes no sense to return ENOMEM if the get_user_pages returned by getting a SIGKILL signal. Considering the general convention for a system call interrupted by a signal is ERESTARTNOSYS, so the current return value is consistant to that. Lee: An unfortunate side effect of "make-get_user_pages-interruptible" is that it prevents a SIGKILL'd task from munlock-ing pages that it had mlocked, resulting in freeing of mlocked pages. Freeing of mlocked pages, in itself, is not so bad. We just count them now--altho' I had hoped to remove this stat and add PG_MLOCKED to the free pages flags check. However, consider pages in shared libraries mapped by more than one task that a task mlocked--e.g., via mlockall(). If the task that mlocked the pages exits via SIGKILL, these pages would be left mlocked and unevictable. Proposed fix: Add another GUP flag to ignore sigkill when calling get_user_pages from munlock()--similar to Kosaki Motohiro's 'IGNORE_VMA_PERMISSIONS flag for the same purpose. We are not actually allocating memory in this case, which "make-get_user_pages-interruptible" intends to avoid. We're just munlocking pages that are already resident and mapped, and we're reusing get_user_pages() to access those pages. ?? Maybe we should combine 'IGNORE_VMA_PERMISSIONS and '_IGNORE_SIGKILL into a single flag: GUP_FLAGS_MUNLOCK ??? [Lee.Schermerhorn@hp.com: ignore sigkill in get_user_pages during munlock] Signed-off-by: Paul Menage <menage@google.com> Signed-off-by: Ying Han <yinghan@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Hugh Dickins <hugh@veritas.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Rohit Seth <rohitseth@google.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
|
|
Hugh Dickins
|
22b31eec63 |
badpage: vm_normal_page use print_bad_pte
print_bad_pte() is so far being called only when zap_pte_range() finds negative page_mapcount, or there's a fault on a pte_file where it does not belong. That's weak coverage when we suspect pagetable corruption. Originally, it was called when vm_normal_page() found an invalid pfn: but pfn_valid is expensive on some architectures and configurations, so 2.6.24 put that under CONFIG_DEBUG_VM (which doesn't help in the field), then 2.6.26 replaced it by a VM_BUG_ON (likewise). Reinstate the print_bad_pte() in vm_normal_page(), but use a cheaper test than pfn_valid(): memmap_init_zone() (used in bootup and hotplug) keep a __read_mostly note of the highest_memmap_pfn, vm_normal_page() then check pfn against that. We could call this pfn_plausible() or pfn_sane(), but I doubt we'll need it elsewhere: of course it's not reliable, but gives much stronger pagetable validation on many boxes. Also use print_bad_pte() when the pte_special bit is found outside a VM_PFNMAP or VM_MIXEDMAP area, instead of VM_BUG_ON. Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andy Whitcroft
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18229df5b6 |
hugetlb: pull gigantic page initialisation out of the default path
As we can determine exactly when a gigantic page is in use we can optimise the common regular page cases by pulling out gigantic page initialisation into its own function. As gigantic pages are never released to buddy we do not need a destructor. This effectivly reverts the previous change to the main buddy allocator. It also adds a paranoid check to ensure we never release gigantic pages from hugetlbfs to the main buddy. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Jon Tollefson <kniht@linux.vnet.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: <stable@kernel.org> [2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Andy Whitcroft
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69d177c2fc |
hugetlbfs: handle pages higher order than MAX_ORDER
When working with hugepages, hugetlbfs assumes that those hugepages are smaller than MAX_ORDER. Specifically it assumes that the mem_map is contigious and uses that to optimise access to the elements of the mem_map that represent the hugepage. Gigantic pages (such as 16GB pages on powerpc) by definition are of greater order than MAX_ORDER (larger than MAX_ORDER_NR_PAGES in size). This means that we can no longer make use of the buddy alloctor guarentees for the contiguity of the mem_map, which ensures that the mem_map is at least contigious for maximmally aligned areas of MAX_ORDER_NR_PAGES pages. This patch adds new mem_map accessors and iterator helpers which handle any discontiguity at MAX_ORDER_NR_PAGES boundaries. It then uses these to implement gigantic page versions of copy_huge_page and clear_huge_page, and to allow follow_hugetlb_page handle gigantic pages. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Jon Tollefson <kniht@linux.vnet.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: <stable@kernel.org> [2.6.27.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Lee Schermerhorn
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985737cf2e |
mlock: count attempts to free mlocked page
Allow free of mlock()ed pages. This shouldn't happen, but during developement, it occasionally did. This patch allows us to survive that condition, while keeping the statistics and events correct for debug. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Nick Piggin
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5344b7e648 |
vmstat: mlocked pages statistics
Add NR_MLOCK zone page state, which provides a (conservative) count of mlocked pages (actually, the number of mlocked pages moved off the LRU). Reworked by lts to fit in with the modified mlock page support in the Reclaim Scalability series. [kosaki.motohiro@jp.fujitsu.com: fix incorrect Mlocked field of /proc/meminfo] [lee.schermerhorn@hp.com: mlocked-pages: add event counting with statistics] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Rik van Riel
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ba470de431 |
mmap: handle mlocked pages during map, remap, unmap
Originally by Nick Piggin <npiggin@suse.de> Remove mlocked pages from the LRU using "unevictable infrastructure" during mmap(), munmap(), mremap() and truncate(). Try to move back to normal LRU lists on munmap() when last mlocked mapping removed. Remove PageMlocked() status when page truncated from file. [akpm@linux-foundation.org: cleanup] [kamezawa.hiroyu@jp.fujitsu.com: fix double unlock_page()] [kosaki.motohiro@jp.fujitsu.com: split LRU: munlock rework] [lee.schermerhorn@hp.com: mlock: fix __mlock_vma_pages_range comment block] [akpm@linux-foundation.org: remove bogus kerneldoc token] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamewzawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Nick Piggin
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b291f00039 |
mlock: mlocked pages are unevictable
Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin <npiggin@suse.de> splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Lee Schermerhorn
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894bc31041 |
Unevictable LRU Infrastructure
When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> 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> |