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317 commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Michael S. Tsirkin
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9efeccacd3 |
linux: drop __bitwise__ everywhere
__bitwise__ used to mean "yes, please enable sparse checks unconditionally", but now that we dropped __CHECK_ENDIAN__ __bitwise is exactly the same. There aren't many users, replace it by __bitwise everywhere. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Stefan Schmidt <stefan@osg.samsung.com> Acked-by: Krzysztof Kozlowski <krzk@kernel.org> Akced-by: Lee Duncan <lduncan@suse.com> |
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Linus Torvalds
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9dcb8b685f |
mm: remove per-zone hashtable of bitlock waitqueues
The per-zone waitqueues exist because of a scalability issue with the
page waitqueues on some NUMA machines, but it turns out that they hurt
normal loads, and now with the vmalloced stacks they also end up
breaking gfs2 that uses a bit_wait on a stack object:
wait_on_bit(&gh->gh_iflags, HIF_WAIT, TASK_UNINTERRUPTIBLE)
where 'gh' can be a reference to the local variable 'mount_gh' on the
stack of fill_super().
The reason the per-zone hash table breaks for this case is that there is
no "zone" for virtual allocations, and trying to look up the physical
page to get at it will fail (with a BUG_ON()).
It turns out that I actually complained to the mm people about the
per-zone hash table for another reason just a month ago: the zone lookup
also hurts the regular use of "unlock_page()" a lot, because the zone
lookup ends up forcing several unnecessary cache misses and generates
horrible code.
As part of that earlier discussion, we had a much better solution for
the NUMA scalability issue - by just making the page lock have a
separate contention bit, the waitqueue doesn't even have to be looked at
for the normal case.
Peter Zijlstra already has a patch for that, but let's see if anybody
even notices. In the meantime, let's fix the actual gfs2 breakage by
simplifying the bitlock waitqueues and removing the per-zone issue.
Reported-by: Andreas Gruenbacher <agruenba@redhat.com>
Tested-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Mel Gorman
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6aa303defb |
mm, vmscan: only allocate and reclaim from zones with pages managed by the buddy allocator
Firmware Assisted Dump (FA_DUMP) on ppc64 reserves substantial amounts
of memory when booting a secondary kernel. Srikar Dronamraju reported
that multiple nodes may have no memory managed by the buddy allocator
but still return true for populated_zone().
Commit
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Linus Torvalds
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1eccfa090e |
Implements HARDENED_USERCOPY verification of copy_to_user/copy_from_user
bounds checking for most architectures on SLAB and SLUB. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Kees Cook <kees@outflux.net> iQIcBAABCgAGBQJXl9tlAAoJEIly9N/cbcAm5BoP/ikTtDp2bFw1sn92yHTnIWzl O+dcKVAeRgjfnSvPfb1JITpaM58exQSaDsPBeR0DbVzU1zDdhLcwHHiQupFh98Ka vBZthbrlL/u4NB26enEEW0iyA32BsxYBMnIu0z5ux9RbZflmQwGQ0c0rvy3dJ7/b FzB5ayVST5y/a0m6/sImeeExh78GU9rsMb1XmJRMwlJAy6miDz/F9TP0LnuW6PhG J5XC99ygNJS1pQBLACRsrZw6ImgBxXnWCok6tWPMxFfD+rJBU2//wqS+HozyMWHL iYP7+ytVo/ZVok4114X/V4Oof3a6wqgpBuYrivJ228QO+UsLYbYLo6sZ8kRK7VFm 9GgHo/8rWB1T9lBbSaa7UL5r0dVNNLjFGS42vwV+YlgUMQ1A35VRojO0jUnJSIQU Ug1IxKmylLd0nEcwD8/l3DXeQABsfL8GsoKW0OtdTZtW4RND4gzq34LK6t7hvayF kUkLg1OLNdUJwOi16M/rhugwYFZIMfoxQtjkRXKWN4RZ2QgSHnx2lhqNmRGPAXBG uy21wlzUTfLTqTpoeOyHzJwyF2qf2y4nsziBMhvmlrUvIzW1LIrYUKCNT4HR8Sh5 lC2WMGYuIqaiu+NOF3v6CgvKd9UW+mxMRyPEybH8mEgfm+FLZlWABiBjIUpSEZuB JFfuMv1zlljj/okIQRg8 =USIR -----END PGP SIGNATURE----- Merge tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux Pull usercopy protection from Kees Cook: "Tbhis implements HARDENED_USERCOPY verification of copy_to_user and copy_from_user bounds checking for most architectures on SLAB and SLUB" * tag 'usercopy-v4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: mm: SLUB hardened usercopy support mm: SLAB hardened usercopy support s390/uaccess: Enable hardened usercopy sparc/uaccess: Enable hardened usercopy powerpc/uaccess: Enable hardened usercopy ia64/uaccess: Enable hardened usercopy arm64/uaccess: Enable hardened usercopy ARM: uaccess: Enable hardened usercopy x86/uaccess: Enable hardened usercopy mm: Hardened usercopy mm: Implement stack frame object validation mm: Add is_migrate_cma_page |
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Andy Lutomirski
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d30dd8be06 |
mm: track NR_KERNEL_STACK in KiB instead of number of stacks
Currently, NR_KERNEL_STACK tracks the number of kernel stacks in a zone. This only makes sense if each kernel stack exists entirely in one zone, and allowing vmapped stacks could break this assumption. Since frv has THREAD_SIZE < PAGE_SIZE, we need to track kernel stack allocations in a unit that divides both THREAD_SIZE and PAGE_SIZE on all architectures. Keep it simple and use KiB. Link: http://lkml.kernel.org/r/083c71e642c5fa5f1b6898902e1b2db7b48940d4.1468523549.git.luto@kernel.org Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.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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5a1c84b404 |
mm: remove reclaim and compaction retry approximations
If per-zone LRU accounting is available then there is no point approximating whether reclaim and compaction should retry based on pgdat statistics. This is effectively a revert of "mm, vmstat: remove zone and node double accounting by approximating retries" with the difference that inactive/active stats are still available. This preserves the history of why the approximation was retried and why it had to be reverted to handle OOM kills on 32-bit systems. Link: http://lkml.kernel.org/r/1469110261-7365-4-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Minchan Kim <minchan@kernel.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Minchan Kim
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71c799f498 |
mm: add per-zone lru list stat
When I did stress test with hackbench, I got OOM message frequently which didn't ever happen in zone-lru. gfp_mask=0x26004c0(GFP_KERNEL|__GFP_REPEAT|__GFP_NOTRACK), order=0 .. .. __alloc_pages_nodemask+0xe52/0xe60 ? new_slab+0x39c/0x3b0 new_slab+0x39c/0x3b0 ___slab_alloc.constprop.87+0x6da/0x840 ? __alloc_skb+0x3c/0x260 ? _raw_spin_unlock_irq+0x27/0x60 ? trace_hardirqs_on_caller+0xec/0x1b0 ? finish_task_switch+0xa6/0x220 ? poll_select_copy_remaining+0x140/0x140 __slab_alloc.isra.81.constprop.86+0x40/0x6d ? __alloc_skb+0x3c/0x260 kmem_cache_alloc+0x22c/0x260 ? __alloc_skb+0x3c/0x260 __alloc_skb+0x3c/0x260 alloc_skb_with_frags+0x4e/0x1a0 sock_alloc_send_pskb+0x16a/0x1b0 ? wait_for_unix_gc+0x31/0x90 ? alloc_set_pte+0x2ad/0x310 unix_stream_sendmsg+0x28d/0x340 sock_sendmsg+0x2d/0x40 sock_write_iter+0x6c/0xc0 __vfs_write+0xc0/0x120 vfs_write+0x9b/0x1a0 ? __might_fault+0x49/0xa0 SyS_write+0x44/0x90 do_fast_syscall_32+0xa6/0x1e0 sysenter_past_esp+0x45/0x74 Mem-Info: active_anon:104698 inactive_anon:105791 isolated_anon:192 active_file:433 inactive_file:283 isolated_file:22 unevictable:0 dirty:0 writeback:296 unstable:0 slab_reclaimable:6389 slab_unreclaimable:78927 mapped:474 shmem:0 pagetables:101426 bounce:0 free:10518 free_pcp:334 free_cma:0 Node 0 active_anon:418792kB inactive_anon:423164kB active_file:1732kB inactive_file:1132kB unevictable:0kB isolated(anon):768kB isolated(file):88kB mapped:1896kB dirty:0kB writeback:1184kB shmem:0kB writeback_tmp:0kB unstable:0kB pages_scanned:1478632 all_unreclaimable? yes DMA free:3304kB min:68kB low:84kB high:100kB present:15992kB managed:15916kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:4088kB kernel_stack:0kB pagetables:2480kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB lowmem_reserve[]: 0 809 1965 1965 Normal free:3436kB min:3604kB low:4504kB high:5404kB present:897016kB managed:858460kB mlocked:0kB slab_reclaimable:25556kB slab_unreclaimable:311712kB kernel_stack:164608kB pagetables:30844kB bounce:0kB free_pcp:620kB local_pcp:104kB free_cma:0kB lowmem_reserve[]: 0 0 9247 9247 HighMem free:33808kB min:512kB low:1796kB high:3080kB present:1183736kB managed:1183736kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:372252kB bounce:0kB free_pcp:428kB local_pcp:72kB free_cma:0kB lowmem_reserve[]: 0 0 0 0 DMA: 2*4kB (UM) 2*8kB (UM) 0*16kB 1*32kB (U) 1*64kB (U) 2*128kB (UM) 1*256kB (U) 1*512kB (M) 0*1024kB 1*2048kB (U) 0*4096kB = 3192kB Normal: 33*4kB (MH) 79*8kB (ME) 11*16kB (M) 4*32kB (M) 2*64kB (ME) 2*128kB (EH) 7*256kB (EH) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 3244kB HighMem: 2590*4kB (UM) 1568*8kB (UM) 491*16kB (UM) 60*32kB (UM) 6*64kB (M) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 33064kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB 25121 total pagecache pages 24160 pages in swap cache Swap cache stats: add 86371, delete 62211, find 42865/60187 Free swap = 4015560kB Total swap = 4192252kB 524186 pages RAM 295934 pages HighMem/MovableOnly 9658 pages reserved 0 pages cma reserved The order-0 allocation for normal zone failed while there are a lot of reclaimable memory(i.e., anonymous memory with free swap). I wanted to analyze the problem but it was hard because we removed per-zone lru stat so I couldn't know how many of anonymous memory there are in normal/dma zone. When we investigate OOM problem, reclaimable memory count is crucial stat to find a problem. Without it, it's hard to parse the OOM message so I believe we should keep it. With per-zone lru stat, gfp_mask=0x26004c0(GFP_KERNEL|__GFP_REPEAT|__GFP_NOTRACK), order=0 Mem-Info: active_anon:101103 inactive_anon:102219 isolated_anon:0 active_file:503 inactive_file:544 isolated_file:0 unevictable:0 dirty:0 writeback:34 unstable:0 slab_reclaimable:6298 slab_unreclaimable:74669 mapped:863 shmem:0 pagetables:100998 bounce:0 free:23573 free_pcp:1861 free_cma:0 Node 0 active_anon:404412kB inactive_anon:409040kB active_file:2012kB inactive_file:2176kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:3452kB dirty:0kB writeback:136kB shmem:0kB writeback_tmp:0kB unstable:0kB pages_scanned:1320845 all_unreclaimable? yes DMA free:3296kB min:68kB low:84kB high:100kB active_anon:5540kB inactive_anon:0kB active_file:0kB inactive_file:0kB present:15992kB managed:15916kB mlocked:0kB slab_reclaimable:248kB slab_unreclaimable:2628kB kernel_stack:792kB pagetables:2316kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB lowmem_reserve[]: 0 809 1965 1965 Normal free:3600kB min:3604kB low:4504kB high:5404kB active_anon:86304kB inactive_anon:0kB active_file:160kB inactive_file:376kB present:897016kB managed:858524kB mlocked:0kB slab_reclaimable:24944kB slab_unreclaimable:296048kB kernel_stack:163832kB pagetables:35892kB bounce:0kB free_pcp:3076kB local_pcp:656kB free_cma:0kB lowmem_reserve[]: 0 0 9247 9247 HighMem free:86156kB min:512kB low:1796kB high:3080kB active_anon:312852kB inactive_anon:410024kB active_file:1924kB inactive_file:2012kB present:1183736kB managed:1183736kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:365784kB bounce:0kB free_pcp:3868kB local_pcp:720kB free_cma:0kB lowmem_reserve[]: 0 0 0 0 DMA: 8*4kB (UM) 8*8kB (UM) 4*16kB (M) 2*32kB (UM) 2*64kB (UM) 1*128kB (M) 3*256kB (UME) 2*512kB (UE) 1*1024kB (E) 0*2048kB 0*4096kB = 3296kB Normal: 240*4kB (UME) 160*8kB (UME) 23*16kB (ME) 3*32kB (UE) 3*64kB (UME) 2*128kB (ME) 1*256kB (U) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 3408kB HighMem: 10942*4kB (UM) 3102*8kB (UM) 866*16kB (UM) 76*32kB (UM) 11*64kB (UM) 4*128kB (UM) 1*256kB (M) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 86344kB Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB 54409 total pagecache pages 53215 pages in swap cache Swap cache stats: add 300982, delete 247765, find 157978/226539 Free swap = 3803244kB Total swap = 4192252kB 524186 pages RAM 295934 pages HighMem/MovableOnly 9642 pages reserved 0 pages cma reserved With that, we can see normal zone has a 86M reclaimable memory so we can know something goes wrong(I will fix the problem in next patch) in reclaim. [mgorman@techsingularity.net: rename zone LRU stats in /proc/vmstat] Link: http://lkml.kernel.org/r/20160725072300.GK10438@techsingularity.net Link: http://lkml.kernel.org/r/1469110261-7365-2-git-send-email-mgorman@techsingularity.net Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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bca6759258 |
mm, vmstat: remove zone and node double accounting by approximating retries
The number of LRU pages, dirty pages and writeback pages must be
accounted for on both zones and nodes because of the reclaim retry
logic, compaction retry logic and highmem calculations all depending on
per-zone stats.
Many lowmem allocations are immune from OOM kill due to a check in
__alloc_pages_may_oom for (ac->high_zoneidx < ZONE_NORMAL) since commit
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Mel Gorman
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e6cbd7f2ef |
mm, page_alloc: remove fair zone allocation policy
The fair zone allocation policy interleaves allocation requests between zones to avoid an age inversion problem whereby new pages are reclaimed to balance a zone. Reclaim is now node-based so this should no longer be an issue and the fair zone allocation policy is not free. This patch removes it. Link: http://lkml.kernel.org/r/1467970510-21195-30-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.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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a5f5f91da6 |
mm: convert zone_reclaim to node_reclaim
As reclaim is now per-node based, convert zone_reclaim to be node_reclaim. It is possible that a node will be reclaimed multiple times if it has multiple zones but this is unavoidable without caching all nodes traversed so far. The documentation and interface to userspace is the same from a configuration perspective and will will be similar in behaviour unless the node-local allocation requests were also limited to lower zones. Link: http://lkml.kernel.org/r/1467970510-21195-24-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.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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c4a25635b6 |
mm: move vmscan writes and file write accounting to the node
As reclaim is now node-based, it follows that page write activity due to page reclaim should also be accounted for on the node. For consistency, also account page writes and page dirtying on a per-node basis. After this patch, there are a few remaining zone counters that may appear strange but are fine. NUMA stats are still per-zone as this is a user-space interface that tools consume. NR_MLOCK, NR_SLAB_*, NR_PAGETABLE, NR_KERNEL_STACK and NR_BOUNCE are all allocations that potentially pin low memory and cannot trivially be reclaimed on demand. This information is still useful for debugging a page allocation failure warning. Link: http://lkml.kernel.org/r/1467970510-21195-21-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.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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11fb998986 |
mm: move most file-based accounting to the node
There are now a number of accounting oddities such as mapped file pages being accounted for on the node while the total number of file pages are accounted on the zone. This can be coped with to some extent but it's confusing so this patch moves the relevant file-based accounted. Due to throttling logic in the page allocator for reliable OOM detection, it is still necessary to track dirty and writeback pages on a per-zone basis. [mgorman@techsingularity.net: fix NR_ZONE_WRITE_PENDING accounting] Link: http://lkml.kernel.org/r/1468404004-5085-5-git-send-email-mgorman@techsingularity.net Link: http://lkml.kernel.org/r/1467970510-21195-20-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.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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4b9d0fab71 |
mm: rename NR_ANON_PAGES to NR_ANON_MAPPED
NR_FILE_PAGES is the number of file pages. NR_FILE_MAPPED is the number of mapped file pages. NR_ANON_PAGES is the number of mapped anon pages. This is unhelpful naming as it's easy to confuse NR_FILE_MAPPED and NR_ANON_PAGES for mapped pages. This patch renames NR_ANON_PAGES so we have NR_FILE_PAGES is the number of file pages. NR_FILE_MAPPED is the number of mapped file pages. NR_ANON_MAPPED is the number of mapped anon pages. Link: http://lkml.kernel.org/r/1467970510-21195-19-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.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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50658e2e04 |
mm: move page mapped accounting to the node
Reclaim makes decisions based on the number of pages that are mapped but it's mixing node and zone information. Account NR_FILE_MAPPED and NR_ANON_PAGES pages on the node. Link: http://lkml.kernel.org/r/1467970510-21195-18-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.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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281e37265f |
mm, page_alloc: consider dirtyable memory in terms of nodes
Historically dirty pages were spread among zones but now that LRUs are per-node it is more appropriate to consider dirty pages in a node. Link: http://lkml.kernel.org/r/1467970510-21195-17-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.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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1e6b10857f |
mm, workingset: make working set detection node-aware
Working set and refault detection is still zone-based, fix it. Link: http://lkml.kernel.org/r/1467970510-21195-16-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Mel Gorman
|
a9dd0a8310 |
mm, vmscan: make shrink_node decisions more node-centric
Earlier patches focused on having direct reclaim and kswapd use data that is node-centric for reclaiming but shrink_node() itself still uses too much zone information. This patch removes unnecessary zone-based information with the most important decision being whether to continue reclaim or not. Some memcg APIs are adjusted as a result even though memcg itself still uses some zone information. [mgorman@techsingularity.net: optimization] Link: http://lkml.kernel.org/r/1468588165-12461-2-git-send-email-mgorman@techsingularity.net Link: http://lkml.kernel.org/r/1467970510-21195-14-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Mel Gorman
|
38087d9b03 |
mm, vmscan: simplify the logic deciding whether kswapd sleeps
kswapd goes through some complex steps trying to figure out if it should stay awake based on the classzone_idx and the requested order. It is unnecessarily complex and passes in an invalid classzone_idx to balance_pgdat(). What matters most of all is whether a larger order has been requsted and whether kswapd successfully reclaimed at the previous order. This patch irons out the logic to check just that and the end result is less headache inducing. Link: http://lkml.kernel.org/r/1467970510-21195-10-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Mel Gorman
|
0f66114893 |
mm, mmzone: clarify the usage of zone padding
Zone padding separates write-intensive fields used by page allocation, compaction and vmstats but the comments are a little misleading and need clarification. Link: http://lkml.kernel.org/r/1467970510-21195-5-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Mel Gorman
|
599d0c954f |
mm, vmscan: move LRU lists to node
This moves the LRU lists from the zone to the node and related data such as counters, tracing, congestion tracking and writeback tracking. Unfortunately, due to reclaim and compaction retry logic, it is necessary to account for the number of LRU pages on both zone and node logic. Most reclaim logic is based on the node counters but the retry logic uses the zone counters which do not distinguish inactive and active sizes. It would be possible to leave the LRU counters on a per-zone basis but it's a heavier calculation across multiple cache lines that is much more frequent than the retry checks. Other than the LRU counters, this is mostly a mechanical patch but note that it introduces a number of anomalies. For example, the scans are per-zone but using per-node counters. We also mark a node as congested when a zone is congested. This causes weird problems that are fixed later but is easier to review. In the event that there is excessive overhead on 32-bit systems due to the nodes being on LRU then there are two potential solutions 1. Long-term isolation of highmem pages when reclaim is lowmem When pages are skipped, they are immediately added back onto the LRU list. If lowmem reclaim persisted for long periods of time, the same highmem pages get continually scanned. The idea would be that lowmem keeps those pages on a separate list until a reclaim for highmem pages arrives that splices the highmem pages back onto the LRU. It potentially could be implemented similar to the UNEVICTABLE list. That would reduce the skip rate with the potential corner case is that highmem pages have to be scanned and reclaimed to free lowmem slab pages. 2. Linear scan lowmem pages if the initial LRU shrink fails This will break LRU ordering but may be preferable and faster during memory pressure than skipping LRU pages. Link: http://lkml.kernel.org/r/1467970510-21195-4-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Minchan Kim <minchan@kernel.org> Cc: Rik van Riel <riel@surriel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Mel Gorman
|
a52633d8e9 |
mm, vmscan: move lru_lock to the node
Node-based reclaim requires node-based LRUs and locking. This is a preparation patch that just moves the lru_lock to the node so later patches are easier to review. It is a mechanical change but note this patch makes contention worse because the LRU lock is hotter and direct reclaim and kswapd can contend on the same lock even when reclaiming from different zones. Link: http://lkml.kernel.org/r/1467970510-21195-3-git-send-email-mgorman@techsingularity.net Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Reviewed-by: Minchan Kim <minchan@kernel.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Rik van Riel <riel@surriel.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
|
75ef718405 |
mm, vmstat: add infrastructure for per-node vmstats
Patchset: "Move LRU page reclaim from zones to nodes v9"
This series moves LRUs from the zones to the node. While this is a
current rebase, the test results were based on mmotm as of June 23rd.
Conceptually, this series is simple but there are a lot of details.
Some of the broad motivations for this are;
1. The residency of a page partially depends on what zone the page was
allocated from. This is partially combatted by the fair zone allocation
policy but that is a partial solution that introduces overhead in the
page allocator paths.
2. Currently, reclaim on node 0 behaves slightly different to node 1. For
example, direct reclaim scans in zonelist order and reclaims even if
the zone is over the high watermark regardless of the age of pages
in that LRU. Kswapd on the other hand starts reclaim on the highest
unbalanced zone. A difference in distribution of file/anon pages due
to when they were allocated results can result in a difference in
again. While the fair zone allocation policy mitigates some of the
problems here, the page reclaim results on a multi-zone node will
always be different to a single-zone node.
it was scheduled on as a result.
3. kswapd and the page allocator scan zones in the opposite order to
avoid interfering with each other but it's sensitive to timing. This
mitigates the page allocator using pages that were allocated very recently
in the ideal case but it's sensitive to timing. When kswapd is allocating
from lower zones then it's great but during the rebalancing of the highest
zone, the page allocator and kswapd interfere with each other. It's worse
if the highest zone is small and difficult to balance.
4. slab shrinkers are node-based which makes it harder to identify the exact
relationship between slab reclaim and LRU reclaim.
The reason we have zone-based reclaim is that we used to have
large highmem zones in common configurations and it was necessary
to quickly find ZONE_NORMAL pages for reclaim. Today, this is much
less of a concern as machines with lots of memory will (or should) use
64-bit kernels. Combinations of 32-bit hardware and 64-bit hardware are
rare. Machines that do use highmem should have relatively low highmem:lowmem
ratios than we worried about in the past.
Conceptually, moving to node LRUs should be easier to understand. The
page allocator plays fewer tricks to game reclaim and reclaim behaves
similarly on all nodes.
The series has been tested on a 16 core UMA machine and a 2-socket 48
core NUMA machine. The UMA results are presented in most cases as the NUMA
machine behaved similarly.
pagealloc
---------
This is a microbenchmark that shows the benefit of removing the fair zone
allocation policy. It was tested uip to order-4 but only orders 0 and 1 are
shown as the other orders were comparable.
4.7.0-rc4 4.7.0-rc4
mmotm-20160623 nodelru-v9
Min total-odr0-1 490.00 ( 0.00%) 457.00 ( 6.73%)
Min total-odr0-2 347.00 ( 0.00%) 329.00 ( 5.19%)
Min total-odr0-4 288.00 ( 0.00%) 273.00 ( 5.21%)
Min total-odr0-8 251.00 ( 0.00%) 239.00 ( 4.78%)
Min total-odr0-16 234.00 ( 0.00%) 222.00 ( 5.13%)
Min total-odr0-32 223.00 ( 0.00%) 211.00 ( 5.38%)
Min total-odr0-64 217.00 ( 0.00%) 208.00 ( 4.15%)
Min total-odr0-128 214.00 ( 0.00%) 204.00 ( 4.67%)
Min total-odr0-256 250.00 ( 0.00%) 230.00 ( 8.00%)
Min total-odr0-512 271.00 ( 0.00%) 269.00 ( 0.74%)
Min total-odr0-1024 291.00 ( 0.00%) 282.00 ( 3.09%)
Min total-odr0-2048 303.00 ( 0.00%) 296.00 ( 2.31%)
Min total-odr0-4096 311.00 ( 0.00%) 309.00 ( 0.64%)
Min total-odr0-8192 316.00 ( 0.00%) 314.00 ( 0.63%)
Min total-odr0-16384 317.00 ( 0.00%) 315.00 ( 0.63%)
Min total-odr1-1 742.00 ( 0.00%) 712.00 ( 4.04%)
Min total-odr1-2 562.00 ( 0.00%) 530.00 ( 5.69%)
Min total-odr1-4 457.00 ( 0.00%) 433.00 ( 5.25%)
Min total-odr1-8 411.00 ( 0.00%) 381.00 ( 7.30%)
Min total-odr1-16 381.00 ( 0.00%) 356.00 ( 6.56%)
Min total-odr1-32 372.00 ( 0.00%) 346.00 ( 6.99%)
Min total-odr1-64 372.00 ( 0.00%) 343.00 ( 7.80%)
Min total-odr1-128 375.00 ( 0.00%) 351.00 ( 6.40%)
Min total-odr1-256 379.00 ( 0.00%) 351.00 ( 7.39%)
Min total-odr1-512 385.00 ( 0.00%) 355.00 ( 7.79%)
Min total-odr1-1024 386.00 ( 0.00%) 358.00 ( 7.25%)
Min total-odr1-2048 390.00 ( 0.00%) 362.00 ( 7.18%)
Min total-odr1-4096 390.00 ( 0.00%) 362.00 ( 7.18%)
Min total-odr1-8192 388.00 ( 0.00%) 363.00 ( 6.44%)
This shows a steady improvement throughout. The primary benefit is from
reduced system CPU usage which is obvious from the overall times;
4.7.0-rc4 4.7.0-rc4
mmotm-20160623nodelru-v8
User 189.19 191.80
System 2604.45 2533.56
Elapsed 2855.30 2786.39
The vmstats also showed that the fair zone allocation policy was definitely
removed as can be seen here;
4.7.0-rc3 4.7.0-rc3
mmotm-20160623 nodelru-v8
DMA32 allocs 28794729769 0
Normal allocs 48432501431 77227309877
Movable allocs 0 0
tiobench on ext4
----------------
tiobench is a benchmark that artifically benefits if old pages remain resident
while new pages get reclaimed. The fair zone allocation policy mitigates this
problem so pages age fairly. While the benchmark has problems, it is important
that tiobench performance remains constant as it implies that page aging
problems that the fair zone allocation policy fixes are not re-introduced.
4.7.0-rc4 4.7.0-rc4
mmotm-20160623 nodelru-v9
Min PotentialReadSpeed 89.65 ( 0.00%) 90.21 ( 0.62%)
Min SeqRead-MB/sec-1 82.68 ( 0.00%) 82.01 ( -0.81%)
Min SeqRead-MB/sec-2 72.76 ( 0.00%) 72.07 ( -0.95%)
Min SeqRead-MB/sec-4 75.13 ( 0.00%) 74.92 ( -0.28%)
Min SeqRead-MB/sec-8 64.91 ( 0.00%) 65.19 ( 0.43%)
Min SeqRead-MB/sec-16 62.24 ( 0.00%) 62.22 ( -0.03%)
Min RandRead-MB/sec-1 0.88 ( 0.00%) 0.88 ( 0.00%)
Min RandRead-MB/sec-2 0.95 ( 0.00%) 0.92 ( -3.16%)
Min RandRead-MB/sec-4 1.43 ( 0.00%) 1.34 ( -6.29%)
Min RandRead-MB/sec-8 1.61 ( 0.00%) 1.60 ( -0.62%)
Min RandRead-MB/sec-16 1.80 ( 0.00%) 1.90 ( 5.56%)
Min SeqWrite-MB/sec-1 76.41 ( 0.00%) 76.85 ( 0.58%)
Min SeqWrite-MB/sec-2 74.11 ( 0.00%) 73.54 ( -0.77%)
Min SeqWrite-MB/sec-4 80.05 ( 0.00%) 80.13 ( 0.10%)
Min SeqWrite-MB/sec-8 72.88 ( 0.00%) 73.20 ( 0.44%)
Min SeqWrite-MB/sec-16 75.91 ( 0.00%) 76.44 ( 0.70%)
Min RandWrite-MB/sec-1 1.18 ( 0.00%) 1.14 ( -3.39%)
Min RandWrite-MB/sec-2 1.02 ( 0.00%) 1.03 ( 0.98%)
Min RandWrite-MB/sec-4 1.05 ( 0.00%) 0.98 ( -6.67%)
Min RandWrite-MB/sec-8 0.89 ( 0.00%) 0.92 ( 3.37%)
Min RandWrite-MB/sec-16 0.92 ( 0.00%) 0.93 ( 1.09%)
4.7.0-rc4 4.7.0-rc4
mmotm-20160623 approx-v9
User 645.72 525.90
System 403.85 331.75
Elapsed 6795.36 6783.67
This shows that the series has little or not impact on tiobench which is
desirable and a reduction in system CPU usage. It indicates that the fair
zone allocation policy was removed in a manner that didn't reintroduce
one class of page aging bug. There were only minor differences in overall
reclaim activity
4.7.0-rc4 4.7.0-rc4
mmotm-20160623nodelru-v8
Minor Faults 645838 647465
Major Faults 573 640
Swap Ins 0 0
Swap Outs 0 0
DMA allocs 0 0
DMA32 allocs 46041453 44190646
Normal allocs 78053072 79887245
Movable allocs 0 0
Allocation stalls 24 67
Stall zone DMA 0 0
Stall zone DMA32 0 0
Stall zone Normal 0 2
Stall zone HighMem 0 0
Stall zone Movable 0 65
Direct pages scanned 10969 30609
Kswapd pages scanned 93375144 93492094
Kswapd pages reclaimed 93372243 93489370
Direct pages reclaimed 10969 30609
Kswapd efficiency 99% 99%
Kswapd velocity 13741.015 13781.934
Direct efficiency 100% 100%
Direct velocity 1.614 4.512
Percentage direct scans 0% 0%
kswapd activity was roughly comparable. There were differences in direct
reclaim activity but negligible in the context of the overall workload
(velocity of 4 pages per second with the patches applied, 1.6 pages per
second in the baseline kernel).
pgbench read-only large configuration on ext4
---------------------------------------------
pgbench is a database benchmark that can be sensitive to page reclaim
decisions. This also checks if removing the fair zone allocation policy
is safe
pgbench Transactions
4.7.0-rc4 4.7.0-rc4
mmotm-20160623 nodelru-v8
Hmean 1 188.26 ( 0.00%) 189.78 ( 0.81%)
Hmean 5 330.66 ( 0.00%) 328.69 ( -0.59%)
Hmean 12 370.32 ( 0.00%) 380.72 ( 2.81%)
Hmean 21 368.89 ( 0.00%) 369.00 ( 0.03%)
Hmean 30 382.14 ( 0.00%) 360.89 ( -5.56%)
Hmean 32 428.87 ( 0.00%) 432.96 ( 0.95%)
Negligible differences again. As with tiobench, overall reclaim activity
was comparable.
bonnie++ on ext4
----------------
No interesting performance difference, negligible differences on reclaim
stats.
paralleldd on ext4
------------------
This workload uses varying numbers of dd instances to read large amounts of
data from disk.
4.7.0-rc3 4.7.0-rc3
mmotm-20160623 nodelru-v9
Amean Elapsd-1 186.04 ( 0.00%) 189.41 ( -1.82%)
Amean Elapsd-3 192.27 ( 0.00%) 191.38 ( 0.46%)
Amean Elapsd-5 185.21 ( 0.00%) 182.75 ( 1.33%)
Amean Elapsd-7 183.71 ( 0.00%) 182.11 ( 0.87%)
Amean Elapsd-12 180.96 ( 0.00%) 181.58 ( -0.35%)
Amean Elapsd-16 181.36 ( 0.00%) 183.72 ( -1.30%)
4.7.0-rc4 4.7.0-rc4
mmotm-20160623 nodelru-v9
User 1548.01 1552.44
System 8609.71 8515.08
Elapsed 3587.10 3594.54
There is little or no change in performance but some drop in system CPU usage.
4.7.0-rc3 4.7.0-rc3
mmotm-20160623 nodelru-v9
Minor Faults 362662 367360
Major Faults 1204 1143
Swap Ins 22 0
Swap Outs 2855 1029
DMA allocs 0 0
DMA32 allocs 31409797 28837521
Normal allocs 46611853 49231282
Movable allocs 0 0
Direct pages scanned 0 0
Kswapd pages scanned 40845270 40869088
Kswapd pages reclaimed 40830976 40855294
Direct pages reclaimed 0 0
Kswapd efficiency 99% 99%
Kswapd velocity 11386.711 11369.769
Direct efficiency 100% 100%
Direct velocity 0.000 0.000
Percentage direct scans 0% 0%
Page writes by reclaim 2855 1029
Page writes file 0 0
Page writes anon 2855 1029
Page reclaim immediate 771 1628
Sector Reads 293312636 293536360
Sector Writes 18213568 18186480
Page rescued immediate 0 0
Slabs scanned 128257 132747
Direct inode steals 181 56
Kswapd inode steals 59 1131
It basically shows that kswapd was active at roughly the same rate in
both kernels. There was also comparable slab scanning activity and direct
reclaim was avoided in both cases. There appears to be a large difference
in numbers of inodes reclaimed but the workload has few active inodes and
is likely a timing artifact.
stutter
-------
stutter simulates a simple workload. One part uses a lot of anonymous
memory, a second measures mmap latency and a third copies a large file.
The primary metric is checking for mmap latency.
stutter
4.7.0-rc4 4.7.0-rc4
mmotm-20160623 nodelru-v8
Min mmap 16.6283 ( 0.00%) 13.4258 ( 19.26%)
1st-qrtle mmap 54.7570 ( 0.00%) 34.9121 ( 36.24%)
2nd-qrtle mmap 57.3163 ( 0.00%) 46.1147 ( 19.54%)
3rd-qrtle mmap 58.9976 ( 0.00%) 47.1882 ( 20.02%)
Max-90% mmap 59.7433 ( 0.00%) 47.4453 ( 20.58%)
Max-93% mmap 60.1298 ( 0.00%) 47.6037 ( 20.83%)
Max-95% mmap 73.4112 ( 0.00%) 82.8719 (-12.89%)
Max-99% mmap 92.8542 ( 0.00%) 88.8870 ( 4.27%)
Max mmap 1440.6569 ( 0.00%) 121.4201 ( 91.57%)
Mean mmap 59.3493 ( 0.00%) 42.2991 ( 28.73%)
Best99%Mean mmap 57.2121 ( 0.00%) 41.8207 ( 26.90%)
Best95%Mean mmap 55.9113 ( 0.00%) 39.9620 ( 28.53%)
Best90%Mean mmap 55.6199 ( 0.00%) 39.3124 ( 29.32%)
Best50%Mean mmap 53.2183 ( 0.00%) 33.1307 ( 37.75%)
Best10%Mean mmap 45.9842 ( 0.00%) 20.4040 ( 55.63%)
Best5%Mean mmap 43.2256 ( 0.00%) 17.9654 ( 58.44%)
Best1%Mean mmap 32.9388 ( 0.00%) 16.6875 ( 49.34%)
This shows a number of improvements with the worst-case outlier greatly
improved.
Some of the vmstats are interesting
4.7.0-rc4 4.7.0-rc4
mmotm-20160623nodelru-v8
Swap Ins 163 502
Swap Outs 0 0
DMA allocs 0 0
DMA32 allocs 618719206 1381662383
Normal allocs 891235743 564138421
Movable allocs 0 0
Allocation stalls 2603 1
Direct pages scanned 216787 2
Kswapd pages scanned 50719775 41778378
Kswapd pages reclaimed 41541765 41777639
Direct pages reclaimed 209159 0
Kswapd efficiency 81% 99%
Kswapd velocity 16859.554 14329.059
Direct efficiency 96% 0%
Direct velocity 72.061 0.001
Percentage direct scans 0% 0%
Page writes by reclaim 6215049 0
Page writes file 6215049 0
Page writes anon 0 0
Page reclaim immediate 70673 90
Sector Reads 81940800 81680456
Sector Writes 100158984 98816036
Page rescued immediate 0 0
Slabs scanned 1366954 22683
While this is not guaranteed in all cases, this particular test showed
a large reduction in direct reclaim activity. It's also worth noting
that no page writes were issued from reclaim context.
This series is not without its hazards. There are at least three areas
that I'm concerned with even though I could not reproduce any problems in
that area.
1. Reclaim/compaction is going to be affected because the amount of reclaim is
no longer targetted at a specific zone. Compaction works on a per-zone basis
so there is no guarantee that reclaiming a few THP's worth page pages will
have a positive impact on compaction success rates.
2. The Slab/LRU reclaim ratio is affected because the frequency the shrinkers
are called is now different. This may or may not be a problem but if it
is, it'll be because shrinkers are not called enough and some balancing
is required.
3. The anon/file reclaim ratio may be affected. Pages about to be dirtied are
distributed between zones and the fair zone allocation policy used to do
something very similar for anon. The distribution is now different but not
necessarily in any way that matters but it's still worth bearing in mind.
VM statistic counters for reclaim decisions are zone-based. If the kernel
is to reclaim on a per-node basis then we need to track per-node
statistics but there is no infrastructure for that. The most notable
change is that the old node_page_state is renamed to
sum_zone_node_page_state. The new node_page_state takes a pglist_data and
uses per-node stats but none exist yet. There is some renaming such as
vm_stat to vm_zone_stat and the addition of vm_node_stat and the renaming
of mod_state to mod_zone_state. Otherwise, this is mostly a mechanical
patch with no functional change. There is a lot of similarity between the
node and zone helpers which is unfortunate but there was no obvious way of
reusing the code and maintaining type safety.
Link: http://lkml.kernel.org/r/1467970510-21195-2-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@surriel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
||
|
Kirill A. Shutemov
|
65c453778a |
mm, rmap: account shmem thp pages
Let's add ShmemHugePages and ShmemPmdMapped fields into meminfo and smaps. It indicates how many times we allocate and map shmem THP. NR_ANON_TRANSPARENT_HUGEPAGES is renamed to NR_ANON_THPS. Link: http://lkml.kernel.org/r/1466021202-61880-27-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
||
|
Minchan Kim
|
91537fee00 |
mm: add NR_ZSMALLOC to vmstat
zram is very popular for some of the embedded world (e.g., TV, mobile phones). On those system, zsmalloc's consumed memory size is never trivial (one of example from real product system, total memory: 800M, zsmalloc consumed: 150M), so we have used this out of tree patch to monitor system memory behavior via /proc/vmstat. With zsmalloc in vmstat, it helps in tracking down system behavior due to memory usage. [minchan@kernel.org: zsmalloc: follow up zsmalloc vmstat] Link: http://lkml.kernel.org/r/20160607091737.GC23435@bbox [akpm@linux-foundation.org: fix build with CONFIG_ZSMALLOC=m] Link: http://lkml.kernel.org/r/1464919731-13255-1-git-send-email-minchan@kernel.org Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Sangseok Lee <sangseok.lee@lge.com> Cc: Chanho Min <chanho.min@lge.com> Cc: Chan Gyun Jeong <chan.jeong@lge.com> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Vladimir Davydov
|
798fd75695 |
mm: zap ZONE_OOM_LOCKED
Not used since oom_lock was instroduced. Link: http://lkml.kernel.org/r/1464358093-22663-1-git-send-email-vdavydov@virtuozzo.com Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Laura Abbott
|
7c15d9bb82 |
mm: Add is_migrate_cma_page
Code such as hardened user copy[1] needs a way to tell if a page is CMA or not. Add is_migrate_cma_page in a similar way to is_migrate_isolate_page. [1]http://article.gmane.org/gmane.linux.kernel.mm/155238 Signed-off-by: Laura Abbott <labbott@redhat.com> Signed-off-by: Kees Cook <keescook@chromium.org> |
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|
Weijie Yang
|
0c9ad804f1 |
mm fix commmets: if SPARSEMEM, pgdata doesn't have page_ext
If SPARSEMEM, use page_ext in mem_section if !SPARSEMEM, use page_ext in pgdata Signed-off-by: Weijie Yang <weijie.yang@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Michal Hocko
|
86a294a81f |
mm, oom, compaction: prevent from should_compact_retry looping for ever for costly orders
"mm: consider compaction feedback also for costly allocation" has
removed the upper bound for the reclaim/compaction retries based on the
number of reclaimed pages for costly orders. While this is desirable
the patch did miss a mis interaction between reclaim, compaction and the
retry logic. The direct reclaim tries to get zones over min watermark
while compaction backs off and returns COMPACT_SKIPPED when all zones
are below low watermark + 1<<order gap. If we are getting really close
to OOM then __compaction_suitable can keep returning COMPACT_SKIPPED a
high order request (e.g. hugetlb order-9) while the reclaim is not able
to release enough pages to get us over low watermark. The reclaim is
still able to make some progress (usually trashing over few remaining
pages) so we are not able to break out from the loop.
I have seen this happening with the same test described in "mm: consider
compaction feedback also for costly allocation" on a swapless system.
The original problem got resolved by "vmscan: consider classzone_idx in
compaction_ready" but it shows how things might go wrong when we
approach the oom event horizont.
The reason why compaction requires being over low rather than min
watermark is not clear to me. This check was there essentially since
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Mel Gorman
|
0b423ca22f |
mm, page_alloc: inline pageblock lookup in page free fast paths
The function call overhead of get_pfnblock_flags_mask() is measurable in the page free paths. This patch uses an inlined version that is faster. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Mel Gorman
|
c33d6c06f6 |
mm, page_alloc: avoid looking up the first zone in a zonelist twice
The allocator fast path looks up the first usable zone in a zonelist and
then get_page_from_freelist does the same job in the zonelist iterator.
This patch preserves the necessary information.
4.6.0-rc2 4.6.0-rc2
fastmark-v1r20 initonce-v1r20
Min alloc-odr0-1 364.00 ( 0.00%) 359.00 ( 1.37%)
Min alloc-odr0-2 262.00 ( 0.00%) 260.00 ( 0.76%)
Min alloc-odr0-4 214.00 ( 0.00%) 214.00 ( 0.00%)
Min alloc-odr0-8 186.00 ( 0.00%) 186.00 ( 0.00%)
Min alloc-odr0-16 173.00 ( 0.00%) 173.00 ( 0.00%)
Min alloc-odr0-32 165.00 ( 0.00%) 165.00 ( 0.00%)
Min alloc-odr0-64 161.00 ( 0.00%) 162.00 ( -0.62%)
Min alloc-odr0-128 159.00 ( 0.00%) 161.00 ( -1.26%)
Min alloc-odr0-256 168.00 ( 0.00%) 170.00 ( -1.19%)
Min alloc-odr0-512 180.00 ( 0.00%) 181.00 ( -0.56%)
Min alloc-odr0-1024 190.00 ( 0.00%) 190.00 ( 0.00%)
Min alloc-odr0-2048 196.00 ( 0.00%) 196.00 ( 0.00%)
Min alloc-odr0-4096 202.00 ( 0.00%) 202.00 ( 0.00%)
Min alloc-odr0-8192 206.00 ( 0.00%) 205.00 ( 0.49%)
Min alloc-odr0-16384 206.00 ( 0.00%) 205.00 ( 0.49%)
The benefit is negligible and the results are within the noise but each
cycle counts.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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|
Mel Gorman
|
c603844bdc |
mm, page_alloc: convert alloc_flags to unsigned
alloc_flags is a bitmask of flags but it is signed which does not necessarily generate the best code depending on the compiler. Even without an impact, it makes more sense that this be unsigned. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Mel Gorman
|
682a3385e7 |
mm, page_alloc: inline the fast path of the zonelist iterator
The page allocator iterates through a zonelist for zones that match the
addressing limitations and nodemask of the caller but many allocations
will not be restricted. Despite this, there is always functional call
overhead which builds up.
This patch inlines the optimistic basic case and only calls the iterator
function for the complex case. A hindrance was the fact that
cpuset_current_mems_allowed is used in the fastpath as the allowed
nodemask even though all nodes are allowed on most systems. The patch
handles this by only considering cpuset_current_mems_allowed if a cpuset
exists. As well as being faster in the fast-path, this removes some
junk in the slowpath.
The performance difference on a page allocator microbenchmark is;
4.6.0-rc2 4.6.0-rc2
statinline-v1r20 optiter-v1r20
Min alloc-odr0-1 412.00 ( 0.00%) 382.00 ( 7.28%)
Min alloc-odr0-2 301.00 ( 0.00%) 282.00 ( 6.31%)
Min alloc-odr0-4 247.00 ( 0.00%) 233.00 ( 5.67%)
Min alloc-odr0-8 215.00 ( 0.00%) 203.00 ( 5.58%)
Min alloc-odr0-16 199.00 ( 0.00%) 188.00 ( 5.53%)
Min alloc-odr0-32 191.00 ( 0.00%) 182.00 ( 4.71%)
Min alloc-odr0-64 187.00 ( 0.00%) 177.00 ( 5.35%)
Min alloc-odr0-128 185.00 ( 0.00%) 175.00 ( 5.41%)
Min alloc-odr0-256 193.00 ( 0.00%) 184.00 ( 4.66%)
Min alloc-odr0-512 207.00 ( 0.00%) 197.00 ( 4.83%)
Min alloc-odr0-1024 213.00 ( 0.00%) 203.00 ( 4.69%)
Min alloc-odr0-2048 220.00 ( 0.00%) 209.00 ( 5.00%)
Min alloc-odr0-4096 226.00 ( 0.00%) 214.00 ( 5.31%)
Min alloc-odr0-8192 229.00 ( 0.00%) 218.00 ( 4.80%)
Min alloc-odr0-16384 229.00 ( 0.00%) 219.00 ( 4.37%)
perf indicated that next_zones_zonelist disappeared in the profile and
__next_zones_zonelist did not appear. This is expected as the
micro-benchmark would hit the inlined fast-path every time.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
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|
Chanho Min
|
29f9cb53d2 |
mm/highmem: simplify is_highmem()
is_highmem() can be simplified by use of is_highmem_idx(). This patch removes redundant code and will make it easier to maintain if the zone policy is changed or a new zone is added. (akpm: saves me 25 bytes of text per is_highmem() callsite) Signed-off-by: Chanho Min <chanho.min@lge.com> Reviewed-by: Dan Williams <dan.j.williams@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Johannes Weiner
|
795ae7a0de |
mm: scale kswapd watermarks in proportion to memory
In machines with 140G of memory and enterprise flash storage, we have seen read and write bursts routinely exceed the kswapd watermarks and cause thundering herds in direct reclaim. Unfortunately, the only way to tune kswapd aggressiveness is through adjusting min_free_kbytes - the system's emergency reserves - which is entirely unrelated to the system's latency requirements. In order to get kswapd to maintain a 250M buffer of free memory, the emergency reserves need to be set to 1G. That is a lot of memory wasted for no good reason. On the other hand, it's reasonable to assume that allocation bursts and overall allocation concurrency scale with memory capacity, so it makes sense to make kswapd aggressiveness a function of that as well. Change the kswapd watermark scale factor from the currently fixed 25% of the tunable emergency reserve to a tunable 0.1% of memory. Beyond 1G of memory, this will produce bigger watermark steps than the current formula in default settings. Ensure that the new formula never chooses steps smaller than that, i.e. 25% of the emergency reserve. On a 140G machine, this raises the default watermark steps - the distance between min and low, and low and high - from 16M to 143M. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Vlastimil Babka
|
698b1b3064 |
mm, compaction: introduce kcompactd
Memory compaction can be currently performed in several contexts: - kswapd balancing a zone after a high-order allocation failure - direct compaction to satisfy a high-order allocation, including THP page fault attemps - khugepaged trying to collapse a hugepage - manually from /proc The purpose of compaction is two-fold. The obvious purpose is to satisfy a (pending or future) high-order allocation, and is easy to evaluate. The other purpose is to keep overal memory fragmentation low and help the anti-fragmentation mechanism. The success wrt the latter purpose is more The current situation wrt the purposes has a few drawbacks: - compaction is invoked only when a high-order page or hugepage is not available (or manually). This might be too late for the purposes of keeping memory fragmentation low. - direct compaction increases latency of allocations. Again, it would be better if compaction was performed asynchronously to keep fragmentation low, before the allocation itself comes. - (a special case of the previous) the cost of compaction during THP page faults can easily offset the benefits of THP. - kswapd compaction appears to be complex, fragile and not working in some scenarios. It could also end up compacting for a high-order allocation request when it should be reclaiming memory for a later order-0 request. To improve the situation, we should be able to benefit from an equivalent of kswapd, but for compaction - i.e. a background thread which responds to fragmentation and the need for high-order allocations (including hugepages) somewhat proactively. One possibility is to extend the responsibilities of kswapd, which could however complicate its design too much. It should be better to let kswapd handle reclaim, as order-0 allocations are often more critical than high-order ones. Another possibility is to extend khugepaged, but this kthread is a single instance and tied to THP configs. This patch goes with the option of a new set of per-node kthreads called kcompactd, and lays the foundations, without introducing any new tunables. The lifecycle mimics kswapd kthreads, including the memory hotplug hooks. For compaction, kcompactd uses the standard compaction_suitable() and ompact_finished() criteria and the deferred compaction functionality. Unlike direct compaction, it uses only sync compaction, as there's no allocation latency to minimize. This patch doesn't yet add a call to wakeup_kcompactd. The kswapd compact/reclaim loop for high-order pages will be replaced by waking up kcompactd in the next patch with the description of what's wrong with the old approach. Waking up of the kcompactd threads is also tied to kswapd activity and follows these rules: - we don't want to affect any fastpaths, so wake up kcompactd only from the slowpath, as it's done for kswapd - if kswapd is doing reclaim, it's more important than compaction, so don't invoke kcompactd until kswapd goes to sleep - the target order used for kswapd is passed to kcompactd Future possible future uses for kcompactd include the ability to wake up kcompactd on demand in special situations, such as when hugepages are not available (currently not done due to __GFP_NO_KSWAPD) or when a fragmentation event (i.e. __rmqueue_fallback()) occurs. It's also possible to perform periodic compaction with kcompactd. [arnd@arndb.de: fix build errors with kcompactd] [paul.gortmaker@windriver.com: don't use modular references for non modular code] Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: David Rientjes <rientjes@google.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Joonsoo Kim
|
7cf91a98e6 |
mm/compaction: speed up pageblock_pfn_to_page() when zone is contiguous
There is a performance drop report due to hugepage allocation and in there half of cpu time are spent on pageblock_pfn_to_page() in compaction [1]. In that workload, compaction is triggered to make hugepage but most of pageblocks are un-available for compaction due to pageblock type and skip bit so compaction usually fails. Most costly operations in this case is to find valid pageblock while scanning whole zone range. To check if pageblock is valid to compact, valid pfn within pageblock is required and we can obtain it by calling pageblock_pfn_to_page(). This function checks whether pageblock is in a single zone and return valid pfn if possible. Problem is that we need to check it every time before scanning pageblock even if we re-visit it and this turns out to be very expensive in this workload. Although we have no way to skip this pageblock check in the system where hole exists at arbitrary position, we can use cached value for zone continuity and just do pfn_to_page() in the system where hole doesn't exist. This optimization considerably speeds up in above workload. Before vs After Max: 1096 MB/s vs 1325 MB/s Min: 635 MB/s 1015 MB/s Avg: 899 MB/s 1194 MB/s Avg is improved by roughly 30% [2]. [1]: http://www.spinics.net/lists/linux-mm/msg97378.html [2]: https://lkml.org/lkml/2015/12/9/23 [akpm@linux-foundation.org: don't forget to restore zone->contiguous on error path, per Vlastimil] Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Reported-by: Aaron Lu <aaron.lu@intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Tested-by: Aaron Lu <aaron.lu@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Johannes Weiner
|
23047a96d7 |
mm: workingset: per-cgroup cache thrash detection
Cache thrash detection (see
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|
Vlastimil Babka
|
60f30350fd |
mm, page_owner: print migratetype of page and pageblock, symbolic flags
The information in /sys/kernel/debug/page_owner includes the migratetype of the pageblock the page belongs to. This is also checked against the page's migratetype (as declared by gfp_flags during its allocation), and the page is reported as Fallback if its migratetype differs from the pageblock's one. t This is somewhat misleading because in fact fallback allocation is not the only reason why these two can differ. It also doesn't direcly provide the page's migratetype, although it's possible to derive that from the gfp_flags. It's arguably better to print both page and pageblock's migratetype and leave the interpretation to the consumer than to suggest fallback allocation as the only possible reason. While at it, we can print the migratetypes as string the same way as /proc/pagetypeinfo does, as some of the numeric values depend on kernel configuration. For that, this patch moves the migratetype_names array from #ifdef CONFIG_PROC_FS part of mm/vmstat.c to mm/page_alloc.c and exports it. With the new format strings for flags, we can now also provide symbolic page and gfp flags in the /sys/kernel/debug/page_owner file. This replaces the positional printing of page flags as single letters, which might have looked nicer, but was limited to a subset of flags, and required the user to remember the letters. Example page_owner entry after the patch: Page allocated via order 0, mask 0x24213ca(GFP_HIGHUSER_MOVABLE|__GFP_COLD|__GFP_NOWARN|__GFP_NORETRY) PFN 520 type Movable Block 1 type Movable Flags 0xfffff8001006c(referenced|uptodate|lru|active|mappedtodisk) [<ffffffff811682c4>] __alloc_pages_nodemask+0x134/0x230 [<ffffffff811b4058>] alloc_pages_current+0x88/0x120 [<ffffffff8115e386>] __page_cache_alloc+0xe6/0x120 [<ffffffff8116ba6c>] __do_page_cache_readahead+0xdc/0x240 [<ffffffff8116bd05>] ondemand_readahead+0x135/0x260 [<ffffffff8116bfb1>] page_cache_sync_readahead+0x31/0x50 [<ffffffff81160523>] generic_file_read_iter+0x453/0x760 [<ffffffff811e0d57>] __vfs_read+0xa7/0xd0 Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Sasha Levin <sasha.levin@oracle.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: 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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|
Kirill A. Shutemov
|
a3d0a91850 |
thp: make split_queue per-node
Andrea Arcangeli suggested to make split queue per-node to improve scalability. Let's do it. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Suggested-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Jerome Marchand <jmarchan@redhat.com> Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Johannes Weiner
|
a8d0143730 |
mm: page_alloc: generalize the dirty balance reserve
The dirty balance reserve that dirty throttling has to consider is merely memory not available to userspace allocations. There is nothing writeback-specific about it. Generalize the name so that it's reusable outside of that context. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Yaowei Bai
|
5b80287a65 |
mm/mmzone.c: memmap_valid_within() can be boolean
Make memmap_valid_within return bool due to this particular function only using either one or zero as its return value. No functional change. Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Yaowei Bai
|
c00eb15a89 |
mm/zonelist: enumerate zonelists array index
Hardcoding index to zonelists array in gfp_zonelist() is not a good idea, let's enumerate it to improve readability. No functional change. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix CONFIG_NUMA=n build] [n-horiguchi@ah.jp.nec.com: fix warning in comparing enumerator] Signed-off-by: Yaowei Bai <baiyaowei@cmss.chinamobile.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Yaowei Bai
|
06640290bf |
include/linux/mmzone.h: remove unused is_unevictable_lru()
Since commit
|
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|
Andrew Morton
|
8990332760 |
include/linux/mmzone.h: reflow comment
Someone has an 86 column display. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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|
Mel Gorman
|
0aaa29a56e |
mm, page_alloc: reserve pageblocks for high-order atomic allocations on demand
High-order watermark checking exists for two reasons -- kswapd high-order awareness and protection for high-order atomic requests. Historically the kernel depended on MIGRATE_RESERVE to preserve min_free_kbytes as high-order free pages for as long as possible. This patch introduces MIGRATE_HIGHATOMIC that reserves pageblocks for high-order atomic allocations on demand and avoids using those blocks for order-0 allocations. This is more flexible and reliable than MIGRATE_RESERVE was. A MIGRATE_HIGHORDER pageblock is created when an atomic high-order allocation request steals a pageblock but limits the total number to 1% of the zone. Callers that speculatively abuse atomic allocations for long-lived high-order allocations to access the reserve will quickly fail. Note that SLUB is currently not such an abuser as it reclaims at least once. It is possible that the pageblock stolen has few suitable high-order pages and will need to steal again in the near future but there would need to be strong justification to search all pageblocks for an ideal candidate. The pageblocks are unreserved if an allocation fails after a direct reclaim attempt. The watermark checks account for the reserved pageblocks when the allocation request is not a high-order atomic allocation. The reserved pageblocks can not be used for order-0 allocations. This may allow temporary wastage until a failed reclaim reassigns the pageblock. This is deliberate as the intent of the reservation is to satisfy a limited number of atomic high-order short-lived requests if the system requires them. The stutter benchmark was used to evaluate this but while it was running there was a systemtap script that randomly allocated between 1 high-order page and 12.5% of memory's worth of order-3 pages using GFP_ATOMIC. This is much larger than the potential reserve and it does not attempt to be realistic. It is intended to stress random high-order allocations from an unknown source, show that there is a reduction in failures without introducing an anomaly where atomic allocations are more reliable than regular allocations. The amount of memory reserved varied throughout the workload as reserves were created and reclaimed under memory pressure. The allocation failures once the workload warmed up were as follows; 4.2-rc5-vanilla 70% 4.2-rc5-atomic-reserve 56% The failure rate was also measured while building multiple kernels. The failure rate was 14% but is 6% with this patch applied. Overall, this is a small reduction but the reserves are small relative to the number of allocation requests. In early versions of the patch, the failure rate reduced by a much larger amount but that required much larger reserves and perversely made atomic allocations seem more reliable than regular allocations. [yalin.wang2010@gmail.com: fix redundant check and a memory leak] Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Vitaly Wool <vitalywool@gmail.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: yalin wang <yalin.wang2010@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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Mel Gorman
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974a786e63 |
mm, page_alloc: remove MIGRATE_RESERVE
MIGRATE_RESERVE preserves an old property of the buddy allocator that existed prior to fragmentation avoidance -- min_free_kbytes worth of pages tended to remain contiguous until the only alternative was to fail the allocation. At the time it was discovered that high-order atomic allocations relied on this property so MIGRATE_RESERVE was introduced. A later patch will introduce an alternative MIGRATE_HIGHATOMIC so this patch deletes MIGRATE_RESERVE and supporting code so it'll be easier to review. Note that this patch in isolation may look like a false regression if someone was bisecting high-order atomic allocation failures. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vitaly Wool <vitalywool@gmail.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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Mel Gorman
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f77cf4e4cc |
mm, page_alloc: delete the zonelist_cache
The zonelist cache (zlc) was introduced to skip over zones that were
recently known to be full. This avoided expensive operations such as the
cpuset checks, watermark calculations and zone_reclaim. The situation
today is different and the complexity of zlc is harder to justify.
1) The cpuset checks are no-ops unless a cpuset is active and in general
are a lot cheaper.
2) zone_reclaim is now disabled by default and I suspect that was a large
source of the cost that zlc wanted to avoid. When it is enabled, it's
known to be a major source of stalling when nodes fill up and it's
unwise to hit every other user with the overhead.
3) Watermark checks are expensive to calculate for high-order
allocation requests. Later patches in this series will reduce the cost
of the watermark checking.
4) The most important issue is that in the current implementation it
is possible for a failed THP allocation to mark a zone full for order-0
allocations and cause a fallback to remote nodes.
The last issue could be addressed with additional complexity but as the
benefit of zlc is questionable, it is better to remove it. If stalls due
to zone_reclaim are ever reported then an alternative would be to
introduce deferring logic based on a timeout inside zone_reclaim itself
and leave the page allocator fast paths alone.
The impact on page-allocator microbenchmarks is negligible as they don't
hit the paths where the zlc comes into play. Most page-reclaim related
workloads showed no noticeable difference as a result of the removal.
The impact was noticeable in a workload called "stutter". One part uses a
lot of anonymous memory, a second measures mmap latency and a third copies
a large file. In an ideal world the latency application would not notice
the mmap latency. On a 2-node machine the results of this patch are
stutter
4.3.0-rc1 4.3.0-rc1
baseline nozlc-v4
Min mmap 20.9243 ( 0.00%) 20.7716 ( 0.73%)
1st-qrtle mmap 22.0612 ( 0.00%) 22.0680 ( -0.03%)
2nd-qrtle mmap 22.3291 ( 0.00%) 22.3809 ( -0.23%)
3rd-qrtle mmap 25.2244 ( 0.00%) 25.2396 ( -0.06%)
Max-90% mmap 48.0995 ( 0.00%) 28.3713 ( 41.02%)
Max-93% mmap 52.5557 ( 0.00%) 36.0170 ( 31.47%)
Max-95% mmap 55.8173 ( 0.00%) 47.3163 ( 15.23%)
Max-99% mmap 67.3781 ( 0.00%) 70.1140 ( -4.06%)
Max mmap 24447.6375 ( 0.00%) 12915.1356 ( 47.17%)
Mean mmap 33.7883 ( 0.00%) 27.7944 ( 17.74%)
Best99%Mean mmap 27.7825 ( 0.00%) 25.2767 ( 9.02%)
Best95%Mean mmap 26.3912 ( 0.00%) 23.7994 ( 9.82%)
Best90%Mean mmap 24.9886 ( 0.00%) 23.2251 ( 7.06%)
Best50%Mean mmap 22.0157 ( 0.00%) 22.0261 ( -0.05%)
Best10%Mean mmap 21.6705 ( 0.00%) 21.6083 ( 0.29%)
Best5%Mean mmap 21.5581 ( 0.00%) 21.4611 ( 0.45%)
Best1%Mean mmap 21.3079 ( 0.00%) 21.1631 ( 0.68%)
Note that the maximum stall latency went from 24 seconds to 12 which is
still bad but an improvement. The milage varies considerably 2-node
machine on an earlier test went from 494 seconds to 47 seconds and a
4-node machine that tested an earlier version of this patch went from a
worst case stall time of 6 seconds to 67ms. The nature of the benchmark
is inherently unpredictable as it is hammering the system and the milage
will vary between machines.
There is a secondary impact with potentially more direct reclaim because
zones are now being considered instead of being skipped by zlc. In this
particular test run it did not occur so will not be described. However,
in at least one test the following was observed
1. Direct reclaim rates were higher. This was likely due to direct reclaim
being entered instead of the zlc disabling a zone and busy looping.
Busy looping may have the effect of allowing kswapd to make more
progress and in some cases may be better overall. If this is found then
the correct action is to put direct reclaimers to sleep on a waitqueue
and allow kswapd make forward progress. Busy looping on the zlc is even
worse than when the allocator used to blindly call congestion_wait().
2. There was higher swap activity as direct reclaim was active.
3. Direct reclaim efficiency was lower. This is related to 1 as more
scanning activity also encountered more pages that could not be
immediately reclaimed
In that case, the direct page scan and reclaim rates are noticeable but
it is not considered a problem for a few reasons
1. The test is primarily concerned with latency. The mmap attempts are also
faulted which means there are THP allocation requests. The ZLC could
cause zones to be disabled causing the process to busy loop instead
of reclaiming. This looks like elevated direct reclaim activity but
it's the correct action to take based on what processes requested.
2. The test hammers reclaim and compaction heavily. The number of successful
THP faults is highly variable but affects the reclaim stats. It's not a
realistic or reasonable measure of page reclaim activity.
3. No other page-reclaim intensive workload that was tested showed a problem.
4. If a workload is identified that benefitted from the busy looping then it
should be fixed by having direct reclaimers sleep on a wait queue until
woken by kswapd instead of busy looping. We had this class of problem before
when congestion_waits() with a fixed timeout was a brain damaged decision
but happened to benefit some workloads.
If a workload is identified that relied on the zlc to busy loop then it
should be fixed correctly and have a direct reclaimer sleep on a waitqueue
until woken by kswapd.
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vitaly Wool <vitalywool@gmail.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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Mel Gorman
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016c13daa5 |
mm, page_alloc: use masks and shifts when converting GFP flags to migrate types
This patch redefines which GFP bits are used for specifying mobility and the order of the migrate types. Once redefined it's possible to convert GFP flags to a migrate type with a simple mask and shift. The only downside is that readers of OOM kill messages and allocation failures may have been used to the existing values but scripts/gfp-translate will help. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Vitaly Wool <vitalywool@gmail.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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Mel Gorman
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e2b19197ff |
mm, page_alloc: remove unnecessary parameter from zone_watermark_ok_safe
Overall, the intent of this series is to remove the zonelist cache which was introduced to avoid high overhead in the page allocator. Once this is done, it is necessary to reduce the cost of watermark checks. The series starts with minor micro-optimisations. Next it notes that GFP flags that affect watermark checks are abused. __GFP_WAIT historically identified callers that could not sleep and could access reserves. This was later abused to identify callers that simply prefer to avoid sleeping and have other options. A patch distinguishes between atomic callers, high-priority callers and those that simply wish to avoid sleep. The zonelist cache has been around for a long time but it is of dubious merit with a lot of complexity and some issues that are explained. The most important issue is that a failed THP allocation can cause a zone to be treated as "full". This potentially causes unnecessary stalls, reclaim activity or remote fallbacks. The issues could be fixed but it's not worth it. The series places a small number of other micro-optimisations on top before examining GFP flags watermarks. High-order watermarks enforcement can cause high-order allocations to fail even though pages are free. The watermark checks both protect high-order atomic allocations and make kswapd aware of high-order pages but there is a much better way that can be handled using migrate types. This series uses page grouping by mobility to reserve pageblocks for high-order allocations with the size of the reservation depending on demand. kswapd awareness is maintained by examining the free lists. By patch 12 in this series, there are no high-order watermark checks while preserving the properties that motivated the introduction of the watermark checks. This patch (of 10): No user of zone_watermark_ok_safe() specifies alloc_flags. This patch removes the unnecessary parameter. Signed-off-by: Mel Gorman <mgorman@techsingularity.net> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Michal Hocko <mhocko@suse.com> Reviewed-by: Christoph Lameter <cl@linux.com> Acked-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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Yaowei Bai
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b171e40930 |
mm/page_alloc: remove unused parameter in init_currently_empty_zone()
Commit
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