mm: vmscan: scan until it finds eligible pages
Although there are a ton of free swap and anonymous LRU page in elgible
zones, OOM happened.
balloon invoked oom-killer: gfp_mask=0x17080c0(GFP_KERNEL_ACCOUNT|__GFP_ZERO|__GFP_NOTRACK), nodemask=(null), order=0, oom_score_adj=0
CPU: 7 PID: 1138 Comm: balloon Not tainted 4.11.0-rc6-mm1-zram-00289-ge228d67e9677-dirty #17
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
Call Trace:
oom_kill_process+0x21d/0x3f0
out_of_memory+0xd8/0x390
__alloc_pages_slowpath+0xbc1/0xc50
__alloc_pages_nodemask+0x1a5/0x1c0
pte_alloc_one+0x20/0x50
__pte_alloc+0x1e/0x110
__handle_mm_fault+0x919/0x960
handle_mm_fault+0x77/0x120
__do_page_fault+0x27a/0x550
trace_do_page_fault+0x43/0x150
do_async_page_fault+0x2c/0x90
async_page_fault+0x28/0x30
Mem-Info:
active_anon:424716 inactive_anon:65314 isolated_anon:0
active_file:52 inactive_file:46 isolated_file:0
unevictable:0 dirty:27 writeback:0 unstable:0
slab_reclaimable:3967 slab_unreclaimable:4125
mapped:133 shmem:43 pagetables:1674 bounce:0
free:4637 free_pcp:225 free_cma:0
Node 0 active_anon:1698864kB inactive_anon:261256kB active_file:208kB inactive_file:184kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:532kB dirty:108kB writeback:0kB shmem:172kB writeback_tmp:0kB unstable:0kB all_unreclaimable? no
DMA free:7316kB min:32kB low:44kB high:56kB active_anon:8064kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15992kB managed:15908kB mlocked:0kB slab_reclaimable:464kB slab_unreclaimable:40kB kernel_stack:0kB pagetables:24kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
lowmem_reserve[]: 0 992 992 1952
DMA32 free:9088kB min:2048kB low:3064kB high:4080kB active_anon:952176kB inactive_anon:0kB active_file:36kB inactive_file:0kB unevictable:0kB writepending:88kB present:1032192kB managed:1019388kB mlocked:0kB slab_reclaimable:13532kB slab_unreclaimable:16460kB kernel_stack:3552kB pagetables:6672kB bounce:0kB free_pcp:56kB local_pcp:24kB free_cma:0kB
lowmem_reserve[]: 0 0 0 959
Movable free:3644kB min:1980kB low:2960kB high:3940kB active_anon:738560kB inactive_anon:261340kB active_file:188kB inactive_file:640kB unevictable:0kB writepending:20kB present:1048444kB managed:1010816kB mlocked:0kB slab_reclaimable:0kB slab_unreclaimable:0kB kernel_stack:0kB pagetables:0kB bounce:0kB free_pcp:832kB local_pcp:60kB free_cma:0kB
lowmem_reserve[]: 0 0 0 0
DMA: 1*4kB (E) 0*8kB 18*16kB (E) 10*32kB (E) 10*64kB (E) 9*128kB (ME) 8*256kB (E) 2*512kB (E) 2*1024kB (E) 0*2048kB 0*4096kB = 7524kB
DMA32: 417*4kB (UMEH) 181*8kB (UMEH) 68*16kB (UMEH) 48*32kB (UMEH) 14*64kB (MH) 3*128kB (M) 1*256kB (H) 1*512kB (M) 2*1024kB (M) 0*2048kB 0*4096kB = 9836kB
Movable: 1*4kB (M) 1*8kB (M) 1*16kB (M) 1*32kB (M) 0*64kB 1*128kB (M) 2*256kB (M) 4*512kB (M) 1*1024kB (M) 0*2048kB 0*4096kB = 3772kB
378 total pagecache pages
17 pages in swap cache
Swap cache stats: add 17325, delete 17302, find 0/27
Free swap = 978940kB
Total swap = 1048572kB
524157 pages RAM
0 pages HighMem/MovableOnly
12629 pages reserved
0 pages cma reserved
0 pages hwpoisoned
[ pid ] uid tgid total_vm rss nr_ptes nr_pmds swapents oom_score_adj name
[ 433] 0 433 4904 5 14 3 82 0 upstart-udev-br
[ 438] 0 438 12371 5 27 3 191 -1000 systemd-udevd
With investigation, skipping page of isolate_lru_pages makes reclaim
void because it returns zero nr_taken easily so LRU shrinking is
effectively nothing and just increases priority aggressively. Finally,
OOM happens.
The problem is that get_scan_count determines nr_to_scan with eligible
zones so although priority drops to zero, it couldn't reclaim any pages
if the LRU contains mostly ineligible pages.
get_scan_count:
size = lruvec_lru_size(lruvec, lru, sc->reclaim_idx);
size = size >> sc->priority;
Assumes sc->priority is 0 and LRU list is as follows.
N-N-N-N-H-H-H-H-H-H-H-H-H-H-H-H-H-H-H-H
(Ie, small eligible pages are in the head of LRU but others are
almost ineligible pages)
In that case, size becomes 4 so VM want to scan 4 pages but 4 pages from
tail of the LRU are not eligible pages. If get_scan_count counts
skipped pages, it doesn't reclaim any pages remained after scanning 4
pages so it ends up OOM happening.
This patch makes isolate_lru_pages try to scan pages until it encounters
eligible zones's pages.
[akpm@linux-foundation.org: clean up mind-bending `for' statement. Tweak comment text]
Fixes: 3db65812d6 ("Revert "mm, vmscan: account for skipped pages as a partial scan"")
Link: http://lkml.kernel.org/r/1494457232-27401-1-git-send-email-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Minchan Kim
Linus Torvalds
parent
338a16ba15
commit
791b48b642
21
mm/vmscan.c
21
mm/vmscan.c
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@ -1449,7 +1449,7 @@ static __always_inline void update_lru_sizes(struct lruvec *lruvec,
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*
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* Appropriate locks must be held before calling this function.
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*
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* @nr_to_scan: The number of pages to look through on the list.
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* @nr_to_scan: The number of eligible pages to look through on the list.
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* @lruvec: The LRU vector to pull pages from.
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* @dst: The temp list to put pages on to.
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* @nr_scanned: The number of pages that were scanned.
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@ -1469,11 +1469,13 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
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unsigned long nr_zone_taken[MAX_NR_ZONES] = { 0 };
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unsigned long nr_skipped[MAX_NR_ZONES] = { 0, };
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unsigned long skipped = 0;
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unsigned long scan, nr_pages;
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unsigned long scan, total_scan, nr_pages;
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LIST_HEAD(pages_skipped);
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for (scan = 0; scan < nr_to_scan && nr_taken < nr_to_scan &&
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!list_empty(src); scan++) {
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scan = 0;
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for (total_scan = 0;
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scan < nr_to_scan && nr_taken < nr_to_scan && !list_empty(src);
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total_scan++) {
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struct page *page;
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page = lru_to_page(src);
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@ -1487,6 +1489,13 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
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continue;
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}
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/*
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* Do not count skipped pages because that makes the function
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* return with no isolated pages if the LRU mostly contains
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* ineligible pages. This causes the VM to not reclaim any
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* pages, triggering a premature OOM.
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*/
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scan++;
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switch (__isolate_lru_page(page, mode)) {
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case 0:
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nr_pages = hpage_nr_pages(page);
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@ -1524,9 +1533,9 @@ static unsigned long isolate_lru_pages(unsigned long nr_to_scan,
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skipped += nr_skipped[zid];
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}
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}
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*nr_scanned = scan;
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*nr_scanned = total_scan;
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trace_mm_vmscan_lru_isolate(sc->reclaim_idx, sc->order, nr_to_scan,
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scan, skipped, nr_taken, mode, lru);
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total_scan, skipped, nr_taken, mode, lru);
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update_lru_sizes(lruvec, lru, nr_zone_taken);
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return nr_taken;
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}
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