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Message-ID: <ca3da8b8-1bb5-c302-b190-fa6cebab58ca@I-love.SAKURA.ne.jp>
Date: Thu, 26 Jul 2018 20:06:24 +0900
From: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
To: Michal Hocko <mhocko@...e.com>, Roman Gushchin <guro@...com>,
Johannes Weiner <hannes@...xchg.org>,
Vladimir Davydov <vdavydov.dev@...il.com>,
David Rientjes <rientjes@...gle.com>,
Tejun Heo <tj@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
linux-mm <linux-mm@...ck.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: [PATCH] mm,page_alloc: PF_WQ_WORKER threads must sleep at
should_reclaim_retry().
Before applying "an OOM lockup mitigation patch", I want to apply this
"another OOM lockup avoidance" patch.
Complete log is at http://I-love.SAKURA.ne.jp/tmp/serial-20180726.txt.xz
(which was captured with
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -1071,6 +1071,12 @@ bool out_of_memory(struct oom_control *oc)
{
unsigned long freed = 0;
bool delay = false; /* if set, delay next allocation attempt */
+ static unsigned long last_warned;
+ if (!last_warned || time_after(jiffies, last_warned + 10 * HZ)) {
+ pr_warn("%s(%d) gfp_mask=%#x(%pGg), order=%d\n", current->comm,
+ current->pid, oc->gfp_mask, &oc->gfp_mask, oc->order);
+ last_warned = jiffies;
+ }
oc->constraint = CONSTRAINT_NONE;
if (oom_killer_disabled)
in order to demonstrate that the GFP_NOIO allocation from disk_events_workfn() is
calling out_of_memory() rather than by error failing to give up direct reclaim).
[ 258.619119] kworker/0:0(5) gfp_mask=0x600000(GFP_NOIO), order=0
[ 268.622732] kworker/0:0(5) gfp_mask=0x600000(GFP_NOIO), order=0
[ 278.635344] kworker/0:0(5) gfp_mask=0x600000(GFP_NOIO), order=0
[ 288.639360] kworker/0:0(5) gfp_mask=0x600000(GFP_NOIO), order=0
[ 298.642715] kworker/0:0(5) gfp_mask=0x600000(GFP_NOIO), order=0
[ 308.527975] sysrq: SysRq : Show Memory
[ 308.529713] Mem-Info:
[ 308.530930] active_anon:855844 inactive_anon:2123 isolated_anon:0
[ 308.530930] active_file:7 inactive_file:12 isolated_file:0
[ 308.530930] unevictable:0 dirty:0 writeback:0 unstable:0
[ 308.530930] slab_reclaimable:3444 slab_unreclaimable:23008
[ 308.530930] mapped:1743 shmem:2272 pagetables:3991 bounce:0
[ 308.530930] free:21206 free_pcp:165 free_cma:0
[ 308.542309] Node 0 active_anon:3423376kB inactive_anon:8492kB active_file:28kB inactive_file:48kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:6972kB dirty:0kB writeback:0kB shmem:9088kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 3227648kB writeback_tmp:0kB unstable:0kB all_unreclaimable? yes
[ 308.550495] Node 0 DMA free:14712kB min:288kB low:360kB high:432kB active_anon:1128kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15960kB managed:15876kB mlocked:0kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 308.558420] lowmem_reserve[]: 0 2717 3607 3607
[ 308.560197] Node 0 DMA32 free:53860kB min:50684kB low:63352kB high:76020kB active_anon:2727108kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:3129152kB managed:2782536kB mlocked:0kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 308.568640] lowmem_reserve[]: 0 0 890 890
[ 308.570396] Node 0 Normal free:16252kB min:16608kB low:20760kB high:24912kB active_anon:694864kB inactive_anon:8492kB active_file:44kB inactive_file:0kB unevictable:0kB writepending:0kB present:1048576kB managed:911820kB mlocked:0kB kernel_stack:8080kB pagetables:15956kB bounce:0kB free_pcp:660kB local_pcp:660kB free_cma:0kB
[ 308.580075] lowmem_reserve[]: 0 0 0 0
[ 308.581827] Node 0 DMA: 0*4kB 1*8kB (M) 1*16kB (M) 1*32kB (U) 1*64kB (U) 2*128kB (UM) 2*256kB (UM) 1*512kB (M) 1*1024kB (U) 0*2048kB 3*4096kB (M) = 14712kB
[ 308.586271] Node 0 DMA32: 5*4kB (UM) 3*8kB (U) 5*16kB (U) 5*32kB (U) 5*64kB (U) 2*128kB (UM) 2*256kB (UM) 7*512kB (M) 4*1024kB (M) 2*2048kB (UM) 10*4096kB (UM) = 54108kB
[ 308.591900] Node 0 Normal: 13*4kB (UM) 5*8kB (UM) 2*16kB (U) 74*32kB (UME) 23*64kB (UME) 6*128kB (UME) 5*256kB (U) 2*512kB (UM) 9*1024kB (M) 0*2048kB 0*4096kB = 16252kB
[ 308.597637] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[ 308.600764] 2273 total pagecache pages
[ 308.602712] 0 pages in swap cache
[ 308.604532] Swap cache stats: add 0, delete 0, find 0/0
[ 308.606843] Free swap = 0kB
[ 308.608632] Total swap = 0kB
[ 308.610357] 1048422 pages RAM
[ 308.612153] 0 pages HighMem/MovableOnly
[ 308.614173] 120864 pages reserved
[ 308.615994] 0 pages cma reserved
[ 308.617811] 0 pages hwpoisoned
[ 308.527975] sysrq: SysRq : Show Memory
[ 308.529713] Mem-Info:
[ 308.530930] active_anon:855844 inactive_anon:2123 isolated_anon:0
[ 308.530930] active_file:7 inactive_file:12 isolated_file:0
[ 308.530930] unevictable:0 dirty:0 writeback:0 unstable:0
[ 308.530930] slab_reclaimable:3444 slab_unreclaimable:23008
[ 308.530930] mapped:1743 shmem:2272 pagetables:3991 bounce:0
[ 308.530930] free:21206 free_pcp:165 free_cma:0
[ 308.542309] Node 0 active_anon:3423376kB inactive_anon:8492kB active_file:28kB inactive_file:48kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:6972kB dirty:0kB writeback:0kB shmem:9088kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 3227648kB writeback_tmp:0kB unstable:0kB all_unreclaimable? yes
[ 308.550495] Node 0 DMA free:14712kB min:288kB low:360kB high:432kB active_anon:1128kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15960kB managed:15876kB mlocked:0kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 308.558420] lowmem_reserve[]: 0 2717 3607 3607
[ 308.560197] Node 0 DMA32 free:53860kB min:50684kB low:63352kB high:76020kB active_anon:2727108kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:3129152kB managed:2782536kB mlocked:0kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 308.568640] lowmem_reserve[]: 0 0 890 890
[ 308.570396] Node 0 Normal free:16252kB min:16608kB low:20760kB high:24912kB active_anon:694864kB inactive_anon:8492kB active_file:44kB inactive_file:0kB unevictable:0kB writepending:0kB present:1048576kB managed:911820kB mlocked:0kB kernel_stack:8080kB pagetables:15956kB bounce:0kB free_pcp:660kB local_pcp:660kB free_cma:0kB
[ 308.580075] lowmem_reserve[]: 0 0 0 0
[ 308.581827] Node 0 DMA: 0*4kB 1*8kB (M) 1*16kB (M) 1*32kB (U) 1*64kB (U) 2*128kB (UM) 2*256kB (UM) 1*512kB (M) 1*1024kB (U) 0*2048kB 3*4096kB (M) = 14712kB
[ 308.586271] Node 0 DMA32: 5*4kB (UM) 3*8kB (U) 5*16kB (U) 5*32kB (U) 5*64kB (U) 2*128kB (UM) 2*256kB (UM) 7*512kB (M) 4*1024kB (M) 2*2048kB (UM) 10*4096kB (UM) = 54108kB
[ 308.591900] Node 0 Normal: 13*4kB (UM) 5*8kB (UM) 2*16kB (U) 74*32kB (UME) 23*64kB (UME) 6*128kB (UME) 5*256kB (U) 2*512kB (UM) 9*1024kB (M) 0*2048kB 0*4096kB = 16252kB
[ 308.597637] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[ 308.600764] 2273 total pagecache pages
[ 308.602712] 0 pages in swap cache
[ 308.604532] Swap cache stats: add 0, delete 0, find 0/0
[ 308.606843] Free swap = 0kB
[ 308.608632] Total swap = 0kB
[ 308.610357] 1048422 pages RAM
[ 308.612153] 0 pages HighMem/MovableOnly
[ 308.614173] 120864 pages reserved
[ 308.615994] 0 pages cma reserved
[ 308.617811] 0 pages hwpoisoned
[ 310.383005] kworker/0:0 R running task 13504 5 2 0x80000000
[ 310.385328] Workqueue: events_freezable_power_ disk_events_workfn
[ 310.387578] Call Trace:
[ 310.475050] ? shrink_node+0xca/0x460
[ 310.476614] shrink_node+0xca/0x460
[ 310.478129] do_try_to_free_pages+0xcb/0x380
[ 310.479848] try_to_free_pages+0xbb/0xf0
[ 310.481481] __alloc_pages_slowpath+0x3c1/0xc50
[ 310.483332] __alloc_pages_nodemask+0x2a6/0x2c0
[ 310.485130] bio_copy_kern+0xcd/0x200
[ 310.486710] blk_rq_map_kern+0xb6/0x130
[ 310.488317] scsi_execute+0x64/0x250
[ 310.489859] sr_check_events+0x9a/0x2b0 [sr_mod]
[ 310.491669] ? __mutex_unlock_slowpath+0x46/0x2b0
[ 310.493581] cdrom_check_events+0xf/0x30 [cdrom]
[ 310.495435] sr_block_check_events+0x7c/0xb0 [sr_mod]
[ 310.497434] disk_check_events+0x5e/0x150
[ 310.499172] process_one_work+0x290/0x4a0
[ 310.500878] ? process_one_work+0x227/0x4a0
[ 310.502591] worker_thread+0x28/0x3d0
[ 310.504184] ? process_one_work+0x4a0/0x4a0
[ 310.505916] kthread+0x107/0x120
[ 310.507384] ? kthread_create_worker_on_cpu+0x70/0x70
[ 310.509333] ret_from_fork+0x24/0x30
[ 324.960731] Showing busy workqueues and worker pools:
[ 324.962577] workqueue events: flags=0x0
[ 324.964137] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=13/256
[ 324.966231] pending: vmw_fb_dirty_flush [vmwgfx], vmstat_shepherd, vmpressure_work_fn, free_work, mmdrop_async_fn, mmdrop_async_fn, mmdrop_async_fn, mmdrop_async_fn, e1000_watchdog [e1000], mmdrop_async_fn, mmdrop_async_fn, check_corruption, console_callback
[ 324.973425] workqueue events_freezable: flags=0x4
[ 324.975247] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 324.977393] pending: vmballoon_work [vmw_balloon]
[ 324.979310] workqueue events_power_efficient: flags=0x80
[ 324.981298] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=5/256
[ 324.983543] pending: gc_worker [nf_conntrack], fb_flashcursor, neigh_periodic_work, neigh_periodic_work, check_lifetime
[ 324.987240] workqueue events_freezable_power_: flags=0x84
[ 324.989292] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 324.991482] in-flight: 5:disk_events_workfn
[ 324.993371] workqueue mm_percpu_wq: flags=0x8
[ 324.995167] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256
[ 324.997363] pending: vmstat_update, drain_local_pages_wq BAR(498)
[ 324.999977] workqueue ipv6_addrconf: flags=0x40008
[ 325.001899] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1
[ 325.004092] pending: addrconf_verify_work
[ 325.005911] workqueue mpt_poll_0: flags=0x8
[ 325.007686] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 325.009914] pending: mpt_fault_reset_work [mptbase]
[ 325.012044] workqueue xfs-cil/sda1: flags=0xc
[ 325.013897] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 325.016190] pending: xlog_cil_push_work [xfs] BAR(2344)
[ 325.018354] workqueue xfs-reclaim/sda1: flags=0xc
[ 325.020293] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 325.022549] pending: xfs_reclaim_worker [xfs]
[ 325.024540] workqueue xfs-sync/sda1: flags=0x4
[ 325.026425] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 325.028691] pending: xfs_log_worker [xfs]
[ 325.030546] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=189s workers=4 idle: 977 65 13
[ 427.593034] sysrq: SysRq : Show Memory
[ 427.594680] Mem-Info:
[ 427.595882] active_anon:855844 inactive_anon:2123 isolated_anon:0
[ 427.595882] active_file:7 inactive_file:12 isolated_file:0
[ 427.595882] unevictable:0 dirty:0 writeback:0 unstable:0
[ 427.595882] slab_reclaimable:3444 slab_unreclaimable:22960
[ 427.595882] mapped:1743 shmem:2272 pagetables:3991 bounce:0
[ 427.595882] free:21254 free_pcp:165 free_cma:0
[ 427.607487] Node 0 active_anon:3423376kB inactive_anon:8492kB active_file:28kB inactive_file:48kB unevictable:0kB isolated(anon):0kB isolated(file):0kB mapped:6972kB dirty:0kB writeback:0kB shmem:9088kB shmem_thp: 0kB shmem_pmdmapped: 0kB anon_thp: 3227648kB writeback_tmp:0kB unstable:0kB all_unreclaimable? yes
[ 427.615694] Node 0 DMA free:14712kB min:288kB low:360kB high:432kB active_anon:1128kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:15960kB managed:15876kB mlocked:0kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 427.623632] lowmem_reserve[]: 0 2717 3607 3607
[ 427.625423] Node 0 DMA32 free:53860kB min:50684kB low:63352kB high:76020kB active_anon:2727108kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:3129152kB managed:2782536kB mlocked:0kB kernel_stack:0kB pagetables:4kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB
[ 427.634066] lowmem_reserve[]: 0 0 890 890
[ 427.635829] Node 0 Normal free:16444kB min:16608kB low:20760kB high:24912kB active_anon:694864kB inactive_anon:8492kB active_file:44kB inactive_file:0kB unevictable:0kB writepending:0kB present:1048576kB managed:911820kB mlocked:0kB kernel_stack:7444kB pagetables:15956kB bounce:0kB free_pcp:660kB local_pcp:660kB free_cma:0kB
[ 427.645560] lowmem_reserve[]: 0 0 0 0
[ 427.647320] Node 0 DMA: 0*4kB 1*8kB (M) 1*16kB (M) 1*32kB (U) 1*64kB (U) 2*128kB (UM) 2*256kB (UM) 1*512kB (M) 1*1024kB (U) 0*2048kB 3*4096kB (M) = 14712kB
[ 427.651757] Node 0 DMA32: 5*4kB (UM) 3*8kB (U) 5*16kB (U) 5*32kB (U) 5*64kB (U) 2*128kB (UM) 2*256kB (UM) 7*512kB (M) 4*1024kB (M) 2*2048kB (UM) 10*4096kB (UM) = 54108kB
[ 427.657428] Node 0 Normal: 13*4kB (UM) 5*8kB (UM) 2*16kB (U) 81*32kB (UME) 23*64kB (UME) 6*128kB (UME) 5*256kB (U) 2*512kB (UM) 9*1024kB (M) 0*2048kB 0*4096kB = 16476kB
[ 427.663144] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
[ 427.666283] 2273 total pagecache pages
[ 427.668249] 0 pages in swap cache
[ 427.670085] Swap cache stats: add 0, delete 0, find 0/0
[ 427.672416] Free swap = 0kB
[ 427.674256] Total swap = 0kB
[ 427.676011] 1048422 pages RAM
[ 427.677746] 0 pages HighMem/MovableOnly
[ 427.679704] 120864 pages reserved
[ 427.681526] 0 pages cma reserved
[ 427.683371] 0 pages hwpoisoned
[ 430.083584] kworker/0:0 R running task 13504 5 2 0x80000000
[ 430.085990] Workqueue: events_freezable_power_ disk_events_workfn
[ 430.088175] Call Trace:
[ 430.175214] ? shrink_slab+0x240/0x2c0
[ 430.176861] shrink_node+0xe3/0x460
[ 430.178402] do_try_to_free_pages+0xcb/0x380
[ 430.180110] try_to_free_pages+0xbb/0xf0
[ 430.181733] __alloc_pages_slowpath+0x3c1/0xc50
[ 430.183516] __alloc_pages_nodemask+0x2a6/0x2c0
[ 430.185292] bio_copy_kern+0xcd/0x200
[ 430.186847] blk_rq_map_kern+0xb6/0x130
[ 430.188475] scsi_execute+0x64/0x250
[ 430.190027] sr_check_events+0x9a/0x2b0 [sr_mod]
[ 430.191844] ? __mutex_unlock_slowpath+0x46/0x2b0
[ 430.193668] cdrom_check_events+0xf/0x30 [cdrom]
[ 430.195466] sr_block_check_events+0x7c/0xb0 [sr_mod]
[ 430.197383] disk_check_events+0x5e/0x150
[ 430.199038] process_one_work+0x290/0x4a0
[ 430.200712] ? process_one_work+0x227/0x4a0
[ 430.202413] worker_thread+0x28/0x3d0
[ 430.204003] ? process_one_work+0x4a0/0x4a0
[ 430.205757] kthread+0x107/0x120
[ 430.207282] ? kthread_create_worker_on_cpu+0x70/0x70
[ 430.209345] ret_from_fork+0x24/0x30
[ 444.206334] Showing busy workqueues and worker pools:
[ 444.208472] workqueue events: flags=0x0
[ 444.210193] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=15/256
[ 444.212389] pending: vmw_fb_dirty_flush [vmwgfx], vmstat_shepherd, vmpressure_work_fn, free_work, mmdrop_async_fn, mmdrop_async_fn, mmdrop_async_fn, mmdrop_async_fn, e1000_watchdog [e1000], mmdrop_async_fn, mmdrop_async_fn, check_corruption, console_callback, sysrq_reinject_alt_sysrq, moom_callback
[ 444.220547] workqueue events_freezable: flags=0x4
[ 444.222562] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 444.224852] pending: vmballoon_work [vmw_balloon]
[ 444.227022] workqueue events_power_efficient: flags=0x80
[ 444.229103] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=5/256
[ 444.231271] pending: gc_worker [nf_conntrack], fb_flashcursor, neigh_periodic_work, neigh_periodic_work, check_lifetime
[ 444.234824] workqueue events_freezable_power_: flags=0x84
[ 444.236937] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 444.239138] in-flight: 5:disk_events_workfn
[ 444.241022] workqueue mm_percpu_wq: flags=0x8
[ 444.242829] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=2/256
[ 444.245057] pending: vmstat_update, drain_local_pages_wq BAR(498)
[ 444.247646] workqueue ipv6_addrconf: flags=0x40008
[ 444.249582] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/1
[ 444.251784] pending: addrconf_verify_work
[ 444.253620] workqueue mpt_poll_0: flags=0x8
[ 444.255427] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 444.257666] pending: mpt_fault_reset_work [mptbase]
[ 444.259800] workqueue xfs-cil/sda1: flags=0xc
[ 444.261646] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 444.263903] pending: xlog_cil_push_work [xfs] BAR(2344)
[ 444.266101] workqueue xfs-reclaim/sda1: flags=0xc
[ 444.268104] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 444.270454] pending: xfs_reclaim_worker [xfs]
[ 444.272425] workqueue xfs-eofblocks/sda1: flags=0xc
[ 444.274432] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 444.276729] pending: xfs_eofblocks_worker [xfs]
[ 444.278739] workqueue xfs-sync/sda1: flags=0x4
[ 444.280641] pwq 0: cpus=0 node=0 flags=0x0 nice=0 active=1/256
[ 444.282967] pending: xfs_log_worker [xfs]
[ 444.285195] pool 0: cpus=0 node=0 flags=0x0 nice=0 hung=309s workers=3 idle: 977 65
Since the patch shown below was suggested by Michal Hocko at
https://marc.info/?l=linux-mm&m=152723708623015 , it is from Michal Hocko.
>From cd8095242de13ace61eefca0c3d6f2a5a7b40032 Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@...e.com>
Date: Thu, 26 Jul 2018 14:40:03 +0900
Subject: [PATCH] mm,page_alloc: PF_WQ_WORKER threads must sleep at should_reclaim_retry().
Tetsuo Handa has reported that it is possible to bypass the short sleep
for PF_WQ_WORKER threads which was introduced by commit 373ccbe5927034b5
("mm, vmstat: allow WQ concurrency to discover memory reclaim doesn't make
any progress") and moved by commit ede37713737834d9 ("mm: throttle on IO
only when there are too many dirty and writeback pages") and lock up the
system if OOM.
This is because we are implicitly counting on falling back to
schedule_timeout_uninterruptible() in __alloc_pages_may_oom() when
schedule_timeout_uninterruptible() in should_reclaim_retry() was not
called due to __zone_watermark_ok() == false.
However, schedule_timeout_uninterruptible() in __alloc_pages_may_oom() is
not called if all allocating threads but a PF_WQ_WORKER thread got stuck at
__GFP_FS direct reclaim, for mutex_trylock(&oom_lock) by that PF_WQ_WORKER
thread succeeds and out_of_memory() remains no-op unless that PF_WQ_WORKER
thread is doing __GFP_FS allocation. Tetsuo is observing that GFP_NOIO
allocation request from disk_events_workfn() is preventing other pending
works from starting.
Since should_reclaim_retry() should be a natural reschedule point,
let's do the short sleep for PF_WQ_WORKER threads unconditionally
in order to guarantee that other pending works are started.
Reported-by: Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Signed-off-by: Michal Hocko <mhocko@...e.com>
Cc: Roman Gushchin <guro@...com>
Cc: Johannes Weiner <hannes@...xchg.org>
Cc: Vladimir Davydov <vdavydov.dev@...il.com>
Cc: David Rientjes <rientjes@...gle.com>
Cc: Tejun Heo <tj@...nel.org>
---
mm/page_alloc.c | 34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a790ef4..0c2c0a2 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3922,6 +3922,7 @@ bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
{
struct zone *zone;
struct zoneref *z;
+ bool ret = false;
/*
* Costly allocations might have made a progress but this doesn't mean
@@ -3985,25 +3986,26 @@ bool gfp_pfmemalloc_allowed(gfp_t gfp_mask)
}
}
- /*
- * Memory allocation/reclaim might be called from a WQ
- * context and the current implementation of the WQ
- * concurrency control doesn't recognize that
- * a particular WQ is congested if the worker thread is
- * looping without ever sleeping. Therefore we have to
- * do a short sleep here rather than calling
- * cond_resched().
- */
- if (current->flags & PF_WQ_WORKER)
- schedule_timeout_uninterruptible(1);
- else
- cond_resched();
-
- return true;
+ ret = true;
+ goto out;
}
}
- return false;
+out:
+ /*
+ * Memory allocation/reclaim might be called from a WQ
+ * context and the current implementation of the WQ
+ * concurrency control doesn't recognize that
+ * a particular WQ is congested if the worker thread is
+ * looping without ever sleeping. Therefore we have to
+ * do a short sleep here rather than calling
+ * cond_resched().
+ */
+ if (current->flags & PF_WQ_WORKER)
+ schedule_timeout_uninterruptible(1);
+ else
+ cond_resched();
+ return ret;
}
static inline bool
--
1.8.3.1
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