| Message ID | 20240913084506.3606292-1-jingxiangzeng.cas@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [V2] mm/vmscan: wake up flushers conditionally to avoid cgroup OOM | expand |
On Fri, Sep 13, 2024 at 1:45 AM Jingxiang Zeng <jingxiangzeng.cas@gmail.com> wrote: > > From: Zeng Jingxiang <linuszeng@tencent.com> > > Commit 14aa8b2d5c2e ("mm/mglru: don't sync disk for each aging cycle") > removed the opportunity to wake up flushers during the MGLRU page > reclamation process can lead to an increased likelihood of triggering OOM > when encountering many dirty pages during reclamation on MGLRU. > > This leads to premature OOM if there are too many dirty pages in cgroup: > Killed > > dd invoked oom-killer: gfp_mask=0x101cca(GFP_HIGHUSER_MOVABLE|__GFP_WRITE), > order=0, oom_score_adj=0 > > Call Trace: > <TASK> > dump_stack_lvl+0x5f/0x80 > dump_stack+0x14/0x20 > dump_header+0x46/0x1b0 > oom_kill_process+0x104/0x220 > out_of_memory+0x112/0x5a0 > mem_cgroup_out_of_memory+0x13b/0x150 > try_charge_memcg+0x44f/0x5c0 > charge_memcg+0x34/0x50 > __mem_cgroup_charge+0x31/0x90 > filemap_add_folio+0x4b/0xf0 > __filemap_get_folio+0x1a4/0x5b0 > ? srso_return_thunk+0x5/0x5f > ? __block_commit_write+0x82/0xb0 > ext4_da_write_begin+0xe5/0x270 > generic_perform_write+0x134/0x2b0 > ext4_buffered_write_iter+0x57/0xd0 > ext4_file_write_iter+0x76/0x7d0 > ? selinux_file_permission+0x119/0x150 > ? srso_return_thunk+0x5/0x5f > ? srso_return_thunk+0x5/0x5f > vfs_write+0x30c/0x440 > ksys_write+0x65/0xe0 > __x64_sys_write+0x1e/0x30 > x64_sys_call+0x11c2/0x1d50 > do_syscall_64+0x47/0x110 > entry_SYSCALL_64_after_hwframe+0x76/0x7e > > memory: usage 308224kB, limit 308224kB, failcnt 2589 > swap: usage 0kB, limit 9007199254740988kB, failcnt 0 > > ... > file_dirty 303247360 > file_writeback 0 > ... > > oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=test, > mems_allowed=0,oom_memcg=/test,task_memcg=/test,task=dd,pid=4404,uid=0 > Memory cgroup out of memory: Killed process 4404 (dd) total-vm:10512kB, > anon-rss:1152kB, file-rss:1824kB, shmem-rss:0kB, UID:0 pgtables:76kB > oom_score_adj:0 > > The flusher wake up was removed to decrease SSD wearing, but if we are > seeing all dirty folios at the tail of an LRU, not waking up the flusher > could lead to thrashing easily. So wake it up when a mem cgroups is > about to OOM due to dirty caches. > > Link: https://lkml.kernel.org/r/20240829102543.189453-1-jingxiangzeng.cas@gmail.com > Fixes: 14aa8b2d5c2e ("mm/mglru: don't sync disk for each aging cycle") > Signed-off-by: Zeng Jingxiang <linuszeng@tencent.com> > Signed-off-by: Kairui Song <kasong@tencent.com> > Cc: T.J. Mercier <tjmercier@google.com> > Cc: Wei Xu <weixugc@google.com> > Cc: Yu Zhao <yuzhao@google.com> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > --- > mm/vmscan.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index 749cdc110c74..ce471d686a88 100644 > --- a/mm/vmscan.c > +++ b/mm/vmscan.c > @@ -4284,6 +4284,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, struct scan_c > int tier_idx) > { > bool success; > + bool dirty, writeback; > int gen = folio_lru_gen(folio); > int type = folio_is_file_lru(folio); > int zone = folio_zonenum(folio); > @@ -4332,6 +4333,9 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, struct scan_c > /* waiting for writeback */ > if (folio_test_locked(folio) || folio_test_writeback(folio) || > (type == LRU_GEN_FILE && folio_test_dirty(folio))) { > + folio_check_dirty_writeback(folio, &dirty, &writeback); We cannot simply call folio_check_dirty_writeback() here because folio_check_dirty_writeback() assumes that the folio is locked (e.g. see buffer_check_dirty_writeback()). > + if (dirty && !writeback) > + sc->nr.unqueued_dirty += delta; > gen = folio_inc_gen(lruvec, folio, true); > list_move(&folio->lru, &lrugen->folios[gen][type][zone]); > return true; > @@ -4448,6 +4452,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc, > scanned, skipped, isolated, > type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON); > > + sc->nr.taken += isolated; > /* > * There might not be eligible folios due to reclaim_idx. Check the > * remaining to prevent livelock if it's not making progress. > @@ -4920,6 +4925,14 @@ static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc > if (try_to_shrink_lruvec(lruvec, sc)) > lru_gen_rotate_memcg(lruvec, MEMCG_LRU_YOUNG); > > + /* > + * If too many pages failed to evict due to page being dirty, > + * memory pressure have pushed dirty pages to oldest gen, > + * wake up flusher. > + */ > + if (sc->nr.unqueued_dirty > sc->nr.taken) > + wakeup_flusher_threads(WB_REASON_VMSCAN); > + The wakeups will be much more often than intended because sc->nr.unqueued_dirty includes the drity file pages now, but sc->nr.taken doesn't. > clear_mm_walk(); > > blk_finish_plug(&plug); > -- > 2.43.5 >
diff --git a/mm/vmscan.c b/mm/vmscan.c index 749cdc110c74..ce471d686a88 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -4284,6 +4284,7 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, struct scan_c int tier_idx) { bool success; + bool dirty, writeback; int gen = folio_lru_gen(folio); int type = folio_is_file_lru(folio); int zone = folio_zonenum(folio); @@ -4332,6 +4333,9 @@ static bool sort_folio(struct lruvec *lruvec, struct folio *folio, struct scan_c /* waiting for writeback */ if (folio_test_locked(folio) || folio_test_writeback(folio) || (type == LRU_GEN_FILE && folio_test_dirty(folio))) { + folio_check_dirty_writeback(folio, &dirty, &writeback); + if (dirty && !writeback) + sc->nr.unqueued_dirty += delta; gen = folio_inc_gen(lruvec, folio, true); list_move(&folio->lru, &lrugen->folios[gen][type][zone]); return true; @@ -4448,6 +4452,7 @@ static int scan_folios(struct lruvec *lruvec, struct scan_control *sc, scanned, skipped, isolated, type ? LRU_INACTIVE_FILE : LRU_INACTIVE_ANON); + sc->nr.taken += isolated; /* * There might not be eligible folios due to reclaim_idx. Check the * remaining to prevent livelock if it's not making progress. @@ -4920,6 +4925,14 @@ static void lru_gen_shrink_lruvec(struct lruvec *lruvec, struct scan_control *sc if (try_to_shrink_lruvec(lruvec, sc)) lru_gen_rotate_memcg(lruvec, MEMCG_LRU_YOUNG); + /* + * If too many pages failed to evict due to page being dirty, + * memory pressure have pushed dirty pages to oldest gen, + * wake up flusher. + */ + if (sc->nr.unqueued_dirty > sc->nr.taken) + wakeup_flusher_threads(WB_REASON_VMSCAN); + clear_mm_walk(); blk_finish_plug(&plug);