The patch titled
Subject: mm: vmscan.c: fix OOM on swap stress test
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-vmscanc-fix-oom-on-swap-stress-test.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmscanc-fix-oom-on-swap-stress-test.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Chris Li <chrisl@xxxxxxxxxx>
Subject: mm: vmscan.c: fix OOM on swap stress test
Date: Thu, 05 Sep 2024 01:08:17 -0700
I found a regression on mm-unstable during my swap stress test, using
tmpfs to compile linux. The test OOM very soon after the make spawns many
cc processes.
It bisects down to this change: 33dfe9204f29b415bbc0abb1a50642d1ba94f5e9
(mm/gup: clear the LRU flag of a page before adding to LRU batch)
Yu Zhao propose the fix: "I think this is one of the potential side
effects -- Huge mentioned earlier about isolate_lru_folios():"
I test that with it the swap stress test no longer OOM.
Link: https://lore.kernel.org/r/CAOUHufYi9h0kz5uW3LHHS3ZrVwEq-kKp8S6N-MZUmErNAXoXmw@xxxxxxxxxxxxxx/
Link: https://lkml.kernel.org/r/20240905-lru-flag-v2-1-8a2d9046c594@xxxxxxxxxx
Fixes: 33dfe9204f29 ("mm/gup: clear the LRU flag of a page before adding to LRU batch")
Signed-off-by: Chris Li <chrisl@xxxxxxxxxx>
Suggested-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Suggested-by: Hugh Dickins <hughd@xxxxxxxxxx>
Closes: https://lore.kernel.org/all/CAF8kJuNP5iTj2p07QgHSGOJsiUfYpJ2f4R1Q5-3BN9JiD9W_KA@xxxxxxxxxxxxxx/
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/vmscan.c~mm-vmscanc-fix-oom-on-swap-stress-test
+++ a/mm/vmscan.c
@@ -4300,7 +4300,7 @@ static bool sort_folio(struct lruvec *lr
}
/* ineligible */
- if (zone > sc->reclaim_idx) {
+ if (!folio_test_lru(folio) || zone > sc->reclaim_idx) {
gen = folio_inc_gen(lruvec, folio, false);
list_move_tail(&folio->lru, &lrugen->folios[gen][type][zone]);
return true;
_
Patches currently in -mm which might be from chrisl@xxxxxxxxxx are
mm-vmscanc-fix-oom-on-swap-stress-test.patch
