The patch titled
Subject: mm/vmscan: don't try to reclaim freed folios
has been added to the -mm mm-unstable branch. Its filename is
mm-vmscan-dont-try-to-reclaim-freed-folios.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmscan-dont-try-to-reclaim-freed-folios.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/vmscan: don't try to reclaim freed folios
Date: Wed, 8 Jun 2022 22:14:32 +0800
If folios were freed from under us, there's no need to reclaim them. Skip
these folios to save lots of cpu cycles and avoid possible unnecessary
disk I/O.
Link: https://lkml.kernel.org/r/20220608141432.23258-1-linmiaohe@xxxxxxxxxx
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/mm/vmscan.c~mm-vmscan-dont-try-to-reclaim-freed-folios
+++ a/mm/vmscan.c
@@ -1610,13 +1610,19 @@ retry:
folio = lru_to_folio(page_list);
list_del(&folio->lru);
+ nr_pages = folio_nr_pages(folio);
+
+ if (folio_ref_count(folio) == 1 &&
+ folio_ref_freeze(folio, 1)) {
+ /* folio was freed from under us. So we are done. */
+ goto free_it;
+ }
+
if (!folio_trylock(folio))
goto keep;
VM_BUG_ON_FOLIO(folio_test_active(folio), folio);
- nr_pages = folio_nr_pages(folio);
-
/* Account the number of base pages */
sc->nr_scanned += nr_pages;
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
maintainers-add-myself-as-a-memory-failure-reviewer.patch
mm-shmemc-clean-up-comment-of-shmem_swapin_folio.patch
mm-reduce-the-rcu-lock-duration.patch
mm-migration-remove-unneeded-lock-page-and-pagemovable-check.patch
mm-migration-return-errno-when-isolate_huge_page-failed.patch
mm-migration-fix-potential-pte_unmap-on-an-not-mapped-pte.patch
mm-memremap-fix-wrong-function-name-above-memremap_pages.patch
mm-swapfile-make-security_vm_enough_memory_mm-work-as-expected.patch
mm-swapfile-fix-possible-data-races-of-inuse_pages.patch
mm-swap-remove-swap_cache_info-statistics.patch
mm-vmscan-dont-try-to-reclaim-freed-folios.patch
