The patch titled
Subject: mm: mlock: avoid folio_within_range() on KSM pages
has been added to the -mm mm-unstable branch. Its filename is
mm-mlock-avoid-folio_within_range-on-ksm-pages.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-mlock-avoid-folio_within_range-on-ksm-pages.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: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mm: mlock: avoid folio_within_range() on KSM pages
Date: Mon, 23 Oct 2023 23:38:41 -0700 (PDT)
Since commit dc68badcede4 ("mm: mlock: update mlock_pte_range to handle
large folio") I've just occasionally seen VM_WARN_ON_FOLIO(folio_test_ksm)
warnings from folio_within_range(), in a splurge after testing with KSM
hyperactive.
folio_referenced_one()'s use of folio_within_vma() is safe because it
checks folio_test_large() first; but allow_mlock_munlock() needs to do the
same to avoid those warnings (or check !folio_test_ksm() itself? or move
either check into folio_within_range()? hard to tell without more
examples of its use).
Link: https://lkml.kernel.org/r/23852f6a-5bfa-1ffd-30db-30c5560ad426@xxxxxxxxxx
Fixes: dc68badcede4 ("mm: mlock: update mlock_pte_range to handle large folio")
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Reviewed-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Stefan Roesch <shr@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/mlock.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/mm/mlock.c~mm-mlock-avoid-folio_within_range-on-ksm-pages
+++ a/mm/mlock.c
@@ -346,6 +346,10 @@ static inline bool allow_mlock_munlock(s
if (!(vma->vm_flags & VM_LOCKED))
return true;
+ /* folio_within_range() cannot take KSM, but any small folio is OK */
+ if (!folio_test_large(folio))
+ return true;
+
/* folio not in range [start, end), skip mlock */
if (!folio_within_range(folio, vma, start, end))
return false;
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
hugetlbfs-drop-shared-numa-mempolicy-pretence.patch
kernfs-drop-shared-numa-mempolicy-hooks.patch
mempolicy-fix-migrate_pages2-syscall-return-nr_failed.patch
mempolicy-trivia-delete-those-ancient-pr_debugs.patch
mempolicy-trivia-slightly-more-consistent-naming.patch
mempolicy-trivia-use-pgoff_t-in-shared-mempolicy-tree.patch
mempolicy-mpol_shared_policy_init-without-pseudo-vma.patch
mempolicy-remove-confusing-mpol_mf_lazy-dead-code.patch
mm-add-page_rmappable_folio-wrapper.patch
mempolicy-alloc_pages_mpol-for-numa-policy-without-vma.patch
mempolicy-mmap_lock-is-not-needed-while-migrating-folios.patch
mempolicy-migration-attempt-to-match-interleave-nodes.patch
ext4-add-__gfp_nowarn-to-gfp_nowait-in-readahead.patch
mm-mlock-avoid-folio_within_range-on-ksm-pages.patch
