The patch titled
Subject: mm/rmap: drop stale comment in page_add_anon_rmap and hugepage_add_anon_rmap()
has been added to the -mm mm-unstable branch. Its filename is
mm-rmap-drop-stale-comment-in-page_add_anon_rmap-and-hugepage_add_anon_rmap.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-rmap-drop-stale-comment-in-page_add_anon_rmap-and-hugepage_add_anon_rmap.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: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/rmap: drop stale comment in page_add_anon_rmap and hugepage_add_anon_rmap()
Date: Wed, 13 Sep 2023 14:51:08 +0200
Patch series "Anon rmap cleanups".
Some cleanups around rmap for anon pages. I'm working on more cleanups
also around file rmap -- also to handle the "compound" parameter
internally only and to let hugetlb use page_add_file_rmap(), but these
changes make sense separately.
This patch (of 6):
That comment was added in commit 5dbe0af47f8a ("mm: fix kernel BUG at
mm/rmap.c:1017!") to document why we can see vma->vm_end getting adjusted
concurrently due to a VMA split.
However, the optimized locking code was changed again in bf181b9f9d8 ("mm
anon rmap: replace same_anon_vma linked list with an interval tree.").
... and later, the comment was changed in commit 0503ea8f5ba7 ("mm/mmap:
remove __vma_adjust()") to talk about "vma_merge" although the original
issue was with VMA splitting.
Let's just remove that comment. Nowadays, it's outdated, imprecise and
confusing.
Link: https://lkml.kernel.org/r/20230913125113.313322-1-david@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20230913125113.313322-2-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/rmap.c | 2 --
1 file changed, 2 deletions(-)
--- a/mm/rmap.c~mm-rmap-drop-stale-comment-in-page_add_anon_rmap-and-hugepage_add_anon_rmap
+++ a/mm/rmap.c
@@ -1245,7 +1245,6 @@ void page_add_anon_rmap(struct page *pag
__lruvec_stat_mod_folio(folio, NR_ANON_MAPPED, nr);
if (likely(!folio_test_ksm(folio))) {
- /* address might be in next vma when migration races vma_merge */
if (first)
__page_set_anon_rmap(folio, page, vma, address,
!!(flags & RMAP_EXCLUSIVE));
@@ -2536,7 +2535,6 @@ void hugepage_add_anon_rmap(struct page
BUG_ON(!folio_test_locked(folio));
BUG_ON(!anon_vma);
- /* address might be in next vma when migration races vma_merge */
first = atomic_inc_and_test(&folio->_entire_mapcount);
VM_BUG_ON_PAGE(!first && (flags & RMAP_EXCLUSIVE), page);
VM_BUG_ON_PAGE(!first && PageAnonExclusive(page), page);
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-rmap-drop-stale-comment-in-page_add_anon_rmap-and-hugepage_add_anon_rmap.patch
mm-rmap-move-setpageanonexclusive-out-of-__page_set_anon_rmap.patch
mm-rmap-move-folio_test_anon-check-out-of-__folio_set_anon.patch
mm-rmap-warn-on-new-pte-mapped-folios-in-page_add_anon_rmap.patch
mm-rmap-simplify-pageanonexclusive-sanity-checks-when-adding-anon-rmap.patch
mm-rmap-pass-folio-to-hugepage_add_anon_rmap.patch
