The patch titled
Subject: mm: re-unify the simplified page_zap_*_rmap() function
has been added to the -mm mm-unstable branch. Its filename is
mm-re-unify-the-simplified-page_zap__rmap-function.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-re-unify-the-simplified-page_zap__rmap-function.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: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Subject: mm: re-unify the simplified page_zap_*_rmap() function
Date: Sun Oct 30 15:14:43 2022 -0700
Now that we've simplified both the anonymous and file-backed page zap
functions, they end up being identical except for which page statistic
they update, and we can re-unify the implementation of that much
simplified code.
To make it very clear that this is only for the final pte zapping (since a
lot of the simplifications depended on that), name the unified function
'page_zap_pte_rmap()'.
Link: https://lore.kernel.org/all/B88D3073-440A-41C7-95F4-895D3F657EF2@xxxxxxxxx/
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Aneesh Kumar <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/rmap.h | 3 +--
mm/memory.c | 5 ++---
mm/rmap.c | 39 +++++++++------------------------------
3 files changed, 12 insertions(+), 35 deletions(-)
--- a/include/linux/rmap.h~mm-re-unify-the-simplified-page_zap__rmap-function
+++ a/include/linux/rmap.h
@@ -196,8 +196,7 @@ void page_add_new_anon_rmap(struct page
unsigned long address);
void page_add_file_rmap(struct page *, struct vm_area_struct *,
bool compound);
-void page_zap_file_rmap(struct page *);
-void page_zap_anon_rmap(struct page *);
+void page_zap_pte_rmap(struct page *);
void page_remove_rmap(struct page *, struct vm_area_struct *,
bool compound);
--- a/mm/memory.c~mm-re-unify-the-simplified-page_zap__rmap-function
+++ a/mm/memory.c
@@ -1402,9 +1402,8 @@ again:
if (pte_young(ptent) &&
likely(!(vma->vm_flags & VM_SEQ_READ)))
mark_page_accessed(page);
- page_zap_file_rmap(page);
- } else
- page_zap_anon_rmap(page);
+ }
+ page_zap_pte_rmap(page);
munlock_vma_page(page, vma, false);
rss[mm_counter(page)]--;
if (unlikely(page_mapcount(page) < 0))
--- a/mm/rmap.c~mm-re-unify-the-simplified-page_zap__rmap-function
+++ a/mm/rmap.c
@@ -1413,47 +1413,26 @@ static void page_remove_anon_compound_rm
}
/**
- * page_zap_file_rmap - take down non-anon pte mapping from a page
+ * page_zap_pte_rmap - take down a pte mapping from a page
* @page: page to remove mapping from
*
- * This is the simplified form of page_remove_rmap(), with:
- * - we've already checked for '!PageAnon(page)'
- * - 'compound' is always false
- * - the caller does 'munlock_vma_page(page, vma, compound)' separately
- * which allows for a much simpler calling convention.
+ * This is the simplified form of page_remove_rmap(), that only
+ * deals with last-level pages, so 'compound' is always false,
+ * and the caller does 'munlock_vma_page(page, vma, compound)'
+ * separately.
*
- * The caller holds the pte lock.
- */
-void page_zap_file_rmap(struct page *page)
-{
- if (!atomic_add_negative(-1, &page->_mapcount))
- return;
-
- lock_page_memcg(page);
- __dec_lruvec_page_state(page, NR_FILE_MAPPED);
- unlock_page_memcg(page);
-}
-
-/**
- * page_zap_anon_rmap(page) - take down non-anon pte mapping from a page
- * @page: page to remove mapping from
- *
- * This is the simplified form of page_remove_rmap(), with:
- * - we've already checked for 'PageAnon(page)'
- * - 'compound' is always false
- * - the caller does 'munlock_vma_page(page, vma, compound)' separately
- * which allows for a much simpler calling convention.
+ * This allows for a much simpler calling convention and code.
*
* The caller holds the pte lock.
*/
-void page_zap_anon_rmap(struct page *page)
+void page_zap_pte_rmap(struct page *page)
{
- /* page still mapped by someone else? */
if (!atomic_add_negative(-1, &page->_mapcount))
return;
lock_page_memcg(page);
- __dec_lruvec_page_state(page, NR_ANON_MAPPED);
+ __dec_lruvec_page_state(page,
+ PageAnon(page) ? NR_ANON_MAPPED : NR_FILE_MAPPED);
unlock_page_memcg(page);
}
_
Patches currently in -mm which might be from torvalds@xxxxxxxxxxxxxxxxxxxx are
mm-introduce-simplified-versions-of-page_remove_rmap.patch
mm-inline-simpler-case-of-page_remove_file_rmap.patch
mm-re-unify-the-simplified-page_zap__rmap-function.patch
mm-delay-rmap-removal-until-after-tlb-flush.patch
