The patch titled
Subject: mm: introduce page_mapcount_is_type()
has been added to the -mm mm-unstable branch. Its filename is
mm-introduce-page_mapcount_is_type.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-introduce-page_mapcount_is_type.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: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: introduce page_mapcount_is_type()
Date: Wed, 21 Aug 2024 18:39:10 +0100
Resolve the awkward "and add one to this opaque constant" test into a
self-documenting inline function.
Link: https://lkml.kernel.org/r/20240821173914.2270383-3-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/internal.h | 3 +--
include/linux/mm.h | 3 +--
include/linux/page-flags.h | 12 +++++++++---
3 files changed, 11 insertions(+), 7 deletions(-)
--- a/fs/proc/internal.h~mm-introduce-page_mapcount_is_type
+++ a/fs/proc/internal.h
@@ -166,8 +166,7 @@ static inline int folio_precise_page_map
{
int mapcount = atomic_read(&page->_mapcount) + 1;
- /* Handle page_has_type() pages */
- if (mapcount < PAGE_MAPCOUNT_RESERVE + 1)
+ if (page_mapcount_is_type(mapcount))
mapcount = 0;
if (folio_test_large(folio))
mapcount += folio_entire_mapcount(folio);
--- a/include/linux/mm.h~mm-introduce-page_mapcount_is_type
+++ a/include/linux/mm.h
@@ -1228,8 +1228,7 @@ static inline int folio_mapcount(const s
if (likely(!folio_test_large(folio))) {
mapcount = atomic_read(&folio->_mapcount) + 1;
- /* Handle page_has_type() pages */
- if (mapcount < PAGE_MAPCOUNT_RESERVE + 1)
+ if (page_mapcount_is_type(mapcount))
mapcount = 0;
return mapcount;
}
--- a/include/linux/page-flags.h~mm-introduce-page_mapcount_is_type
+++ a/include/linux/page-flags.h
@@ -956,12 +956,18 @@ enum pagetype {
#define folio_test_type(folio, flag) \
((READ_ONCE(folio->page.page_type) & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
-static inline int page_type_has_type(unsigned int page_type)
+static inline bool page_type_has_type(int page_type)
{
- return (int)page_type < PAGE_MAPCOUNT_RESERVE;
+ return page_type < PAGE_MAPCOUNT_RESERVE;
}
-static inline int page_has_type(const struct page *page)
+/* This takes a mapcount which is one more than page->_mapcount */
+static inline bool page_mapcount_is_type(unsigned int mapcount)
+{
+ return page_type_has_type(mapcount - 1);
+}
+
+static inline bool page_has_type(const struct page *page)
{
return page_type_has_type(READ_ONCE(page->page_type));
}
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
fs-remove-calls-to-set-and-clear-the-folio-error-flag.patch
mm-remove-pg_error.patch
mm-return-the-folio-from-swapin_readahead.patch
printf-remove-%pgt-support.patch
mm-introduce-page_mapcount_is_type.patch
mm-support-only-one-page_type-per-page.patch
zsmalloc-use-all-available-24-bits-of-page_type.patch
