The patch titled
Subject: mm: simplify PageDoubleMap with PF_SECOND policy
has been added to the -mm tree. Its filename is
mm-simplify-pagedoublemap-with-pf_second-policy.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-simplify-pagedoublemap-with-pf_second-policy.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-simplify-pagedoublemap-with-pf_second-policy.patch
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: mm: simplify PageDoubleMap with PF_SECOND policy
Introduce the new page policy of PF_SECOND which lets us use the normal
pageflags generation machinery to create the various DoubleMap
manipulation functions.
Link: https://lkml.kernel.org/r/20200629151933.15671-3-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Zi Yan <ziy@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/page-flags.h | 40 ++++++++---------------------------
1 file changed, 10 insertions(+), 30 deletions(-)
--- a/include/linux/page-flags.h~mm-simplify-pagedoublemap-with-pf_second-policy
+++ a/include/linux/page-flags.h
@@ -232,6 +232,9 @@ static inline void page_init_poison(stru
*
* PF_NO_COMPOUND:
* the page flag is not relevant for compound pages.
+ *
+ * PF_SECOND:
+ * the page flag is stored in the first tail page.
*/
#define PF_POISONED_CHECK(page) ({ \
VM_BUG_ON_PGFLAGS(PagePoisoned(page), page); \
@@ -247,6 +250,9 @@ static inline void page_init_poison(stru
#define PF_NO_COMPOUND(page, enforce) ({ \
VM_BUG_ON_PGFLAGS(enforce && PageCompound(page), page); \
PF_POISONED_CHECK(page); })
+#define PF_SECOND(page, enforce) ({ \
+ VM_BUG_ON_PGFLAGS(!PageHead(page), page); \
+ PF_POISONED_CHECK(&page[1]); })
/*
* Macros to create function definitions for page flags
@@ -685,42 +691,15 @@ static inline int PageTransTail(struct p
*
* See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
*/
-static inline int PageDoubleMap(struct page *page)
-{
- return PageHead(page) && test_bit(PG_double_map, &page[1].flags);
-}
-
-static inline void SetPageDoubleMap(struct page *page)
-{
- VM_BUG_ON_PAGE(!PageHead(page), page);
- set_bit(PG_double_map, &page[1].flags);
-}
-
-static inline void ClearPageDoubleMap(struct page *page)
-{
- VM_BUG_ON_PAGE(!PageHead(page), page);
- clear_bit(PG_double_map, &page[1].flags);
-}
-static inline int TestSetPageDoubleMap(struct page *page)
-{
- VM_BUG_ON_PAGE(!PageHead(page), page);
- return test_and_set_bit(PG_double_map, &page[1].flags);
-}
-
-static inline int TestClearPageDoubleMap(struct page *page)
-{
- VM_BUG_ON_PAGE(!PageHead(page), page);
- return test_and_clear_bit(PG_double_map, &page[1].flags);
-}
-
+PAGEFLAG(DoubleMap, double_map, PF_SECOND)
+ TESTSCFLAG(DoubleMap, double_map, PF_SECOND)
#else
TESTPAGEFLAG_FALSE(TransHuge)
TESTPAGEFLAG_FALSE(TransCompound)
TESTPAGEFLAG_FALSE(TransCompoundMap)
TESTPAGEFLAG_FALSE(TransTail)
PAGEFLAG_FALSE(DoubleMap)
- TESTSETFLAG_FALSE(DoubleMap)
- TESTCLEARFLAG_FALSE(DoubleMap)
+ TESTSCFLAG_FALSE(DoubleMap)
#endif
/*
@@ -885,6 +864,7 @@ static inline int page_has_private(struc
#undef PF_ONLY_HEAD
#undef PF_NO_TAIL
#undef PF_NO_COMPOUND
+#undef PF_SECOND
#endif /* !__GENERATING_BOUNDS_H */
#endif /* PAGE_FLAGS_H */
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-debug-do-not-dereference-i_ino-blindly.patch
mm-account-pmd-tables-like-pte-tables.patch
mm-move-pagedoublemap-bit.patch
mm-simplify-pagedoublemap-with-pf_second-policy.patch
harden-autofs-ioctl-table.patch
