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 @@ -235,6 +235,9 @@ 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); \ @@ -250,6 +253,9 @@ 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 @@ -688,42 +694,15 @@ 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 /* @@ -888,6 +867,7 @@ 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 */ _
