diff options
Diffstat (limited to 'include/linux/page-flags.h')
| -rw-r--r-- | include/linux/page-flags.h | 37 |
1 files changed, 26 insertions, 11 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index a1e143634946..a3c8b60a9c3a 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -6,6 +6,7 @@ #define PAGE_FLAGS_H #include <linux/types.h> +#include <linux/mm_types.h> /* * Various page->flags bits: @@ -94,12 +95,6 @@ /* PG_owner_priv_1 users should have descriptive aliases */ #define PG_checked PG_owner_priv_1 /* Used by some filesystems */ -/* - * Marks tail portion of a compound page. We currently do not reclaim - * compound pages so we can reuse a flag only used for reclaim here. - */ -#define PG_tail PG_reclaim - #if (BITS_PER_LONG > 32) /* * 64-bit-only flags build down from bit 31 @@ -248,12 +243,32 @@ static inline void SetPageUptodate(struct page *page) #define __ClearPageCompound(page) __clear_bit(PG_compound, &(page)->flags) /* - * Note: PG_tail is an alias of another page flag. The result of PageTail() - * is only valid if PageCompound(page) is true. + * PG_reclaim is used in combination with PG_compound to mark the + * head and tail of a compound page + * + * PG_compound & PG_reclaim => Tail page + * PG_compound & ~PG_reclaim => Head page */ -#define PageTail(page) test_bit(PG_tail, &(page)->flags) -#define __SetPageTail(page) __set_bit(PG_tail, &(page)->flags) -#define __ClearPageTail(page) __clear_bit(PG_tail, &(page)->flags) + +#define PG_head_tail_mask ((1L << PG_compound) | (1L << PG_reclaim)) + +#define PageTail(page) ((page->flags & PG_head_tail_mask) \ + == PG_head_tail_mask) + +static inline void __SetPageTail(struct page *page) +{ + page->flags |= PG_head_tail_mask; +} + +static inline void __ClearPageTail(struct page *page) +{ + page->flags &= ~PG_head_tail_mask; +} + +#define PageHead(page) ((page->flags & PG_head_tail_mask) \ + == (1L << PG_compound)) +#define __SetPageHead(page) __SetPageCompound(page) +#define __ClearPageHead(page) __ClearPageCompound(page) #ifdef CONFIG_SWAP #define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags) |