#define PAGE_FLAGS_H
#include <linux/types.h>
+#include <linux/mm_types.h>
/*
* Various page->flags bits:
#define PG_private 11 /* If pagecache, has fs-private data */
#define PG_writeback 12 /* Page is under writeback */
-#define PG_nosave 13 /* Used for system suspend/resume */
#define PG_compound 14 /* Part of a compound page */
#define PG_swapcache 15 /* Swap page: swp_entry_t in private */
#define PG_mappedtodisk 16 /* Has blocks allocated on-disk */
#define PG_reclaim 17 /* To be reclaimed asap */
-#define PG_nosave_free 18 /* Used for system suspend/resume */
#define PG_buddy 19 /* Page is free, on buddy lists */
+/* PG_readahead is only used for file reads; PG_reclaim is only for writes */
+#define PG_readahead PG_reclaim /* Reminder to do async read-ahead */
+
/* 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
+#define PG_pinned PG_owner_priv_1 /* Xen pinned pagetable */
#if (BITS_PER_LONG > 32)
/*
#define SetPageChecked(page) set_bit(PG_checked, &(page)->flags)
#define ClearPageChecked(page) clear_bit(PG_checked, &(page)->flags)
+#define PagePinned(page) test_bit(PG_pinned, &(page)->flags)
+#define SetPagePinned(page) set_bit(PG_pinned, &(page)->flags)
+#define ClearPagePinned(page) clear_bit(PG_pinned, &(page)->flags)
+
#define PageReserved(page) test_bit(PG_reserved, &(page)->flags)
#define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags)
#define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
#define __SetPagePrivate(page) __set_bit(PG_private, &(page)->flags)
#define __ClearPagePrivate(page) __clear_bit(PG_private, &(page)->flags)
+/*
+ * Only test-and-set exist for PG_writeback. The unconditional operators are
+ * risky: they bypass page accounting.
+ */
#define PageWriteback(page) test_bit(PG_writeback, &(page)->flags)
-#define SetPageWriteback(page) \
- do { \
- if (!test_and_set_bit(PG_writeback, \
- &(page)->flags)) \
- inc_zone_page_state(page, NR_WRITEBACK); \
- } while (0)
-#define TestSetPageWriteback(page) \
- ({ \
- int ret; \
- ret = test_and_set_bit(PG_writeback, \
- &(page)->flags); \
- if (!ret) \
- inc_zone_page_state(page, NR_WRITEBACK); \
- ret; \
- })
-#define ClearPageWriteback(page) \
- do { \
- if (test_and_clear_bit(PG_writeback, \
- &(page)->flags)) \
- dec_zone_page_state(page, NR_WRITEBACK); \
- } while (0)
-#define TestClearPageWriteback(page) \
- ({ \
- int ret; \
- ret = test_and_clear_bit(PG_writeback, \
- &(page)->flags); \
- if (ret) \
- dec_zone_page_state(page, NR_WRITEBACK); \
- ret; \
- })
-
-#define PageNosave(page) test_bit(PG_nosave, &(page)->flags)
-#define SetPageNosave(page) set_bit(PG_nosave, &(page)->flags)
-#define TestSetPageNosave(page) test_and_set_bit(PG_nosave, &(page)->flags)
-#define ClearPageNosave(page) clear_bit(PG_nosave, &(page)->flags)
-#define TestClearPageNosave(page) test_and_clear_bit(PG_nosave, &(page)->flags)
-
-#define PageNosaveFree(page) test_bit(PG_nosave_free, &(page)->flags)
-#define SetPageNosaveFree(page) set_bit(PG_nosave_free, &(page)->flags)
-#define ClearPageNosaveFree(page) clear_bit(PG_nosave_free, &(page)->flags)
+#define TestSetPageWriteback(page) test_and_set_bit(PG_writeback, \
+ &(page)->flags)
+#define TestClearPageWriteback(page) test_and_clear_bit(PG_writeback, \
+ &(page)->flags)
#define PageBuddy(page) test_bit(PG_buddy, &(page)->flags)
#define __SetPageBuddy(page) __set_bit(PG_buddy, &(page)->flags)
#define SetPageMappedToDisk(page) set_bit(PG_mappedtodisk, &(page)->flags)
#define ClearPageMappedToDisk(page) clear_bit(PG_mappedtodisk, &(page)->flags)
+#define PageReadahead(page) test_bit(PG_readahead, &(page)->flags)
+#define SetPageReadahead(page) set_bit(PG_readahead, &(page)->flags)
+#define ClearPageReadahead(page) clear_bit(PG_readahead, &(page)->flags)
+
#define PageReclaim(page) test_bit(PG_reclaim, &(page)->flags)
#define SetPageReclaim(page) set_bit(PG_reclaim, &(page)->flags)
#define ClearPageReclaim(page) clear_bit(PG_reclaim, &(page)->flags)
#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)
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