#define PG_private 11 /* If pagecache, has fs-private data */
#define PG_writeback 12 /* Page is under writeback */
-#define PG_readahead 13 /* Reminder to do async read-ahead */
#define PG_compound 14 /* Part of a compound page */
#define PG_swapcache 15 /* Swap page: swp_entry_t in private */
#define PG_reclaim 17 /* To be reclaimed asap */
#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 */
#define PG_pinned PG_owner_priv_1 /* Xen pinned pagetable */
#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 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)