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Diffstat (limited to 'include/linux/page-flags.h')
-rw-r--r--include/linux/page-flags.h14
1 files changed, 14 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 96326594e55d..a1e143634946 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -94,6 +94,12 @@
/* 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
@@ -241,6 +247,14 @@ static inline void SetPageUptodate(struct page *page)
#define __SetPageCompound(page) __set_bit(PG_compound, &(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.
+ */
+#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)
+
#ifdef CONFIG_SWAP
#define PageSwapCache(page) test_bit(PG_swapcache, &(page)->flags)
#define SetPageSwapCache(page) set_bit(PG_swapcache, &(page)->flags)