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authorDavid Howells <dhowells@redhat.com>2009-04-03 16:42:36 +0100
committerDavid Howells <dhowells@redhat.com>2009-04-03 16:42:36 +0100
commit266cf658efcf6ac33541a46740f74f50c79d2b6b (patch)
tree5c83b0879892d509e598dfd54be3ba3679ecd348 /include
parent03fb3d2af96c2783c3a5bc03f3d984cf422f0e69 (diff)
FS-Cache: Recruit a page flags for cache management
Recruit a page flag to aid in cache management. The following extra flag is defined: (1) PG_fscache (PG_private_2) The marked page is backed by a local cache and is pinning resources in the cache driver. If PG_fscache is set, then things that checked for PG_private will now also check for that. This includes things like truncation and page invalidation. The function page_has_private() had been added to make the checks for both PG_private and PG_private_2 at the same time. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Steve Dickson <steved@redhat.com> Acked-by: Trond Myklebust <Trond.Myklebust@netapp.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Al Viro <viro@zeniv.linux.org.uk> Tested-by: Daire Byrne <Daire.Byrne@framestore.com>
Diffstat (limited to 'include')
-rw-r--r--include/linux/page-flags.h38
1 files changed, 33 insertions, 5 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 9d99e7471ad..62214c7d2d9 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -82,6 +82,7 @@ enum pageflags {
PG_arch_1,
PG_reserved,
PG_private, /* If pagecache, has fs-private data */
+ PG_private_2, /* If pagecache, has fs aux data */
PG_writeback, /* Page is under writeback */
#ifdef CONFIG_PAGEFLAGS_EXTENDED
PG_head, /* A head page */
@@ -108,6 +109,12 @@ enum pageflags {
/* Filesystems */
PG_checked = PG_owner_priv_1,
+ /* Two page bits are conscripted by FS-Cache to maintain local caching
+ * state. These bits are set on pages belonging to the netfs's inodes
+ * when those inodes are being locally cached.
+ */
+ PG_fscache = PG_private_2, /* page backed by cache */
+
/* XEN */
PG_pinned = PG_owner_priv_1,
PG_savepinned = PG_dirty,
@@ -194,8 +201,6 @@ PAGEFLAG(Checked, checked) /* Used by some filesystems */
PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
PAGEFLAG(SavePinned, savepinned); /* Xen */
PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
-PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private)
- __SETPAGEFLAG(Private, private)
PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
__PAGEFLAG(SlobPage, slob_page)
@@ -205,6 +210,16 @@ __PAGEFLAG(SlubFrozen, slub_frozen)
__PAGEFLAG(SlubDebug, slub_debug)
/*
+ * Private page markings that may be used by the filesystem that owns the page
+ * for its own purposes.
+ * - PG_private and PG_private_2 cause releasepage() and co to be invoked
+ */
+PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private)
+ __CLEARPAGEFLAG(Private, private)
+PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2)
+PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)
+
+/*
* Only test-and-set exist for PG_writeback. The unconditional operators are
* risky: they bypass page accounting.
*/
@@ -384,9 +399,10 @@ static inline void __ClearPageTail(struct page *page)
* these flags set. It they are, there is a problem.
*/
#define PAGE_FLAGS_CHECK_AT_FREE \
- (1 << PG_lru | 1 << PG_private | 1 << PG_locked | \
- 1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \
- 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
+ (1 << PG_lru | 1 << PG_locked | \
+ 1 << PG_private | 1 << PG_private_2 | \
+ 1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \
+ 1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
__PG_UNEVICTABLE | __PG_MLOCKED)
/*
@@ -397,4 +413,16 @@ static inline void __ClearPageTail(struct page *page)
#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
#endif /* !__GENERATING_BOUNDS_H */
+
+/**
+ * page_has_private - Determine if page has private stuff
+ * @page: The page to be checked
+ *
+ * Determine if a page has private stuff, indicating that release routines
+ * should be invoked upon it.
+ */
+#define page_has_private(page) \
+ ((page)->flags & ((1 << PG_private) | \
+ (1 << PG_private_2)))
+
#endif /* PAGE_FLAGS_H */