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author | David Howells <dhowells@redhat.com> | 2009-04-03 16:42:36 +0100 |
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committer | David Howells <dhowells@redhat.com> | 2009-04-03 16:42:36 +0100 |
commit | 266cf658efcf6ac33541a46740f74f50c79d2b6b (patch) | |
tree | 5c83b0879892d509e598dfd54be3ba3679ecd348 /include | |
parent | 03fb3d2af96c2783c3a5bc03f3d984cf422f0e69 (diff) | |
download | linux-stable-266cf658efcf6ac33541a46740f74f50c79d2b6b.tar.gz linux-stable-266cf658efcf6ac33541a46740f74f50c79d2b6b.tar.bz2 linux-stable-266cf658efcf6ac33541a46740f74f50c79d2b6b.zip |
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.h | 38 |
1 files changed, 33 insertions, 5 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 9d99e7471ade..62214c7d2d93 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 */ |