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>
This commit is contained in:
David Howells
Родитель
03fb3d2af9
Коммит
266cf658ef
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@ -59,7 +59,8 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
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*/
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wait_on_page_writeback(page);
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if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL))
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if (page_has_private(page) &&
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!try_to_release_page(page, GFP_KERNEL))
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goto out_unlock;
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/*
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@ -82,6 +82,7 @@ enum pageflags {
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PG_arch_1,
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PG_reserved,
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PG_private, /* If pagecache, has fs-private data */
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PG_private_2, /* If pagecache, has fs aux data */
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PG_writeback, /* Page is under writeback */
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#ifdef CONFIG_PAGEFLAGS_EXTENDED
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PG_head, /* A head page */
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@ -108,6 +109,12 @@ enum pageflags {
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/* Filesystems */
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PG_checked = PG_owner_priv_1,
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/* Two page bits are conscripted by FS-Cache to maintain local caching
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* state. These bits are set on pages belonging to the netfs's inodes
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* when those inodes are being locally cached.
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*/
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PG_fscache = PG_private_2, /* page backed by cache */
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/* XEN */
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PG_pinned = PG_owner_priv_1,
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PG_savepinned = PG_dirty,
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@ -194,8 +201,6 @@ PAGEFLAG(Checked, checked) /* Used by some filesystems */
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PAGEFLAG(Pinned, pinned) TESTSCFLAG(Pinned, pinned) /* Xen */
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PAGEFLAG(SavePinned, savepinned); /* Xen */
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PAGEFLAG(Reserved, reserved) __CLEARPAGEFLAG(Reserved, reserved)
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PAGEFLAG(Private, private) __CLEARPAGEFLAG(Private, private)
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__SETPAGEFLAG(Private, private)
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PAGEFLAG(SwapBacked, swapbacked) __CLEARPAGEFLAG(SwapBacked, swapbacked)
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__PAGEFLAG(SlobPage, slob_page)
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@ -204,6 +209,16 @@ __PAGEFLAG(SlobFree, slob_free)
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__PAGEFLAG(SlubFrozen, slub_frozen)
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__PAGEFLAG(SlubDebug, slub_debug)
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/*
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* Private page markings that may be used by the filesystem that owns the page
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* for its own purposes.
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* - PG_private and PG_private_2 cause releasepage() and co to be invoked
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*/
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PAGEFLAG(Private, private) __SETPAGEFLAG(Private, private)
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__CLEARPAGEFLAG(Private, private)
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PAGEFLAG(Private2, private_2) TESTSCFLAG(Private2, private_2)
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PAGEFLAG(OwnerPriv1, owner_priv_1) TESTCLEARFLAG(OwnerPriv1, owner_priv_1)
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/*
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* Only test-and-set exist for PG_writeback. The unconditional operators are
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* risky: they bypass page accounting.
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@ -384,9 +399,10 @@ static inline void __ClearPageTail(struct page *page)
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* these flags set. It they are, there is a problem.
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*/
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#define PAGE_FLAGS_CHECK_AT_FREE \
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(1 << PG_lru | 1 << PG_private | 1 << PG_locked | \
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1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \
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1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
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(1 << PG_lru | 1 << PG_locked | \
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1 << PG_private | 1 << PG_private_2 | \
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1 << PG_buddy | 1 << PG_writeback | 1 << PG_reserved | \
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1 << PG_slab | 1 << PG_swapcache | 1 << PG_active | \
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__PG_UNEVICTABLE | __PG_MLOCKED)
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/*
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@ -397,4 +413,16 @@ static inline void __ClearPageTail(struct page *page)
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#define PAGE_FLAGS_CHECK_AT_PREP ((1 << NR_PAGEFLAGS) - 1)
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#endif /* !__GENERATING_BOUNDS_H */
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/**
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* page_has_private - Determine if page has private stuff
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* @page: The page to be checked
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*
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* Determine if a page has private stuff, indicating that release routines
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* should be invoked upon it.
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*/
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#define page_has_private(page) \
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((page)->flags & ((1 << PG_private) | \
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(1 << PG_private_2)))
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#endif /* PAGE_FLAGS_H */
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@ -2463,6 +2463,9 @@ EXPORT_SYMBOL(generic_file_aio_write);
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* (presumably at page->private). If the release was successful, return `1'.
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* Otherwise return zero.
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*
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* This may also be called if PG_fscache is set on a page, indicating that the
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* page is known to the local caching routines.
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*
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* The @gfp_mask argument specifies whether I/O may be performed to release
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* this page (__GFP_IO), and whether the call may block (__GFP_WAIT & __GFP_FS).
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*
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10
mm/migrate.c
10
mm/migrate.c
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@ -250,7 +250,7 @@ out:
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* The number of remaining references must be:
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* 1 for anonymous pages without a mapping
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* 2 for pages with a mapping
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* 3 for pages with a mapping and PagePrivate set.
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* 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
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*/
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static int migrate_page_move_mapping(struct address_space *mapping,
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struct page *newpage, struct page *page)
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@ -270,7 +270,7 @@ static int migrate_page_move_mapping(struct address_space *mapping,
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pslot = radix_tree_lookup_slot(&mapping->page_tree,
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page_index(page));
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expected_count = 2 + !!PagePrivate(page);
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expected_count = 2 + !!page_has_private(page);
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if (page_count(page) != expected_count ||
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(struct page *)radix_tree_deref_slot(pslot) != page) {
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spin_unlock_irq(&mapping->tree_lock);
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@ -386,7 +386,7 @@ EXPORT_SYMBOL(fail_migrate_page);
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/*
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* Common logic to directly migrate a single page suitable for
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* pages that do not use PagePrivate.
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* pages that do not use PagePrivate/PagePrivate2.
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*
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* Pages are locked upon entry and exit.
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*/
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@ -522,7 +522,7 @@ static int fallback_migrate_page(struct address_space *mapping,
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* Buffers may be managed in a filesystem specific way.
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* We must have no buffers or drop them.
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*/
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if (PagePrivate(page) &&
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if (page_has_private(page) &&
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!try_to_release_page(page, GFP_KERNEL))
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return -EAGAIN;
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@ -655,7 +655,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
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* free the metadata, so the page can be freed.
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*/
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if (!page->mapping) {
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if (!PageAnon(page) && PagePrivate(page)) {
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if (!PageAnon(page) && page_has_private(page)) {
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/*
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* Go direct to try_to_free_buffers() here because
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* a) that's what try_to_release_page() would do anyway
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@ -33,14 +33,15 @@ EXPORT_SYMBOL_GPL(file_ra_state_init);
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/*
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* see if a page needs releasing upon read_cache_pages() failure
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* - the caller of read_cache_pages() may have set PG_private before calling,
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* such as the NFS fs marking pages that are cached locally on disk, thus we
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* need to give the fs a chance to clean up in the event of an error
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* - the caller of read_cache_pages() may have set PG_private or PG_fscache
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* before calling, such as the NFS fs marking pages that are cached locally
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* on disk, thus we need to give the fs a chance to clean up in the event of
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* an error
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*/
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static void read_cache_pages_invalidate_page(struct address_space *mapping,
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struct page *page)
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{
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if (PagePrivate(page)) {
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if (page_has_private(page)) {
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if (!trylock_page(page))
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BUG();
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page->mapping = mapping;
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@ -448,8 +448,8 @@ void pagevec_strip(struct pagevec *pvec)
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for (i = 0; i < pagevec_count(pvec); i++) {
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struct page *page = pvec->pages[i];
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if (PagePrivate(page) && trylock_page(page)) {
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if (PagePrivate(page))
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if (page_has_private(page) && trylock_page(page)) {
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if (page_has_private(page))
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try_to_release_page(page, 0);
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unlock_page(page);
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}
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@ -50,7 +50,7 @@ void do_invalidatepage(struct page *page, unsigned long offset)
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static inline void truncate_partial_page(struct page *page, unsigned partial)
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{
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zero_user_segment(page, partial, PAGE_CACHE_SIZE);
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if (PagePrivate(page))
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if (page_has_private(page))
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do_invalidatepage(page, partial);
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}
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@ -99,7 +99,7 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
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if (page->mapping != mapping)
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return;
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if (PagePrivate(page))
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if (page_has_private(page))
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do_invalidatepage(page, 0);
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cancel_dirty_page(page, PAGE_CACHE_SIZE);
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@ -126,7 +126,7 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)
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if (page->mapping != mapping)
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return 0;
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if (PagePrivate(page) && !try_to_release_page(page, 0))
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if (page_has_private(page) && !try_to_release_page(page, 0))
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return 0;
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clear_page_mlock(page);
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@ -348,7 +348,7 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
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if (page->mapping != mapping)
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return 0;
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if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL))
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if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL))
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return 0;
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spin_lock_irq(&mapping->tree_lock);
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@ -356,7 +356,7 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
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goto failed;
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clear_page_mlock(page);
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BUG_ON(PagePrivate(page));
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BUG_ON(page_has_private(page));
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__remove_from_page_cache(page);
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spin_unlock_irq(&mapping->tree_lock);
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page_cache_release(page); /* pagecache ref */
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@ -283,7 +283,7 @@ static inline int page_mapping_inuse(struct page *page)
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static inline int is_page_cache_freeable(struct page *page)
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{
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return page_count(page) - !!PagePrivate(page) == 2;
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return page_count(page) - !!page_has_private(page) == 2;
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}
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static int may_write_to_queue(struct backing_dev_info *bdi)
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@ -367,7 +367,7 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
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* Some data journaling orphaned pages can have
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* page->mapping == NULL while being dirty with clean buffers.
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*/
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if (PagePrivate(page)) {
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if (page_has_private(page)) {
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if (try_to_free_buffers(page)) {
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ClearPageDirty(page);
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printk("%s: orphaned page\n", __func__);
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@ -727,7 +727,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
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* process address space (page_count == 1) it can be freed.
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* Otherwise, leave the page on the LRU so it is swappable.
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*/
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if (PagePrivate(page)) {
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if (page_has_private(page)) {
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if (!try_to_release_page(page, sc->gfp_mask))
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goto activate_locked;
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if (!mapping && page_count(page) == 1) {
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