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linux-kernel: [PATCH 14/27] FS-Cache: Recruit a couple of page f

[PATCH 14/27] FS-Cache: Recruit a couple of page flags for cache management

From: David Howells <dhowells_at_nospam>
Date: Wed Jan 23 2008 - 00:45:00 GMT
To: Trond.Myklebust@netapp.com


Recruit a couple of page flags to aid in cache management. The following extra flags are defined:

 (1) PG_fscache (PG_private_2) The marked page is backed by a local cache and is pinning resources in the cache driver.

 (2) PG_fscache_write (PG_owner_priv_2) The marked page is being written to the local cache. The page may not be modified whilst this is in progress.

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> --- fs/splice.c | 2 +- include/linux/page-flags.h | 39 +++++++++++++++++++++++++++++++++++++-- include/linux/pagemap.h | 11 +++++++++++ mm/filemap.c | 16 ++++++++++++++++ mm/migrate.c | 2 +- mm/page_alloc.c | 3 +++ mm/readahead.c | 9 +++++---- mm/swap.c | 4 ++-- mm/swap_state.c | 4 ++-- mm/truncate.c | 10 +++++----- mm/vmscan.c | 2 +- 11 files changed, 84 insertions(+), 18 deletions(-) diff --git a/fs/splice.c b/fs/splice.c index 6bdcb61..61edad7 100644 --- a/fs/splice.c +++ b/fs/splice.c
@@ -58,7 +58,7 @@ static int page_cache_pipe_buf_steal(struct pipe_inode_info *pipe,
*/ wait_on_page_writeback(page); - if (PagePrivate(page)) + if (page_has_private(page)) try_to_release_page(page, GFP_KERNEL); /* diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 209d3a4..f375e3b 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h
@@ -77,25 +77,32 @@
#define PG_active 6 #define PG_slab 7 /* slab debug (Suparna wants this) */ -#define PG_owner_priv_1 8 /* Owner use. If pagecache, fs may use*/ +#define PG_owner_priv_1 8 /* Owner use. fs may use in pagecache */ #define PG_arch_1 9 #define PG_reserved 10 #define PG_private 11 /* If pagecache, has fs-private data */ #define PG_writeback 12 /* Page is under writeback */ +#define PG_private_2 13 /* If pagecache, has fs aux data */ #define PG_compound 14 /* Part of a compound page */ #define PG_swapcache 15 /* Swap page: swp_entry_t in private */ #define PG_mappedtodisk 16 /* Has blocks allocated on-disk */ #define PG_reclaim 17 /* To be reclaimed asap */ +#define PG_owner_priv_2 18 /* Owner use. fs may use in pagecache */ #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 */ +/* PG_owner_priv_1/2 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 PG_fscache_write PG_owner_priv_2 /* Writing to local cache */ + +/* PG_private_2 causes releasepage() and co to be invoked */ +#define PG_fscache PG_private_2 /* Backed by local cache */ + #if (BITS_PER_LONG > 32) /*
@@ -199,6 +206,23 @@ static inline void SetPageUptodate(struct page *page)
#define TestClearPageWriteback(page) test_and_clear_bit(PG_writeback, \ &(page)->flags) +#define PagePrivate2(page) test_bit(PG_private_2, &(page)->flags) +#define SetPagePrivate2(page) set_bit(PG_private_2, &(page)->flags) +#define ClearPagePrivate2(page) clear_bit(PG_private_2, &(page)->flags) +#define TestSetPagePrivate2(page) test_and_set_bit(PG_private_2, &(page)->flags) +#define TestClearPagePrivate2(page) test_and_clear_bit(PG_private_2, \ + &(page)->flags) + +#define PageOwnerPriv2(page) test_bit(PG_owner_priv_2, \ + &(page)->flags) +#define SetPageOwnerPriv2(page) set_bit(PG_owner_priv_2, &(page)->flags) +#define ClearPageOwnerPriv2(page) clear_bit(PG_owner_priv_2, \ + &(page)->flags) +#define TestSetPageOwnerPriv2(page) test_and_set_bit(PG_owner_priv_2, \ + &(page)->flags) +#define TestClearPageOwnerPriv2(page) test_and_clear_bit(PG_owner_priv_2, \ + &(page)->flags) + #define PageBuddy(page) test_bit(PG_buddy, &(page)->flags) #define __SetPageBuddy(page) __set_bit(PG_buddy, &(page)->flags) #define __ClearPageBuddy(page) __clear_bit(PG_buddy, &(page)->flags)
@@ -272,4 +296,15 @@ static inline void set_page_writeback(struct page *page)
test_set_page_writeback(page); } +/** + * 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 */ diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index db8a410..f9e0f81 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h
@@ -212,6 +212,17 @@ static inline void wait_on_page_writeback(struct page *page)
extern void end_page_writeback(struct page *page); /* + * Wait for a PG_private_2 to become clear + */ +static inline void wait_on_page_owner_priv_2(struct page *page) +{ + if (PagePrivate2(page)) + wait_on_page_bit(page, PG_private_2); +} + +extern void end_page_owner_priv_2(struct page *page); + +/* * Fault a userspace page into pagetables. Return non-zero on a fault. * * This assumes that two userspace pages are always sufficient. That's diff --git a/mm/filemap.c b/mm/filemap.c index f4d0cde..f22801a 100644 --- a/mm/filemap.c +++ b/mm/filemap.c
@@ -572,6 +572,19 @@ void end_page_writeback(struct page *page)
EXPORT_SYMBOL(end_page_writeback); /** + * end_page_own - End writing page to cache + * @page: the page + */ +void end_page_owner_priv_2(struct page *page) +{ + if (!TestClearPageOwnerPriv2(page)) + BUG(); + smp_mb__after_clear_bit(); + wake_up_page(page, PG_owner_priv_2); +} +EXPORT_SYMBOL(end_page_owner_priv_2); + +/** * __lock_page - get a lock on the page, assuming we need to sleep to get it * @page: the page to lock *
@@ -2540,6 +2553,9 @@ out:
* (presumably at page->private). If the release was successful, return `1'. * Otherwise return zero. * + * This may also be called if PG_fscache is set on a page, indicating that the + * page is known to the local caching routines. + * * The @gfp_mask argument specifies whether I/O may be performed to release * this page (__GFP_IO), and whether the call may block (__GFP_WAIT). * diff --git a/mm/migrate.c b/mm/migrate.c index 3fa4b4a..0778cce 100644 --- a/mm/migrate.c +++ b/mm/migrate.c
@@ -545,7 +545,7 @@ static int fallback_migrate_page(struct address_space *mapping,
* Buffers may be managed in a filesystem specific way. * We must have no buffers or drop them. */ - if (PagePrivate(page) && + if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) return -EAGAIN; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index b2838c2..55b47da 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c
@@ -230,6 +230,7 @@ static void bad_page(struct page *page)
dump_stack(); page->flags &= ~(1 << PG_lru | 1 << PG_private | + 1 << PG_fscache | 1 << PG_locked | 1 << PG_active | 1 << PG_dirty |
@@ -456,6 +457,7 @@ static inline int free_pages_check(struct page *page)
(page->flags & ( 1 << PG_lru | 1 << PG_private | + 1 << PG_fscache | 1 << PG_locked | 1 << PG_active | 1 << PG_slab |
@@ -605,6 +607,7 @@ static int prep_new_page(struct page *page, int order, gfp_t gfp_flags)
(page->flags & ( 1 << PG_lru | 1 << PG_private | + 1 << PG_fscache | 1 << PG_locked | 1 << PG_active | 1 << PG_dirty | diff --git a/mm/readahead.c b/mm/readahead.c index 75aa6b6..272ffc7 100644 --- a/mm/readahead.c +++ b/mm/readahead.c
@@ -46,14 +46,15 @@ EXPORT_SYMBOL_GPL(file_ra_state_init);
/* * see if a page needs releasing upon read_cache_pages() failure - * - the caller of read_cache_pages() may have set PG_private before calling, - * such as the NFS fs marking pages that are cached locally on disk, thus we - * need to give the fs a chance to clean up in the event of an error + * - the caller of read_cache_pages() may have set PG_private or PG_fscache + * before calling, such as the NFS fs marking pages that are cached locally + * on disk, thus we need to give the fs a chance to clean up in the event of + * an error */ static void read_cache_pages_invalidate_page(struct address_space *mapping, struct page *page) { - if (PagePrivate(page)) { + if (page_has_private(page)) { if (TestSetPageLocked(page)) BUG(); page->mapping = mapping; diff --git a/mm/swap.c b/mm/swap.c index 9ac8832..22d6e03 100644 --- a/mm/swap.c +++ b/mm/swap.c
@@ -455,8 +455,8 @@ void pagevec_strip(struct pagevec *pvec)
for (i = 0; i < pagevec_count(pvec); i++) { struct page *page = pvec->pages[i]; - if (PagePrivate(page) && !TestSetPageLocked(page)) { - if (PagePrivate(page)) + if (page_has_private(page) && !TestSetPageLocked(page)) { + if (page_has_private(page)) try_to_release_page(page, 0); unlock_page(page); } diff --git a/mm/swap_state.c b/mm/swap_state.c index b526356..33f1e5c 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c
@@ -76,7 +76,7 @@ static int __add_to_swap_cache(struct page *page, swp_entry_t entry,
BUG_ON(!PageLocked(page)); BUG_ON(PageSwapCache(page)); - BUG_ON(PagePrivate(page)); + BUG_ON(page_has_private(page)); error = radix_tree_preload(gfp_mask); if (!error) { write_lock_irq(&swapper_space.tree_lock);
@@ -129,7 +129,7 @@ void __delete_from_swap_cache(struct page *page)
BUG_ON(!PageLocked(page)); BUG_ON(!PageSwapCache(page)); BUG_ON(PageWriteback(page)); - BUG_ON(PagePrivate(page)); + BUG_ON(page_has_private(page)); radix_tree_delete(&swapper_space.page_tree, page_private(page)); set_page_private(page, 0); diff --git a/mm/truncate.c b/mm/truncate.c index cadc156..5b7d1c5 100644 --- a/mm/truncate.c +++ b/mm/truncate.c
@@ -49,7 +49,7 @@ void do_invalidatepage(struct page *page, unsigned long offset)
static inline void truncate_partial_page(struct page *page, unsigned partial) { zero_user_page(page, partial, PAGE_CACHE_SIZE - partial, KM_USER0); - if (PagePrivate(page)) + if (page_has_private(page)) do_invalidatepage(page, partial); }
@@ -100,7 +100,7 @@ truncate_complete_page(struct address_space *mapping, struct page *page)
cancel_dirty_page(page, PAGE_CACHE_SIZE); - if (PagePrivate(page)) + if (page_has_private(page)) do_invalidatepage(page, 0); remove_from_page_cache(page);
@@ -125,7 +125,7 @@ invalidate_complete_page(struct address_space *mapping, struct page *page)
if (page->mapping != mapping) return 0; - if (PagePrivate(page) && !try_to_release_page(page, 0)) + if (page_has_private(page) && !try_to_release_page(page, 0)) return 0; ret = remove_mapping(mapping, page);
@@ -347,14 +347,14 @@ invalidate_complete_page2(struct address_space *mapping, struct page *page)
if (page->mapping != mapping) return 0; - if (PagePrivate(page) && !try_to_release_page(page, GFP_KERNEL)) + if (page_has_private(page) && !try_to_release_page(page, GFP_KERNEL)) return 0; write_lock_irq(&mapping->tree_lock); if (PageDirty(page)) goto failed; - BUG_ON(PagePrivate(page)); + BUG_ON(page_has_private(page)); __remove_from_page_cache(page); write_unlock_irq(&mapping->tree_lock); ClearPageUptodate(page); diff --git a/mm/vmscan.c b/mm/vmscan.c index e5a9597..ff2fa2d 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c
@@ -578,7 +578,7 @@ static unsigned long shrink_page_list(struct list_head *page_list,
* process address space (page_count == 1) it can be freed. * Otherwise, leave the page on the LRU so it is swappable. */ - if (PagePrivate(page)) { + if (page_has_private(page)) { if (!try_to_release_page(page, sc->gfp_mask)) goto activate_locked; if (!mapping && page_count(page) == 1) - To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html