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| author |   Hugh Dickins <hugh@veritas.com> | 2009-01-06 14:39:34 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-06 15:59:03 -0800 |
| commit | 7b1fe59793e61f826bef053107b57b23954833bb (patch) | |
| tree | 0ac769c48123c5d0770b0a0f88bad9e6318b83ed /include | |
| parent | mm: wp lock page before deciding cow (diff) | |
| download | linux-dev-7b1fe59793e61f826bef053107b57b23954833bb.tar.xz linux-dev-7b1fe59793e61f826bef053107b57b23954833bb.zip | |
mm: reuse_swap_page replaces can_share_swap_page
A good place to free up old swap is where do_wp_page(), or do_swap_page(),
is about to redirty the page: the data on disk is then stale and won't be
read again; and if we do decide to write the page out later, using the
previous swap location makes an unnecessary disk seek very likely.
So give can_share_swap_page() the side-effect of delete_from_swap_cache()
when it safely can. And can_share_swap_page() was always a misleading
name, the more so if it has a side-effect: rename it reuse_swap_page().
Irrelevant cleanup nearby: remove swap_token_default_timeout definition
from swap.h: it's used nowhere.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/swap.h | 6 |
1 files changed, 2 insertions, 4 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index 48f309dc5a0c..366556c5b148 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -304,7 +304,7 @@ extern unsigned int count_swap_pages(int, int); extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t); extern sector_t swapdev_block(int, pgoff_t); extern struct swap_info_struct *get_swap_info_struct(unsigned); -extern int can_share_swap_page(struct page *); +extern int reuse_swap_page(struct page *); extern int remove_exclusive_swap_page(struct page *); extern int remove_exclusive_swap_page_ref(struct page *); struct backing_dev_info; @@ -372,8 +372,6 @@ static inline struct page *lookup_swap_cache(swp_entry_t swp) return NULL; } -#define can_share_swap_page(p) (page_mapcount(p) == 1) - static inline int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask) { @@ -388,7 +386,7 @@ static inline void delete_from_swap_cache(struct page *page) { } -#define swap_token_default_timeout 0 +#define reuse_swap_page(page) (page_mapcount(page) == 1) static inline int remove_exclusive_swap_page(struct page *p) { |