diff options
| author | Hugh Dickins <hugh.dickins@tiscali.co.uk> | 2009-12-14 17:58:47 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-12-15 08:53:16 -0800 |
| commit | aaa468653b4a0d11c603c48d716f765177a5a9e4 (patch) | |
| tree | 3cb8c9232dd405001fa38d5519937c5e6c6f32ab /include | |
| parent | 570a335b8e22579e2a51a68136d2b1f907a20eec (diff) | |
swap_info: note SWAP_MAP_SHMEM
While we're fiddling with the swap_map values, let's assign a particular
value to shmem/tmpfs swap pages: their swap counts are never incremented,
and it helps swapoff's try_to_unuse() a little if it can immediately
distinguish those pages from process pages.
Since we've no use for SWAP_MAP_BAD | COUNT_CONTINUED,
we might as well use that 0xbf value for SWAP_MAP_SHMEM.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Rik van Riel <riel@redhat.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, 6 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h index 389e7bd92cc..ac43d87b89b 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -157,6 +157,7 @@ enum { #define SWAP_HAS_CACHE 0x40 /* Flag page is cached, in first swap_map */ #define SWAP_CONT_MAX 0x7f /* Max count, in each swap_map continuation */ #define COUNT_CONTINUED 0x80 /* See swap_map continuation for full count */ +#define SWAP_MAP_SHMEM 0xbf /* Owned by shmem/tmpfs, in first swap_map */ /* * The in-memory structure used to track swap areas. @@ -316,6 +317,7 @@ extern swp_entry_t get_swap_page(void); extern swp_entry_t get_swap_page_of_type(int); extern int valid_swaphandles(swp_entry_t, unsigned long *); extern int add_swap_count_continuation(swp_entry_t, gfp_t); +extern void swap_shmem_alloc(swp_entry_t); extern int swap_duplicate(swp_entry_t); extern int swapcache_prepare(swp_entry_t); extern void swap_free(swp_entry_t); @@ -394,6 +396,10 @@ static inline int add_swap_count_continuation(swp_entry_t swp, gfp_t gfp_mask) return 0; } +static inline void swap_shmem_alloc(swp_entry_t swp) +{ +} + static inline int swap_duplicate(swp_entry_t swp) { return 0; |