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authorHugh Dickins <hugh.dickins@tiscali.co.uk>2009-12-14 17:58:47 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-12-15 08:53:16 -0800
commitaaa468653b4a0d11c603c48d716f765177a5a9e4 (patch)
tree3cb8c9232dd405001fa38d5519937c5e6c6f32ab /include
parent570a335b8e22579e2a51a68136d2b1f907a20eec (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.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 389e7bd92cca..ac43d87b89b0 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;