diff options
| author | Lee Schermerhorn <Lee.Schermerhorn@hp.com> | 2008-10-18 20:26:43 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-10-20 08:50:26 -0700 |
| commit | 89e004ea55abe201b29e2d6e35124101f1288ef7 (patch) | |
| tree | 272a8f453106fd33d66fd7153f44696648dbe8b6 /include/linux/pagemap.h | |
| parent | ba9ddf49391645e6bb93219131a40446538a5e76 (diff) | |
SHM_LOCKED pages are unevictable
Shmem segments locked into memory via shmctl(SHM_LOCKED) should not be
kept on the normal LRU, since scanning them is a waste of time and might
throw off kswapd's balancing algorithms. Place them on the unevictable
LRU list instead.
Use the AS_UNEVICTABLE flag to mark address_space of SHM_LOCKed shared
memory regions as unevictable. Then these pages will be culled off the
normal LRU lists during vmscan.
Add new wrapper function to clear the mapping's unevictable state when/if
shared memory segment is munlocked.
Add 'scan_mapping_unevictable_page()' to mm/vmscan.c to scan all pages in
the shmem segment's mapping [struct address_space] for evictability now
that they're no longer locked. If so, move them to the appropriate zone
lru list.
Changes depend on [CONFIG_]UNEVICTABLE_LRU.
[kosaki.motohiro@jp.fujitsu.com: revert shm change]
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Kosaki Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/pagemap.h')
| -rw-r--r-- | include/linux/pagemap.h | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 09164d2c5c2..4b6c4d8d26b 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -40,14 +40,20 @@ static inline void mapping_set_unevictable(struct address_space *mapping) set_bit(AS_UNEVICTABLE, &mapping->flags); } +static inline void mapping_clear_unevictable(struct address_space *mapping) +{ + clear_bit(AS_UNEVICTABLE, &mapping->flags); +} + static inline int mapping_unevictable(struct address_space *mapping) { - if (mapping && (mapping->flags & AS_UNEVICTABLE)) - return 1; - return 0; + if (likely(mapping)) + return test_bit(AS_UNEVICTABLE, &mapping->flags); + return !!mapping; } #else static inline void mapping_set_unevictable(struct address_space *mapping) { } +static inline void mapping_clear_unevictable(struct address_space *mapping) { } static inline int mapping_unevictable(struct address_space *mapping) { return 0; |