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| 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 /ipc | |
| parent | ba9ddf49391645e6bb93219131a40446538a5e76 (diff) | |
| download | lwn-89e004ea55abe201b29e2d6e35124101f1288ef7.tar.gz lwn-89e004ea55abe201b29e2d6e35124101f1288ef7.zip | |
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 'ipc')
| -rw-r--r-- | ipc/shm.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/ipc/shm.c b/ipc/shm.c index e77ec698cf40..0add3fa5f547 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -737,6 +737,10 @@ asmlinkage long sys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf) case SHM_LOCK: case SHM_UNLOCK: { + struct file *uninitialized_var(shm_file); + + lru_add_drain_all(); /* drain pagevecs to lru lists */ + shp = shm_lock_check(ns, shmid); if (IS_ERR(shp)) { err = PTR_ERR(shp); |