diff options
| author | KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> | 2009-01-07 18:08:23 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-08 08:31:08 -0800 |
| commit | 2733c06ac864ed40b9dfbbd5270f3f16949bd4a1 (patch) | |
| tree | 4847ad04739d6a25dede0e0329295c15cbb79dda /mm/memcontrol.c | |
| parent | e72e2bd6747c7a5c432197b6614cf3a387e61a0e (diff) | |
| download | lwn-2733c06ac864ed40b9dfbbd5270f3f16949bd4a1.tar.gz lwn-2733c06ac864ed40b9dfbbd5270f3f16949bd4a1.zip | |
memcg: protect prev_priority
Currently, mem_cgroup doesn't have own lock and almost its member doesn't
need. (e.g. mem_cgroup->info is protected by zone lock, mem_cgroup->stat
is per cpu variable)
However, there is one explict exception. mem_cgroup->prev_priorit need
lock, but doesn't protect. Luckly, this is NOT bug because prev_priority
isn't used for current reclaim code.
However, we plan to use prev_priority future again. Therefore, fixing is
better.
In addition, we plan to reuse this lock for another member. Then
"reclaim_param_lock" name is better than "prev_priority_lock".
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: 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 'mm/memcontrol.c')
| -rw-r--r-- | mm/memcontrol.c | 18 |
1 files changed, 17 insertions, 1 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index af28e128b749..027c0dd7a83e 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -144,6 +144,11 @@ struct mem_cgroup { */ struct mem_cgroup_lru_info info; + /* + protect against reclaim related member. + */ + spinlock_t reclaim_param_lock; + int prev_priority; /* for recording reclaim priority */ /* @@ -400,18 +405,28 @@ int mem_cgroup_calc_mapped_ratio(struct mem_cgroup *mem) */ int mem_cgroup_get_reclaim_priority(struct mem_cgroup *mem) { - return mem->prev_priority; + int prev_priority; + + spin_lock(&mem->reclaim_param_lock); + prev_priority = mem->prev_priority; + spin_unlock(&mem->reclaim_param_lock); + + return prev_priority; } void mem_cgroup_note_reclaim_priority(struct mem_cgroup *mem, int priority) { + spin_lock(&mem->reclaim_param_lock); if (priority < mem->prev_priority) mem->prev_priority = priority; + spin_unlock(&mem->reclaim_param_lock); } void mem_cgroup_record_reclaim_priority(struct mem_cgroup *mem, int priority) { + spin_lock(&mem->reclaim_param_lock); mem->prev_priority = priority; + spin_unlock(&mem->reclaim_param_lock); } int mem_cgroup_inactive_anon_is_low(struct mem_cgroup *memcg, struct zone *zone) @@ -2076,6 +2091,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont) } mem_cgroup_set_inactive_ratio(mem); mem->last_scanned_child = NULL; + spin_lock_init(&mem->reclaim_param_lock); return &mem->css; free_out: |