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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2009-01-07 18:08:23 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-08 08:31:08 -0800
commit2733c06ac864ed40b9dfbbd5270f3f16949bd4a1 (patch)
tree4847ad04739d6a25dede0e0329295c15cbb79dda /mm/memcontrol.c
parente72e2bd6747c7a5c432197b6614cf3a387e61a0e (diff)
downloadlwn-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.c18
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: