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authorSha Zhengju <handai.szj@taobao.com>2012-05-29 15:06:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-29 16:22:25 -0700
commit748dad36d645f5c4517a115d60bb3a0e8f877ac0 (patch)
tree0f3206a06c3d58b922535957083d5216467eddb9
parenta0db00fcf5da79911b7ff2db63ea7c0a5711e096 (diff)
memcg: make threshold index in the right position
Index current_threshold may point to threshold that just equal to usage after last call of __mem_cgroup_threshold. But after registering a new event, it will change (pointing to threshold just below usage). So make it consistent here. For example: now: threshold array: 3 [5] 7 9 (usage = 6, [index] = 5) next turn (after calling __mem_cgroup_threshold): threshold array: 3 5 [7] 9 (usage = 7, [index] = 7) after registering a new event (threshold = 10): threshold array: 3 [5] 7 9 10 (usage = 7, [index] = 5) Signed-off-by: Sha Zhengju <handai.szj@taobao.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memcontrol.c11
1 files changed, 6 insertions, 5 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 775b94b1b8bd..a8abf919c70a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -181,7 +181,7 @@ struct mem_cgroup_threshold {
/* For threshold */
struct mem_cgroup_threshold_ary {
- /* An array index points to threshold just below usage. */
+ /* An array index points to threshold just below or equal to usage. */
int current_threshold;
/* Size of entries[] */
unsigned int size;
@@ -4280,7 +4280,7 @@ static void __mem_cgroup_threshold(struct mem_cgroup *memcg, bool swap)
usage = mem_cgroup_usage(memcg, swap);
/*
- * current_threshold points to threshold just below usage.
+ * current_threshold points to threshold just below or equal to usage.
* If it's not true, a threshold was crossed after last
* call of __mem_cgroup_threshold().
*/
@@ -4406,14 +4406,15 @@ static int mem_cgroup_usage_register_event(struct cgroup *cgrp,
/* Find current threshold */
new->current_threshold = -1;
for (i = 0; i < size; i++) {
- if (new->entries[i].threshold < usage) {
+ if (new->entries[i].threshold <= usage) {
/*
* new->current_threshold will not be used until
* rcu_assign_pointer(), so it's safe to increment
* it here.
*/
++new->current_threshold;
- }
+ } else
+ break;
}
/* Free old spare buffer and save old primary buffer as spare */
@@ -4482,7 +4483,7 @@ static void mem_cgroup_usage_unregister_event(struct cgroup *cgrp,
continue;
new->entries[j] = thresholds->primary->entries[i];
- if (new->entries[j].threshold < usage) {
+ if (new->entries[j].threshold <= usage) {
/*
* new->current_threshold will not be used
* until rcu_assign_pointer(), so it's safe to increment