From 323b36197475a97208fde2ae8cf541f3f63f17b7 Mon Sep 17 00:00:00 2001 From: Sha Zhengju Date: Fri, 13 Apr 2012 08:52:08 +1000 Subject: [PATCH] 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 Acked-by: KAMEZAWA Hiroyuki Reviewed-by: Kirill A. Shutemov Cc: Michal Hocko Signed-off-by: Andrew Morton --- mm/memcontrol.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index b7b21f6ee9ea..d564f1d2567c 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; @@ -4267,7 +4267,7 @@ 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(). */ @@ -4393,14 +4393,15 @@ 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 */ -- 2.39.5