[RESEND, PATCH] memcg: make threshold index in the right position
From: Sha Zhengju <hidden>
Date: 2012-03-12 07:57:19
Also in:
linux-mm
Subsystem:
control group - memory resource controller (memcg), memory management, the rest · Maintainers:
Johannes Weiner, Michal Hocko, Roman Gushchin, Shakeel Butt, Andrew Morton, Linus Torvalds
From: Sha Zhengju <redacted>
Index current_threshold may point to threshold that just equal to
usage after last call of __mem_cgroup_threshold. But after registering
or unregistering 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 <redacted>
Acked-by: KAMEZAWA Hiroyuki <redacted>
Reviewed-by: Kirill A. Shutemov <redacted>
---
mm/memcontrol.c | 11 ++++++-----
1 files changed, 6 insertions(+), 5 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 22d94f5..34737b7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c@@ -183,7 +183,7 @@ 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;
@@ -4193,7 +4193,7 @@ 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(). */
@@ -4319,14 +4319,15 @@ 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 */
@@ -4398,7 +4399,7 @@ 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
--
1.7.4.1