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authorFrederic Weisbecker <fweisbec@gmail.com>2012-05-29 15:07:03 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-29 16:22:27 -0700
commit2bb2ba9d51a8044a71a29608d2c4ef8f5b2d57a2 (patch)
tree5e58869c606c541d41a9bfa62aa6e8bc42cae5ac /include
parentf9be23d6da035241b7687b25e64401171986dcef (diff)
downloadlinux-2bb2ba9d51a8044a71a29608d2c4ef8f5b2d57a2.tar.gz
rescounters: add res_counter_uncharge_until()
When killing a res_counter which is a child of other counter, we need to
do

	res_counter_uncharge(child, xxx)
	res_counter_charge(parent, xxx)

This is not atomic and wastes CPU.  This patch adds
res_counter_uncharge_until().  This function's uncharge propagates to
ancestors until specified res_counter.

	res_counter_uncharge_until(child, parent, xxx)

Now the operation is atomic and efficient.

Signed-off-by: Frederic Weisbecker <fweisbec@redhat.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ying Han <yinghan@google.com>
Cc: Glauber Costa <glommer@parallels.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/res_counter.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index fb201896a8b0..5de7a146ead9 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -135,6 +135,9 @@ int __must_check res_counter_charge_nofail(struct res_counter *counter,
 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
 void res_counter_uncharge(struct res_counter *counter, unsigned long val);
 
+void res_counter_uncharge_until(struct res_counter *counter,
+				struct res_counter *top,
+				unsigned long val);
 /**
  * res_counter_margin - calculate chargeable space of a counter
  * @cnt: the counter