rescounters: add res_counter_uncharge_until()
authorFrederic Weisbecker <fweisbec@gmail.com>
Tue, 29 May 2012 22:07:03 +0000 (15:07 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 29 May 2012 23:22:27 +0000 (16:22 -0700)
commit2bb2ba9d51a8044a71a29608d2c4ef8f5b2d57a2
tree5e58869c606c541d41a9bfa62aa6e8bc42cae5ac
parentf9be23d6da035241b7687b25e64401171986dcef
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>
Documentation/cgroups/resource_counter.txt
include/linux/res_counter.h
kernel/res_counter.c