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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
parentf9be23d6da035241b7687b25e64401171986dcef (diff)
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>
-rw-r--r--Documentation/cgroups/resource_counter.txt8
-rw-r--r--include/linux/res_counter.h3
-rw-r--r--kernel/res_counter.c10
3 files changed, 19 insertions, 2 deletions
diff --git a/Documentation/cgroups/resource_counter.txt b/Documentation/cgroups/resource_counter.txt
index f3c4ec3626a..0c4a344e78f 100644
--- a/Documentation/cgroups/resource_counter.txt
+++ b/Documentation/cgroups/resource_counter.txt
@@ -92,6 +92,14 @@ to work with it.
The _locked routines imply that the res_counter->lock is taken.
+ f. void res_counter_uncharge_until
+ (struct res_counter *rc, struct res_counter *top,
+ unsinged long val)
+
+ Almost same as res_cunter_uncharge() but propagation of uncharge
+ stops when rc == top. This is useful when kill a res_coutner in
+ child cgroup.
+
2.1 Other accounting routines
There are more routines that may help you with common needs, like
diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index fb201896a8b..5de7a146ead 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
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index bebe2b170d4..ad581aa2369 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -94,13 +94,15 @@ void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
counter->usage -= 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)
{
unsigned long flags;
struct res_counter *c;
local_irq_save(flags);
- for (c = counter; c != NULL; c = c->parent) {
+ for (c = counter; c != top; c = c->parent) {
spin_lock(&c->lock);
res_counter_uncharge_locked(c, val);
spin_unlock(&c->lock);
@@ -108,6 +110,10 @@ void res_counter_uncharge(struct res_counter *counter, unsigned long val)
local_irq_restore(flags);
}
+void res_counter_uncharge(struct res_counter *counter, unsigned long val)
+{
+ res_counter_uncharge_until(counter, NULL, val);
+}
static inline unsigned long long *
res_counter_member(struct res_counter *counter, int member)