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From: Frederic Weisbecker <fweisbec@gmail.com>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
	Paul Menage <paul@paulmenage.org>, Li Zefan <lizf@cn.fujitsu.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Aditya Kali <adityakali@google.com>,
	Oleg Nesterov <oleg@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Kay Sievers <kay.sievers@vrfy.org>,
	Tim Hockin <thockin@hockin.org>, Tejun Heo <tj@kernel.org>
Subject: [PATCH 05/12] cgroups: Ability to stop res charge propagation on bounded ancestor
Date: Tue,  6 Sep 2011 02:12:59 +0200	[thread overview]
Message-ID: <1315267986-28937-6-git-send-email-fweisbec@gmail.com> (raw)
In-Reply-To: <1315267986-28937-1-git-send-email-fweisbec@gmail.com>

Moving a task from a cgroup to another may require to substract
its resource charge from the old cgroup and add it to the new one.

For this to happen, the uncharge/charge propagation can just stop
when we reach the common ancestor for the two cgroups. Further
the performance reasons, we also want to avoid to temporarily
overload the common ancestors with a non-accurate resource
counter usage if we charge first the new cgroup and uncharge the
old one thereafter. This is going to be a requirement for the coming
max number of task subsystem.

To solve this, provide a pair of new API that can charge/uncharge
a resource counter until we reach a given ancestor.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul Menage <paul@paulmenage.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Aditya Kali <adityakali@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Tim Hockin <thockin@hockin.org>
Cc: Tejun Heo <tj@kernel.org>
---
 include/linux/res_counter.h |   19 ++++++++++++++++---
 kernel/res_counter.c        |   13 ++++++++-----
 2 files changed, 24 insertions(+), 8 deletions(-)

diff --git a/include/linux/res_counter.h b/include/linux/res_counter.h
index 109d118..95e7756 100644
--- a/include/linux/res_counter.h
+++ b/include/linux/res_counter.h
@@ -117,8 +117,16 @@ void res_counter_init(struct res_counter *counter, struct res_counter *parent);
 
 int __must_check res_counter_charge_locked(struct res_counter *counter,
 		unsigned long val);
-int __must_check res_counter_charge(struct res_counter *counter,
-		unsigned long val, struct res_counter **limit_fail_at);
+int __must_check res_counter_charge_until(struct res_counter *counter,
+					  struct res_counter *limit,
+					  unsigned long val,
+					  struct res_counter **limit_fail_at);
+static inline int __must_check
+res_counter_charge(struct res_counter *counter, unsigned long val,
+		   struct res_counter **limit_fail_at)
+{
+	return res_counter_charge_until(counter, NULL, val, limit_fail_at);
+}
 
 /*
  * uncharge - tell that some portion of the resource is released
@@ -131,7 +139,12 @@ int __must_check res_counter_charge(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 *limit,
+				unsigned long val);
+static inline void res_counter_uncharge(struct res_counter *counter, unsigned long val)
+{
+	res_counter_uncharge_until(counter, NULL, val);
+}
 
 /**
  * res_counter_margin - calculate chargeable space of a counter
diff --git a/kernel/res_counter.c b/kernel/res_counter.c
index 1349115..1185c86 100644
--- a/kernel/res_counter.c
+++ b/kernel/res_counter.c
@@ -35,8 +35,9 @@ int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
 	return 0;
 }
 
-int res_counter_charge(struct res_counter *counter, unsigned long val,
-			struct res_counter **limit_fail_at)
+int res_counter_charge_until(struct res_counter *counter,
+			     struct res_counter *limit, unsigned long val,
+			     struct res_counter **limit_fail_at)
 {
 	int ret;
 	unsigned long flags;
@@ -44,7 +45,7 @@ int res_counter_charge(struct res_counter *counter, unsigned long val,
 
 	*limit_fail_at = NULL;
 	local_irq_save(flags);
-	for (c = counter; c != NULL; c = c->parent) {
+	for (c = counter; c != limit; c = c->parent) {
 		spin_lock(&c->lock);
 		ret = res_counter_charge_locked(c, val);
 		spin_unlock(&c->lock);
@@ -74,13 +75,15 @@ 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 *limit,
+				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 != limit; c = c->parent) {
 		spin_lock(&c->lock);
 		res_counter_uncharge_locked(c, val);
 		spin_unlock(&c->lock);
-- 
1.7.5.4


  parent reply	other threads:[~2011-09-06  0:14 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-09-06  0:12 [PATCH 00/12 v4][RESEND] cgroups: Task counter subsystem Frederic Weisbecker
2011-09-06  0:12 ` [PATCH 01/12] cgroups: Add res_counter_write_u64() API Frederic Weisbecker
2011-09-06  0:12 ` [PATCH 02/12] cgroups: New resource counter inheritance API Frederic Weisbecker
2011-09-06 22:17   ` Andrew Morton
2011-09-08 13:25     ` Frederic Weisbecker
2011-09-06  0:12 ` [PATCH 03/12] cgroups: Add previous cgroup in can_attach_task/attach_task callbacks Frederic Weisbecker
2011-09-06  0:12 ` [PATCH 04/12] cgroups: New cancel_attach_task subsystem callback Frederic Weisbecker
2011-09-06  0:12 ` Frederic Weisbecker [this message]
2011-09-06  0:13 ` [PATCH 06/12] cgroups: Add res counter common ancestor searching Frederic Weisbecker
2011-09-06 22:21   ` Andrew Morton
2011-09-09 12:31     ` Frederic Weisbecker
2011-09-06  0:13 ` [PATCH 07/12] res_counter: Allow charge failure pointer to be null Frederic Weisbecker
2011-09-06  0:13 ` [PATCH 08/12] cgroups: Pull up res counter charge failure interpretation to caller Frederic Weisbecker
2011-09-06 22:26   ` Andrew Morton
2011-09-09 13:33     ` Frederic Weisbecker
2011-09-09 15:17       ` Andrew Morton
2011-09-06  0:13 ` [PATCH 09/12] cgroups: Add a task counter subsystem Frederic Weisbecker
2011-09-06 22:40   ` Andrew Morton
2011-09-13 15:13     ` Frederic Weisbecker
2011-09-06  0:13 ` [PATCH 10/12] cgroups: Add documentation for " Frederic Weisbecker
2011-09-06 22:41   ` Andrew Morton
2011-09-13 17:35     ` Frederic Weisbecker
2011-09-06  0:13 ` [RFC PATCH 11/12] cgroups: Allow subsystems to cancel a fork Frederic Weisbecker
2011-09-15 21:09   ` Andrew Morton
2011-10-01 15:29     ` Frederic Weisbecker
2011-09-06  0:13 ` [RFC PATCH 12/12] cgroups: Convert task counter to use the subsys fork callback Frederic Weisbecker

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