Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757260AbZGHPia (ORCPT ); Wed, 8 Jul 2009 11:38:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756665AbZGHPiM (ORCPT ); Wed, 8 Jul 2009 11:38:12 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:33454 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756172AbZGHPiK (ORCPT ); Wed, 8 Jul 2009 11:38:10 -0400 Subject: [PATCH] sched_rt: fix overload bug on rt group scheduling -v2 From: Peter Zijlstra To: Gregory Haskins Cc: Ingo Molnar , Steven Rostedt , LKML , Thomas Gleixner , zengzm.kernel@gmail.com In-Reply-To: <49D49FB6.3000101@novell.com> References: <1238604015.8530.3666.camel@twins> <49D40DBF.8030507@novell.com> <1238654901.8530.5373.camel@twins> <49D49FB6.3000101@novell.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Wed, 08 Jul 2009 17:37:56 +0200 Message-Id: <1247067476.9777.57.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2902 Lines: 97 Greg, how's this? --- Subject: sched_rt: fix overload bug on rt group scheduling From: Peter Zijlstra Date: Wed, 01 Apr 2009 18:40:15 +0200 Fixes an easily triggerable BUG() when setting process affinities. Make sure to count the number of migratable tasks in the same place: the root rt_rq. Otherwise the number doesn't make sense and we'll hit the BUG in set_cpus_allowed_rt(). Also, make sure we only count tasks, not groups (this is probably already taken care of by the fact that rt_se->nr_cpus_allowed will be 0 for groups, but be more explicit) Signed-off-by: Peter Zijlstra --- kernel/sched_rt.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) Index: linux-2.6/kernel/sched_rt.c =================================================================== --- linux-2.6.orig/kernel/sched_rt.c +++ linux-2.6/kernel/sched_rt.c @@ -10,6 +10,8 @@ static inline struct task_struct *rt_tas #ifdef CONFIG_RT_GROUP_SCHED +#define rt_entity_is_task(rt_se) (!(rt_se)->my_q) + static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) { return rt_rq->rq; @@ -22,6 +24,8 @@ static inline struct rt_rq *rt_rq_of_se( #else /* CONFIG_RT_GROUP_SCHED */ +#define rt_entity_is_task(rt_se) (1) + static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) { return container_of(rt_rq, struct rq, rt); @@ -73,7 +77,7 @@ static inline void rt_clear_overload(str static void update_rt_migration(struct rt_rq *rt_rq) { - if (rt_rq->rt_nr_migratory && (rt_rq->rt_nr_running > 1)) { + if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) { if (!rt_rq->overloaded) { rt_set_overload(rq_of_rt_rq(rt_rq)); rt_rq->overloaded = 1; @@ -86,6 +90,12 @@ static void update_rt_migration(struct r static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { + if (!rt_entity_is_task(rt_se)) + return; + + rt_rq = &rq_of_rt_rq(rt_rq)->rt; + + rt_rq->rt_nr_total++; if (rt_se->nr_cpus_allowed > 1) rt_rq->rt_nr_migratory++; @@ -94,6 +104,12 @@ static void inc_rt_migration(struct sche static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { + if (!rt_entity_is_task(rt_se)) + return; + + rt_rq = &rq_of_rt_rq(rt_rq)->rt; + + rt_rq->rt_nr_total--; if (rt_se->nr_cpus_allowed > 1) rt_rq->rt_nr_migratory--; diff --git a/kernel/sched.c b/kernel/sched.c index fd3ac58..a07d520 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -493,6 +493,7 @@ struct rt_rq { #endif #ifdef CONFIG_SMP unsigned long rt_nr_migratory; + unsigned long rt_nr_total; int overloaded; struct plist_head pushable_tasks; #endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/