From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932591Ab1ESGJL (ORCPT ); Thu, 19 May 2011 02:09:11 -0400 Received: from fgwmail6.fujitsu.co.jp ([192.51.44.36]:41996 "EHLO fgwmail6.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932267Ab1ESGJJ (ORCPT ); Thu, 19 May 2011 02:09:09 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Message-ID: <4DD4B3FA.5060901@jp.fujitsu.com> Date: Thu, 19 May 2011 15:08:58 +0900 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; ja; rv:1.9.2.17) Gecko/20110414 Lightning/1.0b2 Thunderbird/3.1.10 MIME-Version: 1.0 To: yong.zhang0@gmail.com CC: paulmck@linux.vnet.ibm.com, a.p.zijlstra@chello.nl, oleg@redhat.com, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, mingo@elte.hu, lizf@cn.fujitsu.com, miaox@cn.fujitsu.com Subject: [PATCH v2 2/2] cpuset: fix cpuset_cpus_allowed_fallback() don't update tsk->rt.nr_cpus_allowed References: <20110428161149.GA15658@redhat.com> <20110502194416.2D61.A69D9226@jp.fujitsu.com> <20110502195657.2D68.A69D9226@jp.fujitsu.com> <1305129929.2914.247.camel@laptop> <4DCCC61F.80408@jp.fujitsu.com> <20110515185547.GL2258@linux.vnet.ibm.com> <20110516132623.GA2058@zhy> <4DD4B358.3080705@jp.fujitsu.com> In-Reply-To: <4DD4B358.3080705@jp.fujitsu.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The rule is, we have to update tsk->rt.nr_cpus_allowed if we change tsk->cpus_allowed. Otherwise RT scheduler may confuse. This patch fixes it. Signed-off-by: KOSAKI Motohiro Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Ingo Molnar --- include/linux/cpuset.h | 2 +- include/linux/sched.h | 7 +++++++ kernel/cpuset.c | 4 ++-- kernel/kthread.c | 4 ++-- kernel/sched.c | 19 ++++++++++++------- 5 files changed, 24 insertions(+), 12 deletions(-) diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h index f20eb8f..e9eaec5 100644 --- a/include/linux/cpuset.h +++ b/include/linux/cpuset.h @@ -146,7 +146,7 @@ static inline void cpuset_cpus_allowed(struct task_struct *p, static inline int cpuset_cpus_allowed_fallback(struct task_struct *p) { - cpumask_copy(&p->cpus_allowed, cpu_possible_mask); + do_set_cpus_allowed(p, cpu_possible_mask); return cpumask_any(cpu_active_mask); } diff --git a/include/linux/sched.h b/include/linux/sched.h index 12211e1..fa8fe23 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1799,9 +1799,16 @@ static inline void rcu_copy_process(struct task_struct *p) #endif #ifdef CONFIG_SMP +extern void do_set_cpus_allowed(struct task_struct *p, + const struct cpumask *new_mask); + extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask); #else +static inline void do_set_cpus_allowed(struct task_struct *p, + const struct cpumask *new_mask) +{ +} static inline int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) { diff --git a/kernel/cpuset.c b/kernel/cpuset.c index 2bb8c2e..04ceb53 100644 --- a/kernel/cpuset.c +++ b/kernel/cpuset.c @@ -2195,7 +2195,7 @@ int cpuset_cpus_allowed_fallback(struct task_struct *tsk) rcu_read_lock(); cs = task_cs(tsk); if (cs) - cpumask_copy(&tsk->cpus_allowed, cs->cpus_allowed); + do_set_cpus_allowed(tsk, cs->cpus_allowed); rcu_read_unlock(); /* @@ -2222,7 +2222,7 @@ int cpuset_cpus_allowed_fallback(struct task_struct *tsk) * Like above we can temporary set any mask and rely on * set_cpus_allowed_ptr() as synchronization point. */ - cpumask_copy(&tsk->cpus_allowed, cpu_possible_mask); + do_set_cpus_allowed(tsk, cpu_possible_mask); cpu = cpumask_any(cpu_active_mask); } diff --git a/kernel/kthread.c b/kernel/kthread.c index 3b34d27..4ba7ccc 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -202,8 +202,8 @@ void kthread_bind(struct task_struct *p, unsigned int cpu) return; } - p->cpus_allowed = cpumask_of_cpu(cpu); - p->rt.nr_cpus_allowed = 1; + /* It's safe because the task is inactive. */ + do_set_cpus_allowed(p, cpumask_of(cpu)); p->flags |= PF_THREAD_BOUND; } EXPORT_SYMBOL(kthread_bind); diff --git a/kernel/sched.c b/kernel/sched.c index 8efe3b7..52f1b5b 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -5826,7 +5826,7 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu) idle->state = TASK_RUNNING; idle->se.exec_start = sched_clock(); - cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu)); + do_set_cpus_allowed(idle, cpumask_of(cpu)); /* * We're having a chicken and egg problem, even though we are * holding rq->lock, the cpu isn't yet set to this cpu so the @@ -5914,6 +5914,16 @@ static inline void sched_init_granularity(void) } #ifdef CONFIG_SMP +void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) +{ + if (p->sched_class && p->sched_class->set_cpus_allowed) + p->sched_class->set_cpus_allowed(p, new_mask); + else { + cpumask_copy(&p->cpus_allowed, new_mask); + p->rt.nr_cpus_allowed = cpumask_weight(new_mask); + } +} + /* * This is how migration works: * @@ -5959,12 +5969,7 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) goto out; } - if (p->sched_class->set_cpus_allowed) - p->sched_class->set_cpus_allowed(p, new_mask); - else { - cpumask_copy(&p->cpus_allowed, new_mask); - p->rt.nr_cpus_allowed = cpumask_weight(new_mask); - } + do_set_cpus_allowed(p, new_mask); /* Can the task run on the task's current CPU? If so, we're done */ if (cpumask_test_cpu(task_cpu(p), new_mask)) -- 1.7.3.1