Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755929AbZKCHFV (ORCPT ); Tue, 3 Nov 2009 02:05:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753778AbZKCHFU (ORCPT ); Tue, 3 Nov 2009 02:05:20 -0500 Received: from hera.kernel.org ([140.211.167.34]:39478 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753248AbZKCHFS (ORCPT ); Tue, 3 Nov 2009 02:05:18 -0500 Date: Tue, 3 Nov 2009 07:04:00 GMT From: tip-bot for Mike Galbraith Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, a.p.zijlstra@chello.nl, eparis@redhat.com, efault@gmx.de, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, eparis@redhat.com, a.p.zijlstra@chello.nl, efault@gmx.de, tglx@linutronix.de, mingo@elte.hu In-Reply-To: <1256813310.7574.3.camel@marge.simson.net> References: <1256813310.7574.3.camel@marge.simson.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/urgent] sched: Fix kthread_bind() by moving the body of kthread_bind() to sched.c Message-ID: Git-Commit-ID: b84ff7d6f1b7f8a43414e74d972ec4c8f3361db4 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3934 Lines: 113 Commit-ID: b84ff7d6f1b7f8a43414e74d972ec4c8f3361db4 Gitweb: http://git.kernel.org/tip/b84ff7d6f1b7f8a43414e74d972ec4c8f3361db4 Author: Mike Galbraith AuthorDate: Thu, 29 Oct 2009 11:48:30 +0100 Committer: Ingo Molnar CommitDate: Tue, 3 Nov 2009 07:25:00 +0100 sched: Fix kthread_bind() by moving the body of kthread_bind() to sched.c Eric Paris reported that commit f685ceacab07d3f6c236f04803e2f2f0dbcc5afb causes boot time PREEMPT_DEBUG complaints. [ 4.590699] BUG: using smp_processor_id() in preemptible [00000000] code: rmmod/1314 [ 4.593043] caller is task_hot+0x86/0xd0 Since kthread_bind() messes with scheduler internals, move the body to sched.c, and lock the runqueue. Reported-by: Eric Paris Signed-off-by: Mike Galbraith Tested-by: Eric Paris Cc: Peter Zijlstra LKML-Reference: <1256813310.7574.3.camel@marge.simson.net> [ v2: fix !SMP build and clean up ] Signed-off-by: Ingo Molnar --- kernel/kthread.c | 23 ----------------------- kernel/sched.c | 32 ++++++++++++++++++++++++++++++++ 2 files changed, 32 insertions(+), 23 deletions(-) diff --git a/kernel/kthread.c b/kernel/kthread.c index 5fe7099..ab7ae57 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -150,29 +150,6 @@ struct task_struct *kthread_create(int (*threadfn)(void *data), EXPORT_SYMBOL(kthread_create); /** - * kthread_bind - bind a just-created kthread to a cpu. - * @k: thread created by kthread_create(). - * @cpu: cpu (might not be online, must be possible) for @k to run on. - * - * Description: This function is equivalent to set_cpus_allowed(), - * except that @cpu doesn't need to be online, and the thread must be - * stopped (i.e., just returned from kthread_create()). - */ -void kthread_bind(struct task_struct *k, unsigned int cpu) -{ - /* Must have done schedule() in kthread() before we set_task_cpu */ - if (!wait_task_inactive(k, TASK_UNINTERRUPTIBLE)) { - WARN_ON(1); - return; - } - set_task_cpu(k, cpu); - k->cpus_allowed = cpumask_of_cpu(cpu); - k->rt.nr_cpus_allowed = 1; - k->flags |= PF_THREAD_BOUND; -} -EXPORT_SYMBOL(kthread_bind); - -/** * kthread_stop - stop a thread created by kthread_create(). * @k: thread created by kthread_create(). * diff --git a/kernel/sched.c b/kernel/sched.c index bf21adb..5cb7d63 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1996,6 +1996,38 @@ static inline void check_class_changed(struct rq *rq, struct task_struct *p, p->sched_class->prio_changed(rq, p, oldprio, running); } +/** + * kthread_bind - bind a just-created kthread to a cpu. + * @k: thread created by kthread_create(). + * @cpu: cpu (might not be online, must be possible) for @k to run on. + * + * Description: This function is equivalent to set_cpus_allowed(), + * except that @cpu doesn't need to be online, and the thread must be + * stopped (i.e., just returned from kthread_create()). + * + * Function lives here instead of kthread.c because it messes with + * scheduler internals which require locking. + */ +void kthread_bind(struct task_struct *p, unsigned int cpu) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long flags; + + /* Must have done schedule() in kthread() before we set_task_cpu */ + if (!wait_task_inactive(p, TASK_UNINTERRUPTIBLE)) { + WARN_ON(1); + return; + } + + spin_lock_irqsave(&rq->lock, flags); + set_task_cpu(p, cpu); + p->cpus_allowed = cpumask_of_cpu(cpu); + p->rt.nr_cpus_allowed = 1; + p->flags |= PF_THREAD_BOUND; + spin_unlock_irqrestore(&rq->lock, flags); +} +EXPORT_SYMBOL(kthread_bind); + #ifdef CONFIG_SMP /* * Is this task likely cache-hot: -- 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/