From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755526Ab2GQPex (ORCPT ); Tue, 17 Jul 2012 11:34:53 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:14865 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752078Ab2GQPcp (ORCPT ); Tue, 17 Jul 2012 11:32:45 -0400 X-Authority-Analysis: v=2.0 cv=ZuBv2qHG c=1 sm=0 a=s5Htg7xnQOKvHEu9STBOug==:17 a=OpT9cpI26MMA:10 a=Ciwy3NGCPMMA:10 a=ORad0jiYtisA:10 a=5SG0PmZfjMsA:10 a=bbbx4UPp9XUA:10 a=meVymXHHAAAA:8 a=20KFwNOVAAAA:8 a=oaIC6Tjh_shP-Nb8facA:9 a=jEp0ucaQiEUA:10 a=jeBq3FmKZ4MA:10 a=Zh68SRI7RUMA:10 a=s5Htg7xnQOKvHEu9STBOug==:117 X-Cloudmark-Score: 0 X-Originating-IP: 72.230.195.127 Message-Id: <20120717153244.715177134@goodmis.org> User-Agent: quilt/0.60-1 Date: Tue, 17 Jul 2012 11:31:25 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , John Kacur Subject: [PATCH RT 10/12] workqueue: Revert workqueue: Fix PF_THREAD_BOUND abuse References: <20120717153115.606116459@goodmis.org> Content-Disposition: inline; filename=0010-workqueue-Revert-workqueue-Fix-PF_THREAD_BOUND-abuse.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steven Rostedt Revert commit Author: Peter Zijlstra Date: Mon Oct 3 12:43:25 2011 +0200 workqueue: Fix PF_THREAD_BOUND abuse As TREAD_BOUND no longer affects cpu down, and this code introduced a lot of races with taking down a CPU. Signed-off-by: Steven Rostedt Signed-off-by: Thomas Gleixner --- kernel/workqueue.c | 29 +++++++++-------------------- 1 file changed, 9 insertions(+), 20 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index bc867e8..1e7f9c7 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -1283,14 +1283,8 @@ __acquires(&gcwq->lock) return false; if (task_cpu(task) == gcwq->cpu && cpumask_equal(¤t->cpus_allowed, - get_cpu_mask(gcwq->cpu))) { - /* - * Since we're binding to a particular cpu and need to - * stay there for correctness, mark us PF_THREAD_BOUND. - */ - task->flags |= PF_THREAD_BOUND; + get_cpu_mask(gcwq->cpu))) return true; - } spin_unlock_irq(&gcwq->lock); /* @@ -1304,18 +1298,6 @@ __acquires(&gcwq->lock) } } -static void worker_unbind_and_unlock(struct worker *worker) -{ - struct global_cwq *gcwq = worker->gcwq; - struct task_struct *task = worker->task; - - /* - * Its no longer required we're PF_THREAD_BOUND, the work is done. - */ - task->flags &= ~PF_THREAD_BOUND; - spin_unlock_irq(&gcwq->lock); -} - static struct worker *alloc_worker(void) { struct worker *worker; @@ -1378,9 +1360,15 @@ static struct worker *create_worker(struct global_cwq *gcwq, bool bind) if (IS_ERR(worker->task)) goto fail; + /* + * A rogue worker will become a regular one if CPU comes + * online later on. Make sure every worker has + * PF_THREAD_BOUND set. + */ if (bind && !on_unbound_cpu) kthread_bind(worker->task, gcwq->cpu); else { + worker->task->flags |= PF_THREAD_BOUND; if (on_unbound_cpu) worker->flags |= WORKER_UNBOUND; } @@ -2057,7 +2045,7 @@ repeat: if (keep_working(gcwq)) wake_up_worker(gcwq); - worker_unbind_and_unlock(rescuer); + spin_unlock_irq(&gcwq->lock); } schedule(); @@ -3007,6 +2995,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt, if (IS_ERR(rescuer->task)) goto err; + rescuer->task->flags |= PF_THREAD_BOUND; wake_up_process(rescuer->task); } -- 1.7.10.4