Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758110Ab1EZRbl (ORCPT ); Thu, 26 May 2011 13:31:41 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:57233 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757803Ab1EZRbj (ORCPT ); Thu, 26 May 2011 13:31:39 -0400 Date: Thu, 26 May 2011 10:31:28 -0700 From: "Paul E. McKenney" To: sedat.dilek@gmail.com Cc: Stephen Rothwell , linux-next@vger.kernel.org, LKML Subject: Re: linux-next: Tree for May 26 (RCU stalls) Message-ID: <20110526173128.GE2386@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4060 Lines: 111 On Thu, May 26, 2011 at 05:48:32PM +0200, Sedat Dilek wrote: > On Thu, May 26, 2011 at 8:39 AM, Stephen Rothwell wrote: > > Hi all, > > > > [The kernel.org mirroring is being slow today] > > > > Changes since 20110525: > > > > Linus' tree gained a build failure for which I applied a patch. > > > > The m68knommu tree lost its conflicts. > > > > The hwmon-staging lost its conflict. > > > > The wireless lost its conflict. > > > > The mmc lost its conflict. > > > > The dwmw2-iommu tree lost its conflict. > > > > The kvm tree still had its build failure so I used the version from > > next-20110524. > > > > The namespace lost its conflicts. > > > > ---------------------------------------------------------------------------- > > > > Hi, > > I see these call-traces on x86 UP machine: > > [ 240.268061] INFO: task rcun0:8 blocked for more than 120 seconds. > [ 240.268069] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" > disables this message. > [ 240.268072] rcun0 D 00000000 0 8 2 0x00000000 > [ 240.268079] f6473fb8 00000046 013131b6 00000000 c1461ac0 00000000 > 00000000 c1461ac0 > [ 240.268089] 00000000 00000000 f645dc70 f645bf60 00000003 f6473f78 > c102a570 f6473f9c > [ 240.268097] c1021476 00000000 f645bf6c 00000001 00000000 00000286 > f6473f9c c129b35a > [ 240.268106] Call Trace: > [ 240.268121] [] ? default_wake_function+0xb/0xd > [ 240.268127] [] ? __wake_up_common+0x33/0x5b > [ 240.268134] [] ? _raw_spin_unlock_irqrestore+0xe/0x10 > [ 240.268140] [] ? complete+0x34/0x3e > [ 240.268147] [] ? cpumask_weight+0xc/0xc > [ 240.268157] [] kthread+0x53/0x67 > [ 240.268162] [] ? kthread_worker_fn+0x111/0x111 > [ 240.268169] [] kernel_thread_helper+0x6/0xd > > dmesg and kernel-config are attached. Hello, Sedat, Does the following patch clear things up? Thanx, Paul ------------------------------------------------------------------------ rcu: Start RCU kthreads in TASK_INTERRUPTIBLE state Upon creation, kthreads are in TASK_UNINTERRUPTIBLE state, which can result in softlockup warnings. Because some of RCU's kthreads can legitimately be idle indefinitely, start them in TASK_INTERRUPTIBLE state in order to avoid those warnings. Suggested-by: Peter Zijlstra Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney Tested-by: Yinghai Lu diff --git a/kernel/rcutree.c b/kernel/rcutree.c index a1a8bb6..40aab8d 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1647,6 +1647,7 @@ static int __cpuinit rcu_spawn_one_cpu_kthread(int cpu) if (IS_ERR(t)) return PTR_ERR(t); kthread_bind(t, cpu); + set_task_state(t, TASK_INTERRUPTIBLE); per_cpu(rcu_cpu_kthread_cpu, cpu) = cpu; WARN_ON_ONCE(per_cpu(rcu_cpu_kthread_task, cpu) != NULL); per_cpu(rcu_cpu_kthread_task, cpu) = t; @@ -1754,6 +1755,7 @@ static int __cpuinit rcu_spawn_one_node_kthread(struct rcu_state *rsp, if (IS_ERR(t)) return PTR_ERR(t); raw_spin_lock_irqsave(&rnp->lock, flags); + set_task_state(t, TASK_INTERRUPTIBLE); rnp->node_kthread_task = t; raw_spin_unlock_irqrestore(&rnp->lock, flags); sp.sched_priority = 99; diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 049f278..a767b7d 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -1295,6 +1295,7 @@ static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp, if (IS_ERR(t)) return PTR_ERR(t); raw_spin_lock_irqsave(&rnp->lock, flags); + set_task_state(t, TASK_INTERRUPTIBLE); rnp->boost_kthread_task = t; raw_spin_unlock_irqrestore(&rnp->lock, flags); sp.sched_priority = RCU_KTHREAD_PRIO; -- 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/