On Thu, May 26, 2011 at 08:31:28PM +0200, Sedat Dilek wrote: > On Thu, May 26, 2011 at 7:31 PM, Paul E. McKenney > <paulmck@xxxxxxxxxxxxxxxxxx> wrote: > > On Thu, May 26, 2011 at 05:48:32PM +0200, Sedat Dilek wrote: > >> On Thu, May 26, 2011 at 8:39 AM, Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx> 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] [<c102a570>] ? default_wake_function+0xb/0xd > >> [ 240.268127] [<c1021476>] ? __wake_up_common+0x33/0x5b > >> [ 240.268134] [<c129b35a>] ? _raw_spin_unlock_irqrestore+0xe/0x10 > >> [ 240.268140] [<c10234ed>] ? complete+0x34/0x3e > >> [ 240.268147] [<c1074d23>] ? cpumask_weight+0xc/0xc > >> [ 240.268157] [<c1044c97>] kthread+0x53/0x67 > >> [ 240.268162] [<c1044c44>] ? kthread_worker_fn+0x111/0x111 > >> [ 240.268169] [<c12a123e>] 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 <a.p.zijlstra@xxxxxxxxx> > > Signed-off-by: Paul E. McKenney <paul.mckenney@xxxxxxxxxx> > > Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> > > Tested-by: Yinghai Lu <yinghai@xxxxxxxxxx> > > > > 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; > > > > Thanks for the quick reply and patch! > > On 1st look at dmesg the RCU stalls are gone. > I tested against linux-next (next-20110526). > > Feel free to add: > > Tested-by: Sedat Dilek <sedat.dilek@xxxxxxxxx> Thank you for testing, Sedat! Thanx, Paul -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
