From: Borislav Petkov <bp@alien8.de>
To: Michael Wang <wangyun@linux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@linaro.org>, Tejun Heo <tj@kernel.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Jiri Kosina <jkosina@suse.cz>,
Frederic Weisbecker <fweisbec@gmail.com>,
Tony Luck <tony.luck@intel.com>,
linux-kernel@vger.kernel.org, x86@kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
rjw@sisk.pl, cpufreq@vger.kernel.org, linux-pm@vger.kernel.org
Subject: Re: NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule, round 2
Date: Tue, 21 May 2013 09:21:40 +0200 [thread overview]
Message-ID: <20130521072140.GA4866@pd.tnic> (raw)
In-Reply-To: <519ADA03.5060206@linux.vnet.ibm.com>
On Tue, May 21, 2013 at 10:20:51AM +0800, Michael Wang wrote:
> This is not enough to prove that policy->cpus is wrong, the cpu could
> be online when get from policy->cpus, but offline when checked here,
> since hotplug is able to happen during the period.
Strictly speaking you're correct but I don't do any hotplug besides the
one-time thing which is part of halting the box.
> I don't get it...
>
> get_online_cpus() is just stop hotplug happen after it was invoked, so
> unless policy->cpus is really wrong, otherwise all the cpu it masked
> won't go offline any more.
Yes, that's my impression too - at the point we do gov_queue_work,
policy->cpus already contains offline cpus.
> This protect nothing...before we go here, the cpu could already
> offline, nothing changed...
Yes, but I don't want to schedule work on an offlined cpu and that is
ensured here.
> If you really want to confirm the policy->cpus was wrong, the way
> should be apply the fix I suggested, than check online in here.
Sure, feel free to get a box, enable NO_HZ_FULL and do all the
experimentations you desire. I surely cannot be the only one who
triggers this.
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2013-05-21 7:21 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-09 12:29 NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule Jiri Kosina
2013-05-09 12:50 ` Borislav Petkov
2013-05-09 12:58 ` Borislav Petkov
2013-05-15 18:45 ` Paul E. McKenney
2013-05-15 22:43 ` Borislav Petkov
2013-05-15 23:55 ` Paul E. McKenney
2013-05-17 13:56 ` NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule, round 2 Borislav Petkov
2013-05-20 3:16 ` Michael Wang
2013-05-20 4:50 ` Borislav Petkov
2013-05-20 6:23 ` Michael Wang
2013-05-20 6:47 ` Borislav Petkov
2013-05-20 6:58 ` Michael Wang
2013-05-20 7:06 ` Michael Wang
2013-05-20 7:12 ` Viresh Kumar
2013-05-20 7:25 ` Michael Wang
2013-05-20 8:56 ` Michael Wang
2013-05-20 9:09 ` Viresh Kumar
2013-05-20 9:24 ` Michael Wang
2013-05-20 13:23 ` Borislav Petkov
2013-05-20 13:43 ` Viresh Kumar
2013-05-20 15:08 ` Borislav Petkov
2013-05-21 2:20 ` Michael Wang
2013-05-21 2:37 ` Michael Wang
2013-05-21 7:21 ` Borislav Petkov [this message]
2013-05-21 7:58 ` Michael Wang
2013-05-20 7:36 ` Tejun Heo
2013-05-20 8:10 ` Frederic Weisbecker
2013-05-20 9:31 ` Srivatsa S. Bhat
2013-05-20 9:40 ` Viresh Kumar
2013-05-20 10:24 ` Viresh Kumar
2013-06-04 21:20 ` Jiri Kosina
2013-06-05 2:30 ` Michael Wang
2013-06-05 8:08 ` Jiri Kosina
2013-06-05 8:12 ` Michael Wang
2013-05-10 0:29 ` NOHZ: WARNING: at arch/x86/kernel/smp.c:123 native_smp_send_reschedule Frederic Weisbecker
2013-05-10 9:28 ` Borislav Petkov
2013-05-10 9:26 ` Frederic Weisbecker
2013-05-10 9:37 ` Ingo Molnar
2013-05-10 9:45 ` Borislav Petkov
2013-05-10 15:31 ` Frederic Weisbecker
2013-05-10 9:43 ` Borislav Petkov
2013-05-10 15:42 ` Jiri Kosina
2013-05-10 15:03 ` Jiri Kosina
2013-05-10 15:21 ` Borislav Petkov
2013-05-10 15:43 ` Frederic Weisbecker
2013-05-10 16:23 ` Borislav Petkov
2013-05-10 21:38 ` Frederic Weisbecker
2013-05-13 14:56 ` Jiri Kosina
2013-05-13 19:40 ` Thomas Gleixner
2013-05-13 20:01 ` Jiri Kosina
2013-05-14 15:46 ` [tip:timers/urgent] tick: Don't invoke tick_nohz_stop_sched_tick( ) if the cpu is offline tip-bot for Thomas Gleixner
2013-05-15 19:41 ` Frederic Weisbecker
2013-05-16 14:06 ` Thomas Gleixner
2013-05-16 14:15 ` Borislav Petkov
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