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From: Michael Ellerman <mpe@ellerman.id.au>
To: Tejun Heo <htejun@gmail.com>, Peter Zijlstra <peterz@infradead.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Abdul Haleem <abdhalee@linux.vnet.ibm.com>,
	Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] workqueue:Fix affinity of an unbound worker of a node with 1 online CPU
Date: Fri, 17 Jun 2016 11:49:36 +1000	[thread overview]
Message-ID: <1466128176.12899.7.camel@ellerman.id.au> (raw)
In-Reply-To: <20160616193905.GC3262@mtj.duckdns.org>

On Thu, 2016-06-16 at 15:39 -0400, Tejun Heo wrote:
> On Thu, Jun 16, 2016 at 02:45:48PM +0200, Peter Zijlstra wrote:
> > Subject: workqueue: Fix setting affinity of unbound worker threads
> > From: Peter Zijlstra <peterz@infradead.org>
> > Date: Thu Jun 16 14:38:42 CEST 2016
> > 
> > With commit e9d867a67fd03ccc ("sched: Allow per-cpu kernel threads to
> > run on online && !active"), __set_cpus_allowed_ptr() expects that only
> > strict per-cpu kernel threads can have affinity to an online CPU which
> > is not yet active.
> > 
> > This assumption is currently broken in the CPU_ONLINE notification
> > handler for the workqueues where restore_unbound_workers_cpumask()
> > calls set_cpus_allowed_ptr() when the first cpu in the unbound
> > worker's pool->attr->cpumask comes online. Since
> > set_cpus_allowed_ptr() is called with pool->attr->cpumask in which
> > only one CPU is online which is not yet active, we get the following
> > WARN_ON during an CPU online operation.
> 
> Applied to wq/for-4.7-fixes.

Thanks all.

cheers

  reply	other threads:[~2016-06-17  1:49 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <573D9C2D.4020609@linux.vnet.ibm.com>
     [not found] ` <20160526151137.GA26508@in.ibm.com>
2016-06-07 12:29   ` WARNING at kernel/sched/core.c:1166 while booting 4.6.0 mainline on ppc64le bare metal Abdul Haleem
2016-06-07 15:14     ` [PATCH 0/2] Fix CPU Online handling for unbounded worker threads Gautham R. Shenoy
2016-06-07 15:14       ` [PATCH 1/2] workqueue: Move wq_update_unbound_numa() to the beginning of CPU_ONLINE Gautham R. Shenoy
2016-06-15 15:53         ` Tejun Heo
2016-06-15 19:28           ` Gautham R Shenoy
2016-06-16 19:35             ` Tejun Heo
2016-06-21 14:12               ` Gautham R Shenoy
2016-06-21 15:36                 ` Tejun Heo
2016-06-21 19:37                   ` Peter Zijlstra
2016-06-21 19:43                     ` Tejun Heo
2016-06-21 19:47                       ` Peter Zijlstra
2016-06-22  5:15                         ` Gautham R Shenoy
2016-06-24  9:00               ` [tip:sched/urgent] sched/core: Allow kthreads to fall back to online && !active cpus tip-bot for Tejun Heo
2016-06-07 15:14       ` [PATCH 2/2] workqueue:Fix affinity of an unbound worker of a node with 1 online CPU Gautham R. Shenoy
2016-06-08  6:03         ` Abdul Haleem
2016-06-14 11:22         ` Peter Zijlstra
2016-06-15 10:19           ` Gautham R Shenoy
2016-06-15 11:32             ` Peter Zijlstra
2016-06-15 12:50               ` Gautham R Shenoy
2016-06-15 13:14                 ` Peter Zijlstra
2016-06-15 16:01                   ` Tejun Heo
2016-06-16 12:11                     ` Michael Ellerman
2016-06-16 12:45                       ` Peter Zijlstra
2016-06-16 19:39                         ` Tejun Heo
2016-06-17  1:49                           ` Michael Ellerman [this message]
2016-07-15  5:27                           ` Gautham R Shenoy
     [not found]                           ` <57887507.911f240a.687de.08c5SMTPIN_ADDED_BROKEN@mx.google.com>
2016-07-15 12:10                             ` Tejun Heo
2016-06-13  5:44       ` [PATCH 0/2] Fix CPU Online handling for unbounded worker threads Gautham R Shenoy

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