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From: Frederic Weisbecker <fweisbec@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Christoph Lameter <cl@linux.com>,
	Kevin Hilman <khilman@linaro.org>,
	Lai Jiangshan <laijs@cn.fujitsu.com>,
	Mike Galbraith <bitbucket@online.de>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Viresh Kumar <viresh.kumar@linaro.org>
Subject: Re: [PATCH 2/4] workqueue: Split apply attrs code from its locking
Date: Thu, 1 May 2014 16:40:21 +0200	[thread overview]
Message-ID: <20140501144018.GA25369@localhost.localdomain> (raw)
In-Reply-To: <20140424144832.GD14460@htj.dyndns.org>

On Thu, Apr 24, 2014 at 10:48:32AM -0400, Tejun Heo wrote:
> On Thu, Apr 24, 2014 at 04:37:34PM +0200, Frederic Weisbecker wrote:
> > +static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
> > +					const struct workqueue_attrs *attrs)
> >  {
> >  	struct workqueue_attrs *new_attrs, *tmp_attrs;
> >  	struct pool_workqueue **pwq_tbl, *dfl_pwq;
> > @@ -3976,15 +3960,6 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
> >  	copy_workqueue_attrs(tmp_attrs, new_attrs);
> >  
> >  	/*
> > -	 * CPUs should stay stable across pwq creations and installations.
> > -	 * Pin CPUs, determine the target cpumask for each node and create
> > -	 * pwqs accordingly.
> > -	 */
> > -	get_online_cpus();
> > -
> > -	mutex_lock(&wq_pool_mutex);
> 
> lockdep_assert_held()

Not sure... Only a small part of the function actually needs to be locked. Namely
those doing the pwq allocations, which already have the lockdep_assert_held().

  reply	other threads:[~2014-05-01 14:40 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-24 14:37 [RFC PATCH 0/4] workqueue: Introduce low-level unbound wq sysfs cpumask Frederic Weisbecker
2014-04-24 14:37 ` [PATCH 1/4] workqueue: Create low-level unbound workqueues cpumask Frederic Weisbecker
2014-04-24 15:37   ` Tejun Heo
2014-05-01 15:01     ` Frederic Weisbecker
2014-05-01 15:02       ` Tejun Heo
2014-05-01 15:09         ` Frederic Weisbecker
2014-05-01 15:13           ` Tejun Heo
2014-04-24 22:42   ` Kevin Hilman
2014-04-24 14:37 ` [PATCH 2/4] workqueue: Split apply attrs code from its locking Frederic Weisbecker
2014-04-24 14:48   ` Tejun Heo
2014-05-01 14:40     ` Frederic Weisbecker [this message]
2014-05-01 14:41       ` Tejun Heo
2014-04-24 14:37 ` [PATCH 3/4] workqueue: Allow modifying low level unbound workqueue cpumask Frederic Weisbecker
2014-04-24 15:30   ` Tejun Heo
2014-05-01 14:49     ` Frederic Weisbecker
2014-04-24 14:37 ` [PATCH 4/4] workqueue: Handle ordered workqueues on cpumask_unbounds change Frederic Weisbecker
2014-04-24 15:33   ` Tejun Heo
2014-05-01 14:51     ` Frederic Weisbecker

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