From: Oleg Nesterov <oleg@redhat.com>
To: Amerigo Wang <amwang@redhat.com>
Cc: linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
Rusty Russell <rusty@rustcorp.com.au>,
akpm@linux-foundation.org, Ingo Molnar <mingo@elte.hu>
Subject: Re: [Patch] workqueue: move lockdep annotations up to destroy_workqueue()
Date: Wed, 31 Mar 2010 13:25:59 +0200 [thread overview]
Message-ID: <20100331112559.GA17747@redhat.com> (raw)
In-Reply-To: <20100331105534.5601.50813.sendpatchset@localhost.localdomain>
On 03/31, Amerigo Wang wrote:
>
> This fixes a lockdep warning when invoking destroy_workqueue(),
> because the lockdep annotations are invoked under cpu_add_remove_lock.
Confused. Why does lockdep complains?
> So, move the lockdep annotations before taking cpu_add_remove_lock
> in destroy_workqueue(), this will not affect the original purpose
> of adding them for destroy_workqueue() etc.
>
> However, it will affect another caller of cleanup_workqueue_thread(),
> that is, workqueue_cpu_callback(). This should be fine, because there
> are no other cases than cpu hotplug could call it.
OK, but nobody should take cpu_maps_update_begin() under wq->lockdep_map,
in particular work->func() must not.
I must have missed something, but it seems to me this patch tries to
supress the valid warning.
Could you please clarify?
Oleg.
next prev parent reply other threads:[~2010-03-31 11:28 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-31 10:51 [Patch] workqueue: move lockdep annotations up to destroy_workqueue() Amerigo Wang
2010-03-31 11:25 ` Oleg Nesterov [this message]
2010-04-01 2:45 ` Cong Wang
2010-04-01 3:56 ` Tejun Heo
2010-04-01 4:09 ` Cong Wang
2010-04-01 4:14 ` Tejun Heo
2010-04-01 4:28 ` Cong Wang
2010-04-01 4:59 ` Tejun Heo
2010-04-01 5:20 ` Cong Wang
2010-04-01 6:05 ` Cong Wang
2010-04-01 6:07 ` Cong Wang
2010-04-01 6:28 ` Tejun Heo
2010-04-01 16:36 ` Oleg Nesterov
2010-04-02 5:00 ` Cong Wang
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