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From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>, Gautham R Shenoy <ego@in.ibm.com>,
	Johannes Berg <johannes@sipsolutions.net>,
	LKML <linux-kernel@vger.kernel.org>,
	Oleg Nesterov <oleg@tv-sign.ru>
Subject: Re: Problem with freezable workqueues
Date: Wed, 28 Feb 2007 08:31:13 +0530	[thread overview]
Message-ID: <20070228030113.GJ29179@in.ibm.com> (raw)
In-Reply-To: <200702272251.28844.rjw@sisk.pl>

On Tue, Feb 27, 2007 at 10:51:27PM +0100, Rafael J. Wysocki wrote:
> We have a problem with freezable workqueues in 2.6.21-rc1 and in -mm
> (there are only two of them, in XFS, but still).  Namely, their worker threads
> deadlock with workqueue_cpu_callback() that gets called during the CPU hotplug,
> becuase workqueue_cpu_callback() tries to stop these threads while they are
> frozen (disable_nonboot_cpus() happens after we've frozen tasks).

This problem (of kthread_stopping a frozen thread) was there when we
implemented freezer-based cpu hotplug. We worked around that in the
callbacks by thawing the worker thread first before kthread_stopping it,
which is working pretty neatly.

Should that fix the issue? 

-- 
Regards,
vatsa

  parent reply	other threads:[~2007-02-28  3:01 UTC|newest]

Thread overview: 45+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-27 21:51 Problem with freezable workqueues Rafael J. Wysocki
2007-02-27 23:28 ` Oleg Nesterov
2007-02-27 23:36   ` Johannes Berg
2007-02-28  0:00     ` Rafael J. Wysocki
2007-02-28  0:00       ` Johannes Berg
2007-02-28 18:06     ` Gautham R Shenoy
2007-02-27 23:57   ` Rafael J. Wysocki
2007-02-28  0:01     ` Johannes Berg
2007-02-28  0:08       ` Rafael J. Wysocki
2007-02-28  1:14         ` Nigel Cunningham
2007-02-28 10:59           ` Rafael J. Wysocki
2007-02-28 20:36           ` Johannes Berg
2007-02-28  3:07     ` Srivatsa Vaddagiri
2007-02-28  8:48       ` Oleg Nesterov
2007-02-28  9:10         ` Srivatsa Vaddagiri
2007-02-28  9:43           ` Oleg Nesterov
2007-02-28 11:09           ` Rafael J. Wysocki
2007-02-28 18:17       ` Gautham R Shenoy
2007-02-28 18:41         ` Rafael J. Wysocki
2007-02-28  8:54     ` Pavel Machek
2007-02-28  3:01 ` Srivatsa Vaddagiri [this message]
2007-02-28  3:51   ` Srivatsa Vaddagiri
2007-02-28 11:11     ` Rafael J. Wysocki
2007-02-28 13:17       ` Srivatsa Vaddagiri
2007-02-28 13:27         ` Srivatsa Vaddagiri
2007-02-28 17:41           ` Rafael J. Wysocki
2007-02-28 17:40         ` Rafael J. Wysocki
2007-02-28 19:17         ` Rafael J. Wysocki
2007-02-28 19:32           ` Oleg Nesterov
2007-02-28 19:43             ` Rafael J. Wysocki
2007-02-28 20:08               ` Oleg Nesterov
2007-02-28 20:25                 ` Rafael J. Wysocki
2007-02-28 20:35                   ` Oleg Nesterov
2007-02-28 22:39                     ` Rafael J. Wysocki
2007-02-28 22:44                       ` Pavel Machek
2007-02-28 23:54                         ` [PATCH] Make XFS workqueues nonfreezable Rafael J. Wysocki
2007-03-01  8:03                           ` Andrew Morton
2007-03-01  9:15                             ` Pavel Machek
2007-03-01  9:25                               ` Andrew Morton
2007-02-28 21:16                   ` Problem with freezable workqueues Pavel Machek
2007-03-06  0:30 ` Johannes Berg
2007-03-06 20:31   ` Rafael J. Wysocki
2007-03-06 22:25     ` Nigel Cunningham
2007-03-06 22:57       ` Rafael J. Wysocki
2007-03-07 23:10     ` Johannes Berg

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