From: Rusty Russell <rusty@rustcorp.com.au>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Travis <travis@sgi.com>, Ingo Molnar <mingo@redhat.com>,
Dave Jones <davej@redhat.com>,
cpufreq@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] work_on_cpu: Use our own workqueue.
Date: Thu, 29 Jan 2009 12:13:32 +1030 [thread overview]
Message-ID: <200901291213.32959.rusty@rustcorp.com.au> (raw)
In-Reply-To: <20090128114440.77abc1b2.akpm@linux-foundation.org>
On Thursday 29 January 2009 06:14:40 Andrew Morton wrote:
> It's vulnerable to the same deadlock, I think? Suppose we have:
...
> - A calls work_on_cpu() and takes woc_mutex.
>
> - Before function_which_takes_L() has started to execute, task B takes L
> then calls work_on_cpu() and task B blocks on woc_mutex.
>
> - Now function_which_takes_L() runs, and blocks on L
Agreed, but now it's a fairly simple case. Both sides have to take lock L, and both have to call work_on_cpu.
Workqueues are more generic and widespread, and an amazing amount of stuff gets called from them. That's why I felt uncomfortable with removing the one known problematic caller.
Thanks,
Rusty.
next prev parent reply other threads:[~2009-01-29 1:43 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-16 19:11 [PATCH 0/3] cpu freq: fix problems with work_on_cpu usage in acpi-cpufreq Mike Travis
2009-01-16 19:11 ` [PATCH 1/3] work_on_cpu: dont try to get_online_cpus() in work_on_cpu Mike Travis
2009-01-16 19:11 ` [PATCH 2/3] work_on_cpu: Use our own workqueue Mike Travis
2009-01-24 8:15 ` Andrew Morton
[not found] ` <200901261711.43943.rusty@rustcorp.com.au>
2009-01-26 7:01 ` Andrew Morton
2009-01-26 17:16 ` Ingo Molnar
2009-01-26 18:35 ` Andrew Morton
2009-01-26 20:20 ` Ingo Molnar
2009-01-26 20:43 ` Mike Travis
2009-01-26 21:00 ` Andrew Morton
2009-01-26 21:27 ` Ingo Molnar
2009-01-26 21:35 ` Andrew Morton
2009-01-26 21:45 ` Ingo Molnar
2009-01-26 22:01 ` Andrew Morton
2009-01-26 22:05 ` Ingo Molnar
2009-01-26 22:16 ` Andrew Morton
2009-01-26 22:20 ` Ingo Molnar
2009-01-26 22:50 ` Andrew Morton
2009-01-26 22:59 ` Ingo Molnar
2009-01-26 23:42 ` Andrew Morton
2009-01-26 23:53 ` Ingo Molnar
2009-01-27 0:42 ` Andrew Morton
2009-01-26 22:31 ` Oleg Nesterov
2009-01-26 22:15 ` Oleg Nesterov
2009-01-26 22:24 ` Ingo Molnar
2009-01-26 22:37 ` Oleg Nesterov
2009-01-26 22:42 ` Ingo Molnar
2009-01-26 21:50 ` Oleg Nesterov
2009-01-26 22:17 ` Ingo Molnar
2009-01-26 23:01 ` Mike Travis
2009-01-27 0:09 ` Oleg Nesterov
2009-01-27 7:15 ` Rusty Russell
2009-01-27 17:55 ` Oleg Nesterov
2009-01-27 7:05 ` Rusty Russell
2009-01-27 7:25 ` Andrew Morton
2009-01-27 15:28 ` Ingo Molnar
2009-01-27 16:51 ` Andrew Morton
2009-01-28 13:02 ` Rusty Russell
2009-01-28 17:19 ` Mike Travis
2009-01-28 17:32 ` Mike Travis
2009-01-29 10:39 ` Rusty Russell
2009-01-28 19:44 ` Andrew Morton
2009-01-29 1:43 ` Rusty Russell [this message]
2009-01-29 2:12 ` Andrew Morton
2009-01-30 6:03 ` Rusty Russell
2009-01-30 6:30 ` Andrew Morton
2009-01-30 13:49 ` Ingo Molnar
2009-01-30 17:08 ` Andrew Morton
2009-01-30 21:59 ` Rusty Russell
2009-01-30 22:17 ` Andrew Morton
2009-02-02 12:35 ` Rusty Russell
2009-02-03 4:06 ` Andrew Morton
2009-02-04 2:44 ` Rusty Russell
2009-02-04 3:01 ` Andrew Morton
2009-02-04 10:41 ` Rusty Russell
2009-02-04 15:36 ` Andrew Morton
2009-02-04 21:35 ` Ingo Molnar
2009-02-04 21:48 ` Andrew Morton
2009-02-04 21:54 ` Ingo Molnar
2009-02-04 23:45 ` Rusty Russell
2009-02-05 12:19 ` Pavel Machek
2009-02-05 17:44 ` Dmitry Adamushko
2009-02-10 8:54 ` Rusty Russell
2009-02-10 9:35 ` Andrew Morton
2009-02-11 0:32 ` Rusty Russell
2009-01-16 19:11 ` [PATCH 3/3] cpufreq: use work_on_cpu in acpi-cpufreq.c for drv_read and drv_write Mike Travis
2009-01-16 23:38 ` [PATCH 0/3] cpu freq: fix problems with work_on_cpu usage in acpi-cpufreq [PULL request] Mike Travis
2009-01-17 22:08 ` Ingo Molnar
2009-01-19 17:11 ` Mike Travis
2009-01-19 17:26 ` Ingo Molnar
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