From: Ingo Molnar <mingo@elte.hu>
To: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Johannes Berg <johannes@sipsolutions.net>,
Ingo Molnar <mingo@redhat.com>,
Arjan van de Ven <arjan@linux.intel.com>,
Linux Kernel list <linux-kernel@vger.kernel.org>,
linux-wireless <linux-wireless@vger.kernel.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Sattler <tsattler@gmx.de>
Subject: Re: [RFC/PATCH] debug workqueue deadlocks with lockdep
Date: Tue, 3 Jul 2007 21:42:29 +0200 [thread overview]
Message-ID: <20070703194229.GB493@elte.hu> (raw)
In-Reply-To: <20070703173112.GA108@tv-sign.ru>
* Oleg Nesterov <oleg@tv-sign.ru> wrote:
> Now we have a false positive if some time we queue B into that
> workqueue, and this is not good.
>
> We can avoid this problem if we put lockdep_map into work_struct, so
> that wait_on_work() "locks" work->lockdep_map, while flush_workqueue()
> takes wq->lockdep_map.
>
> But probably we don't need this right now, at least until we really
> have a lot of false positives while converting from flush_workqueue()
> to cancel_work_sync/cancel_delayed_work_sync.
would be nice to map the real dependencies. Adding another lockdep_map
is really low-cost and the lack of false positives is reassuring.
Ingo
next prev parent reply other threads:[~2007-07-03 19:42 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-27 18:40 [RFC/PATCH] debug workqueue deadlocks with lockdep Johannes Berg
2007-06-28 16:33 ` Johannes Berg
2007-06-28 17:33 ` Johannes Berg
2007-06-30 8:05 ` Ingo Molnar
2007-06-30 11:46 ` Oleg Nesterov
2007-07-02 8:37 ` Johannes Berg
2007-07-02 13:03 ` Johannes Berg
2007-07-03 17:31 ` Oleg Nesterov
2007-07-03 19:42 ` Ingo Molnar [this message]
2007-07-04 11:49 ` Johannes Berg
2007-07-04 12:21 ` Ingo Molnar
2007-07-04 13:59 ` Johannes Berg
2007-07-04 12:25 ` Ingo Molnar
2007-07-04 12:52 ` Oleg Nesterov
2007-07-04 13:57 ` Johannes Berg
2007-07-05 8:43 ` Ingo Molnar
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