From: Tejun Heo <tj@kernel.org>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: Ben Greear <greearb@candelatech.com>, linux-wireless@vger.kernel.org
Subject: Re: [PATCH] mac80211: Fix deadlock in ieee80211_do_stop.
Date: Wed, 17 Nov 2010 09:47:37 +0100 [thread overview]
Message-ID: <4CE396A9.1050908@kernel.org> (raw)
In-Reply-To: <1289929258.3673.1.camel@jlt3.sipsolutions.net>
Hey, Johannes.
On 11/16/2010 06:40 PM, Johannes Berg wrote:
> On Tue, 2010-11-16 at 15:19 +0100, Tejun Heo wrote:
>
>> 3. What if you replace it with the following?
>>
>> alloc_workqueue(wiphy_name(local->hw.wiphy), WQ_NON_REENTRANT, 0)
>
> Wait ... what's the difference between this and
> alloc_ordered_workqueue() then?
alloc_ordered_workqueue() is fully ordered. ie. Works are executed in
the queued order regardless of where it's queued, which also implies
that there is only one work in progress at any given time.
WQ_NON_REENTRANT doesn't guarantee ordered execution but it guarantees
that a single work is not executed concurrently on multiple CPUs. I'm
not sure whether this would be safe for the workqueue used by mac80211
but it should let us know whether the workqueue is choked due to a
work which is executing for long time. In the long run, if using non
reentrant is safe for mac80211, using it would be much better.
Thanks.
--
tejun
next prev parent reply other threads:[~2010-11-17 8:47 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-12 20:07 [PATCH] mac80211: Fix deadlock in ieee80211_do_stop greearb
2010-11-12 20:08 ` Luis R. Rodriguez
2010-11-12 20:16 ` Ben Greear
2010-11-12 20:49 ` Johannes Berg
2010-11-12 20:57 ` Ben Greear
2010-11-12 21:08 ` Johannes Berg
2010-11-12 21:51 ` Ben Greear
2010-11-13 10:34 ` Tejun Heo
2010-11-15 21:16 ` Ben Greear
2010-11-16 14:19 ` Tejun Heo
2010-11-16 16:51 ` Ben Greear
2010-11-17 8:55 ` Tejun Heo
2010-11-17 17:37 ` Ben Greear
2010-11-16 17:40 ` Johannes Berg
2010-11-17 8:47 ` Tejun Heo [this message]
2010-11-17 18:53 ` Johannes Berg
2010-11-17 18:59 ` Ben Greear
2010-11-17 19:03 ` Johannes Berg
2010-11-18 6:34 ` Tejun Heo
2010-11-18 7:07 ` Johannes Berg
2010-11-18 7:22 ` Tejun Heo
2010-11-18 16:59 ` Johannes Berg
2010-11-19 14:34 ` Tejun Heo
2010-11-19 17:57 ` Johannes Berg
2010-11-19 20:55 ` Ben Greear
2010-11-19 22:27 ` Luis R. Rodriguez
2010-12-08 17:36 ` Ben Greear
2010-12-08 18:19 ` Ben Greear
2010-12-08 18:28 ` Ben Greear
2010-12-09 14:34 ` Tejun Heo
2010-12-09 14:42 ` Johannes Berg
2010-12-09 14:46 ` Tejun Heo
2010-12-09 16:17 ` Tejun Heo
[not found] ` <4D0156F6.4000306@candelate ch.com>
2010-12-09 17:27 ` Ben Greear
2010-12-09 22:23 ` Ben Greear
2010-12-10 15:11 ` Tejun Heo
2010-12-10 16:35 ` Ben Greear
2010-11-18 17:55 ` Ben Greear
2010-11-18 18:04 ` Tejun Heo
2010-11-18 18:11 ` Ben Greear
2010-11-17 20:13 ` Ben Greear
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