From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Tejun Heo <tj@kernel.org>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>,
"x86@kernel.org" <x86@kernel.org>,
"mingo@elte.hu" <mingo@elte.hu>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] stop_machine: kill __stop_machine()
Date: Thu, 16 Jun 2011 20:36:02 +0200 [thread overview]
Message-ID: <1308249362.13240.275.camel@twins> (raw)
In-Reply-To: <20110616182805.GD2611@htj.dyndns.org>
On Thu, 2011-06-16 at 20:28 +0200, Tejun Heo wrote:
> Peter, I don't think it's that simple. get_online_cpus() itself can't
> create circular dependency by itself. It allows recursing. The chain
> involves cpu_hotplug_begin() which returns with hotplug mutex held.
Right, its like:
mutex_lock(&a);
get_online_cpus();
vs
cpu_hotplug_begin()
mutex_lock(&a);
that will really deadlock
next prev parent reply other threads:[~2011-06-16 18:36 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-14 17:06 [PATCHSET] stop_machine: implement stop_machine_from_offline_cpu() Tejun Heo
2011-06-14 17:06 ` [PATCH 1/3] stop_machine: kill __stop_machine() Tejun Heo
2011-06-16 12:12 ` Peter Zijlstra
2011-06-16 12:44 ` Tejun Heo
2011-06-16 17:37 ` Suresh Siddha
2011-06-16 17:55 ` Peter Zijlstra
2011-06-16 18:17 ` Suresh Siddha
2011-06-16 18:28 ` Tejun Heo
2011-06-16 18:36 ` Peter Zijlstra [this message]
2011-06-16 18:44 ` Suresh Siddha
2011-06-16 18:28 ` Peter Zijlstra
2011-06-14 17:06 ` [PATCH 2/3] stop_machine: reorganize stop_cpus() implementation Tejun Heo
2011-06-14 17:06 ` [PATCH 3/3] stop_machine: implement stop_machine_from_offline_cpu() Tejun Heo
2011-06-16 12:10 ` [PATCHSET] " Peter Zijlstra
2011-06-16 12:15 ` Tejun Heo
2011-06-16 17:21 ` Suresh Siddha
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