From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Gautham Shenoy <ego@in.ibm.com>, Ingo Molnar <mingo@elte.hu>,
Jiri Slaby <jirislaby@gmail.com>, Li Zefan <lizf@cn.fujitsu.com>,
Miao Xie <miaox@cn.fujitsu.com>, Paul Menage <menage@google.com>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
Rusty Russell <rusty@rustcorp.com.au>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/3] resend, cpuset/hotplug fixes
Date: Fri, 11 Sep 2009 15:53:24 +0800 [thread overview]
Message-ID: <4AAA01F4.3050502@cn.fujitsu.com> (raw)
In-Reply-To: <1252654410.7126.1.camel@laptop>
Peter Zijlstra wrote:
> On Fri, 2009-09-11 at 15:15 +0800, Lai Jiangshan wrote:
>> One other minor thing:
>> Oleg's patch may introduce a trouble in PREEEMPT_RT tree, because
>> spinlock in RT is also mutex. Likely I'm wrong.
>
> But they have priority-inheritance, hence you cannot create a deadlock
> through preemption. If the kstopmachine thread blocks on a mutex, the
> owner gets boosted to kstopmachine's prio and runs to completion, after
> that kstopmachine continues.
>
The deadlock is because the owner is at the dead cpu, It's not because
the owner's prio is low. priority-inheritance can't help it.
I think we need to use a raw spinlock.
next prev parent reply other threads:[~2009-09-11 7:54 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-10 19:21 [PATCH 0/3] resend, cpuset/hotplug fixes Oleg Nesterov
2009-09-10 20:18 ` Rafael J. Wysocki
2009-09-10 20:53 ` Peter Zijlstra
2009-09-11 7:15 ` Lai Jiangshan
2009-09-11 7:33 ` Peter Zijlstra
2009-09-11 7:53 ` Lai Jiangshan [this message]
2009-09-11 7:57 ` Peter Zijlstra
2009-09-11 7:37 ` Peter Zijlstra
2009-09-11 18:03 ` Oleg Nesterov
-- strict thread matches above, loose matches on Subject: below --
2009-09-10 19:13 Oleg Nesterov
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