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Date: Thu, 10 Jan 2008 14:45:43 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Thomas Gleixner <tglx@linutronix.de>,
       "Brown, Len" <len.brown@intel.com>,
       Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>,
       Adam Belay <abelay@novell.com>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
       Andi Kleen <ak@suse.de>
Subject: Re: [PATCH] Kick CPUS that might be sleeping in cpus_idle_wait
Message-ID: <20080110134539.GD5886@elte.hu>
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* Steven Rostedt <rostedt@goodmis.org> wrote:

> On Wed, 2008-01-09 at 15:42 -0500, Steven Rostedt wrote:
> > This patch is different than the first patch I sent out.
> > This one just sends an IPI to all CPUS that don't check in after 1 sec.
> > 
> > 
> > Sometimes cpu_idle_wait gets stuck because it might miss CPUS that are
> > already in idle, have no tasks waiting to run and have no interrupts
> > going to them.  This is common on bootup when switching cpu idle
> > governors.
> > 
> > This patch gives those CPUS that don't check in an IPI kick.
> 
> FYI, I just hit this hang on 2.6.24-rc6 without any extra patches. So, 
> unless 2.6.24-rc7 did anything to fix this issue, this is a high 
> priority bug (IMHO).

i'm wondering why this only triggered now. Is this something new in 
2.6.24?

	Ingo