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Subject: Re: [PATCH v2] oprofile, x86: Move memory allocation for ppro out
 of per cpu
From: Peter Zijlstra <peterz@infradead.org>
To: Robert Richter <robert.richter@amd.com>
Cc: Maarten Lankhorst <m.b.lankhorst@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        "x86@kernel.org" <x86@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Andi Kleen <andi@firstfloor.org>
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Date: Mon, 01 Aug 2011 14:37:11 +0200
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On Mon, 2011-08-01 at 09:07 +0200, Robert Richter wrote:
> Can you please describe the root problem more precisely. Why can't you
> run it on -rt? What is broken? 

Because the allocators don't work from atomic context anymore. Now -rt
doesn't have a lot of real atomic contexts left so its usually not much
of a problem, but CPU_STARTING and actual IPIs are of course still
atomic.