From: Peter Zijlstra <peterz@infradead.org>
To: Andi Kleen <ak@linux.intel.com>
Cc: Andi Kleen <andi@firstfloor.org>,
linux-kernel@vger.kernel.org, mingo@kernel.org,
eranian@google.com, tglx@linutronix.de
Subject: Re: [PATCH] perf, x86: Fall back to vmalloc for BTS buffer allocation
Date: Wed, 10 Sep 2014 20:52:38 +0200 [thread overview]
Message-ID: <20140910185238.GS6758@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140910182744.GJ5387@tassilo.jf.intel.com>
On Wed, Sep 10, 2014 at 11:27:44AM -0700, Andi Kleen wrote:
> > Note that since then we have actually fixed the 'cannot fault from NMI
> > context' thing, so we should be able to actually take those faults. I
> > suspect we can simply remove those WARNs from the vmalloc fault path,
> > but it would need double checking to see if there's no other reasons.
>
> I think we actually need to use vmalloc_sync_all, because the PEBS/DS
> microcode may do the first access, and those lose events when
> the page is not present.
You'll need to convince Linus: https://lkml.org/lkml/2010/7/14/478
prev parent reply other threads:[~2014-09-10 18:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-10 0:03 [PATCH] perf, x86: Fall back to vmalloc for BTS buffer allocation Andi Kleen
2014-09-10 7:57 ` Peter Zijlstra
2014-09-10 14:40 ` Andi Kleen
2014-09-10 16:35 ` Peter Zijlstra
2014-09-10 16:58 ` Peter Zijlstra
2014-09-10 18:27 ` Andi Kleen
2014-09-10 18:52 ` Peter Zijlstra [this message]
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