From: Peter Zijlstra <peterz@infradead.org>
To: Andi Kleen <andi@firstfloor.org>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org,
eranian@google.com, tglx@linutronix.de,
Andi Kleen <ak@linux.intel.com>
Subject: Re: [PATCH] perf, x86: Fall back to vmalloc for BTS buffer allocation
Date: Wed, 10 Sep 2014 18:35:56 +0200 [thread overview]
Message-ID: <20140910163556.GE4783@worktop.ger.corp.intel.com> (raw)
In-Reply-To: <20140910144012.GI4120@two.firstfloor.org>
On Wed, Sep 10, 2014 at 04:40:12PM +0200, Andi Kleen wrote:
> > We did this once, and that blew up big time.
> >
> > Even now, vmalloc_fault() has a very explicit:
> >
> > WARN_ON_ONCE(in_nmi());
> >
> > So this isn't going to happen until you fix that.
>
> Good point.
>
> We just need to call vmalloc_sync_all at allocation time,
> no need to change vmalloc_fault.
Somehow that wasn't considered adequate, but lemme try and dig out that
thread. It should be somewhere...
https://lkml.org/lkml/2010/7/14/465
next prev parent reply other threads:[~2014-09-10 16:36 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 [this message]
2014-09-10 16:58 ` Peter Zijlstra
2014-09-10 18:27 ` Andi Kleen
2014-09-10 18:52 ` Peter Zijlstra
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