From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752127AbaIJQgI (ORCPT ); Wed, 10 Sep 2014 12:36:08 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:43324 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750937AbaIJQgG (ORCPT ); Wed, 10 Sep 2014 12:36:06 -0400 Date: Wed, 10 Sep 2014 18:35:56 +0200 From: Peter Zijlstra To: Andi Kleen Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, eranian@google.com, tglx@linutronix.de, Andi Kleen Subject: Re: [PATCH] perf, x86: Fall back to vmalloc for BTS buffer allocation Message-ID: <20140910163556.GE4783@worktop.ger.corp.intel.com> References: <1410307401-12401-1-git-send-email-andi@firstfloor.org> <20140910075722.GL6758@twins.programming.kicks-ass.net> <20140910144012.GI4120@two.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140910144012.GI4120@two.firstfloor.org> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.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