From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752777AbaIJS1z (ORCPT ); Wed, 10 Sep 2014 14:27:55 -0400 Received: from mga09.intel.com ([134.134.136.24]:1929 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751044AbaIJS1x (ORCPT ); Wed, 10 Sep 2014 14:27:53 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,500,1406617200"; d="scan'208";a="571294453" Date: Wed, 10 Sep 2014 11:27:44 -0700 From: Andi Kleen To: Peter Zijlstra Cc: Andi Kleen , 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 Message-ID: <20140910182744.GJ5387@tassilo.jf.intel.com> References: <1410307401-12401-1-git-send-email-andi@firstfloor.org> <20140910075722.GL6758@twins.programming.kicks-ass.net> <20140910144012.GI4120@two.firstfloor.org> <20140910163556.GE4783@worktop.ger.corp.intel.com> <20140910165848.GA11901@worktop.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140910165848.GA11901@worktop.ger.corp.intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > 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. -Andi -- ak@linux.intel.com -- Speaking for myself only