From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754205Ab3AaLW7 (ORCPT ); Thu, 31 Jan 2013 06:22:59 -0500 Received: from mail-ee0-f54.google.com ([74.125.83.54]:64960 "EHLO mail-ee0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750978Ab3AaLW5 (ORCPT ); Thu, 31 Jan 2013 06:22:57 -0500 Date: Thu, 31 Jan 2013 12:22:52 +0100 From: Ingo Molnar To: Yuanhan Liu Cc: Huang Ying , Linus Torvalds , David Howells , linux-kernel@vger.kernel.org, lkp@linux.intel.com Subject: Re: aim7 performance regression by commit 5a50508 report from LKP Message-ID: <20130131112252.GB4587@gmail.com> References: <20130129082537.GS12678@yliu-dev.sh.intel.com> <20130129084400.GA5350@gmail.com> <20130129090620.GT12678@yliu-dev.sh.intel.com> <20130129091245.GB5775@gmail.com> <20130130093415.GX12678@yliu-dev.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130130093415.GX12678@yliu-dev.sh.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Yuanhan Liu wrote: > > or whether the lock hold times could be reduced drastically > > I also found one, but it doesn't sound like the one will > reduce lock hold times drastically: > > vma_lock_anon_vma() seems covered too much code at > expand_up/downwards. > > Well, again, it's quite a tiny optimization for reducing the > coverage. The fundamental problem is I think that there's a single anon vma lock for the whole workload, right? Is that really fundamentally needed, could that be spread out perhaps? ( But first we want to see how much of the regression we can fix in an equivalent-locking-patterns fashion - improving locking is a separate matter. ) Thanks, Ingo