Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757388AbaAIATl (ORCPT ); Wed, 8 Jan 2014 19:19:41 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:44364 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751668AbaAIATk (ORCPT ); Wed, 8 Jan 2014 19:19:40 -0500 Date: Wed, 8 Jan 2014 16:19:36 -0800 From: Andrew Morton To: Joonsoo Kim Cc: Pekka Enberg , Helge Deller , Mikulas Patocka , Andi Kleen , Christoph Lameter , LKML , linux-parisc@vger.kernel.org Subject: Re: [PATCH] fix crash when using XFS on loopback Message-Id: <20140108161936.d42bd6f7f5af528a841041d6@linux-foundation.org> In-Reply-To: <20140109001331.GA15738@lge.com> References: <20140106073549.GA25771@lge.com> <20140107014159.GA26726@lge.com> <52CDBD94.9090808@gmx.de> <20140108135930.9fc1d3a63eeb9a45dcbbb2e8@linux-foundation.org> <20140109001331.GA15738@lge.com> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 9 Jan 2014 09:13:31 +0900 Joonsoo Kim wrote: > On Wed, Jan 08, 2014 at 01:59:30PM -0800, Andrew Morton wrote: > > On Wed, 8 Jan 2014 23:37:49 +0200 Pekka Enberg wrote: > > > > > The patch looks good to me but it probably should go through Andrew's tree. > > > > yup. > > > > page_mapping() will be called quite frequently, and adding a new > > test-n-branch in there will be somewhat costly. We might end up with a > > better kernel if we were to instead revert 8456a648cf44f. How useful > > was that patch? > > Hello, > > Performance effect of this patch was decribed in the cover-letter, but > I missed to attach it to patch description. Sorry about that. > > In summary, this patch saves some memory and decreases cache-footprint > so that it increases performance. > > Here goes the description in cover-letter. > > ... > > cache-misses are reduced by this patchset, roughly 5%. > And elapsed times are also improved by 3.1% to baseline. ah, OK, thanks, useful. A few instructions added to page_mapping() won't have effects like that! -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/