From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752063Ab3LRHVW (ORCPT ); Wed, 18 Dec 2013 02:21:22 -0500 Received: from lgeamrelo02.lge.com ([156.147.1.126]:49301 "EHLO LGEAMRELO02.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751072Ab3LRHVU (ORCPT ); Wed, 18 Dec 2013 02:21:20 -0500 X-AuditID: 9c93017e-b7c17ae000003961-e7-52b14cedb344 Date: Wed, 18 Dec 2013 16:21:17 +0900 From: Joonsoo Kim To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: possible regression on 3.13 when calling flush_dcache_page Message-ID: <20131218072117.GA2383@lge.com> References: <20131212143149.GI12099@ldesroches-Latitude-E6320> <20131212143618.GJ12099@ldesroches-Latitude-E6320> <20131213015909.GA8845@lge.com> <20131216144343.GD9627@ldesroches-Latitude-E6320> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131216144343.GD9627@ldesroches-Latitude-E6320> User-Agent: Mutt/1.5.21 (2010-09-15) X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 16, 2013 at 03:43:43PM +0100, Ludovic Desroches wrote: > Hello, > > On Fri, Dec 13, 2013 at 10:59:09AM +0900, Joonsoo Kim wrote: > > On Thu, Dec 12, 2013 at 03:36:19PM +0100, Ludovic Desroches wrote: > > > fix mmc mailing list address error > > > > > > On Thu, Dec 12, 2013 at 03:31:50PM +0100, Ludovic Desroches wrote: > > > > Hi, > > > > > > > > With v3.13-rc3 I have an error when the atmel-mci driver calls > > > > flush_dcache_page (log at the end of the message). > > > > > > > > Since I didn't have it before, I did a git bisect and the commit introducing > > > > the error is the following one: > > > > > > > > 106a74e slab: replace free and inuse in struct slab with newly introduced active > > > > > > > > I don't know if this commit has introduced a bug or if it has revealed a bug > > > > in the atmel-mci driver. > > > > Hello, > > > > I think that this commit may not introduce a bug. This patch remove one > > variable on slab management structure and replace variable name. So there > > is no functional change. > > > > If I have reverted this patch and other ones you did on top of it and > the issue disappear. Hello, Could you give me your '/proc/slabinfo' before/after this commit (106a74e)? And how about testing with artificially increasing size of struct slab on top of this commit (106a74e)? I really wonder why the problem happens, because this doesn't cause any functional change as far as I know. Only side-effect from this patch is decreasing size of struct slab. Thanks. diff --git a/mm/slab.c b/mm/slab.c index 2ec2336..d2240fd 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -174,6 +174,7 @@ struct slab { struct { struct list_head list; void *s_mem; /* including colour offset */ + unsigned int x; unsigned int active; /* num of objs active in slab */ }; }; > > > I doubt that side-effect of this patch reveals a bug in other place. > > Side-effect is reduced memory usage for slab management structure. It would > > makes some slabs have more objects with more density since slab management > > structure is sometimes on the page for objects. So if it diminishes, more > > objects can be in the page. > > > > Anyway, I will look at it more. If you have any progress, please let me know. > > No progress at the moment.