Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758490AbbGQPZJ (ORCPT ); Fri, 17 Jul 2015 11:25:09 -0400 Received: from forward-corp1m.cmail.yandex.net ([5.255.216.100]:43903 "EHLO forward-corp1m.cmail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756824AbbGQPZH (ORCPT ); Fri, 17 Jul 2015 11:25:07 -0400 Authentication-Results: smtpcorp4.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Message-ID: <55A91E4D.2080203@yandex-team.ru> Date: Fri, 17 Jul 2015 18:25:01 +0300 From: Konstantin Khlebnikov User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Christoph Lameter , Konstantin Khlebnikov CC: "linux-mm@kvack.org" , Andrew Morton , Linux Kernel Mailing List Subject: Re: [PATCH 2/2] mm/slub: disable merging after enabling debug in runtime References: <20150714131704.21442.17939.stgit@buzz> <20150714131705.21442.99279.stgit@buzz> In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1397 Lines: 40 On 17.07.2015 18:09, Christoph Lameter wrote: > On Fri, 17 Jul 2015, Konstantin Khlebnikov wrote: > >>> Hrm.... Bad. Maybe drop the checks for the debug options that can be >>> configured when merging slabs? They do not influence the object layout >>> per definition. >> >> I don't understand that. Debug options do changes in object layout. > > Only some debug options change the object layout and those are alrady > forbidden for caches with objects. Ah, ok. I've missed that any_slab_objects(). Never used enabling these features in runtime. > >> Since they add significant performance overhead and cannot be undone in runtime >> it's unlikely that anyone who uses them don't care about merging after that. > > Those that do not affect the object layout can be undone. Except __CMPXCHG_DOUBLE. But I guess we can use stop-machine for that. > >> Also I don't see how merging could affect debugging in positive way >> (except debugging bugs in merging logic itself). > > The problem here is that debugging is switched on for slabs that are > already merged right? > Right. And looks like problem only in conflicting sysfs names. -- Konstantin -- 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/