From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760907AbXFAXhk (ORCPT ); Fri, 1 Jun 2007 19:37:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754850AbXFAXhe (ORCPT ); Fri, 1 Jun 2007 19:37:34 -0400 Received: from smtp1.linux-foundation.org ([207.189.120.13]:58386 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753216AbXFAXhd (ORCPT ); Fri, 1 Jun 2007 19:37:33 -0400 Date: Fri, 1 Jun 2007 16:36:42 -0700 (PDT) From: Linus Torvalds To: Christoph Lameter cc: Andrew Morton , Jeremy Fitzhardinge , Srinivasa Ds , linux-kernel@vger.kernel.org, Srivatsa Vaddagiri , Dinakar Guniguntala , pj@sgi.com, simon.derr@bull.net, rientjes@google.com Subject: Re: [RFC] [PATCH] cpuset operations causes Badness at mm/slab.c:777 warning In-Reply-To: Message-ID: References: <465FCA79.70207@in.ibm.com> <200706011620.05756.srinivasa@in.ibm.com> <466081DE.70205@goop.org> <20070601135900.ec44b1aa.akpm@linux-foundation.org> <20070601151649.bb23c6f9.akpm@linux-foundation.org> <20070601153328.1118ccaf.akpm@linux-foundation.org> <20070601160241.33b304bf.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 1 Jun 2007, Christoph Lameter wrote: > > Hmmm... We are going rapidly here. This is a patch that I am testing right > now. It right adjust the object and the patch is manageable: No, I don't think you can do it this way. At a minimum, you'd need to test that the result is word-aligned. Preferably 8-byte aligned. We literally have stuff that knows about these things and uses the low bits in the pointer to keep extra data. (That said, I didn't check whether we actually kmalloc() the data, but I think we do - things like "struct key" etc). Now, maybe those things always have a 8-byte-aligned size, and it works out, but I'd be worried. Of course, there migth be other (even more subtle) cases where we just assume certain alignment, and depend on the fact that we just _happen_ to get it. Who knows.. Linus