Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760178AbZFKPtg (ORCPT ); Thu, 11 Jun 2009 11:49:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754376AbZFKPt3 (ORCPT ); Thu, 11 Jun 2009 11:49:29 -0400 Received: from smtp3.ultrahosting.com ([74.213.175.254]:58736 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751621AbZFKPt3 (ORCPT ); Thu, 11 Jun 2009 11:49:29 -0400 Date: Thu, 11 Jun 2009 11:49:19 -0400 (EDT) From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Pekka Enberg cc: linux-kernel@vger.kernel.org, mel@csn.ul.ie, Larry.Finger@lwfinger.net Subject: Re: [PATCH 2/2] SLUB: Disable debugging if it increases the minimum page order In-Reply-To: <1244734086.17483.59.camel@penberg-laptop> Message-ID: References: <1244728824.17483.51.camel@penberg-laptop> <1244733119.17483.56.camel@penberg-laptop> <1244734086.17483.59.camel@penberg-laptop> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1099 Lines: 26 On Thu, 11 Jun 2009, Pekka Enberg wrote: > My main point is that a lot of _testers_ will probably enable all SLUB > debugging by default because we encourage them to and it's pretty bad > that we end up causing order 1 allocations and oom conditions. Other test methods (like PAGE_ALLOC debugging) also have significant side effects. > So I still think we need to fix _at minimum_ the kmalloc-4096 case > (assuming Larry won't hit the same problem still). I see you're not > happy with my patch so any suggestions how to handle that? Add a warning to Kconfig that the higher order page allocations may increase with debugging on for caches with object sizes near or equal to PAGE_SIZE? Its good to run with full debugging on for even the 4k sized caches. Otherwise we wont be catching overruns there. But the debugging can cause some side effects. -- 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/