Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933392AbXBXF3j (ORCPT ); Sat, 24 Feb 2007 00:29:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933393AbXBXF3j (ORCPT ); Sat, 24 Feb 2007 00:29:39 -0500 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:48074 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933392AbXBXF3i (ORCPT ); Sat, 24 Feb 2007 00:29:38 -0500 Date: Sat, 24 Feb 2007 14:28:35 +0900 From: KAMEZAWA Hiroyuki To: Christoph Lameter Cc: andi@firstfloor.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: SLUB: The unqueued Slab allocator Message-Id: <20070224142835.4c7a3207.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: Organization: Fujitsu X-Mailer: Sylpheed version 2.2.0 (GTK+ 2.6.10; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1078 Lines: 27 On Thu, 22 Feb 2007 10:42:23 -0800 (PST) Christoph Lameter wrote: > > > G. Slab merging > > > > > > We often have slab caches with similar parameters. SLUB detects those > > > on bootup and merges them into the corresponding general caches. This > > > leads to more effective memory use. > > > > Did you do any tests on what that does to long term memory fragmentation? > > It is against the "object of same type have similar livetime and should > > be clustered together" theory at least. > > I have done no tests in that regard and we would have to assess the impact > that the merging has to overall system behavior. > >From a viewpoint of a crash dump user, this merging will make crash dump investigation very very very difficult. So please avoid this merging if the benefit is nog big. -Kame - 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/