From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935127AbXEIAvh (ORCPT ); Tue, 8 May 2007 20:51:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934594AbXEIAv3 (ORCPT ); Tue, 8 May 2007 20:51:29 -0400 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:40361 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S934586AbXEIAv2 (ORCPT ); Tue, 8 May 2007 20:51:28 -0400 Date: Tue, 8 May 2007 17:51:27 -0700 (PDT) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Matt Mackall cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: + fix-spellings-of-slab-allocator-section-in-init-kconfig.patch added to -mm tree In-Reply-To: <20070509002307.GV11115@waste.org> Message-ID: References: <200705082302.l48N2KrZ004229@shell0.pdx.osdl.net> <20070509002307.GV11115@waste.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 Tue, 8 May 2007, Matt Mackall wrote: > First, SLOB no longer runs on SMP because SLAB grew some RCU-related > hair. So it now effectively has no locks at all! Well it seems that SLOB was not well maintained. RCU has been around for a long time and SLOB has not been updated to cope with it. > Third, I don't think it's possible even in theory for a SLAB-like > allocator to be as efficient as SLOB simply due to the constraints of > putting only objects of the same size on a given page. So consider me > skeptical on the density claim. SLUB can put 32 objects sized 128 byte each in a 4k page. Can SLOB do the same? > It is usually better to use SLUB simply because you're more likely to > have 1GB of RAM rather than 4MB. SLUB should be perfectly fine for that environment provided you adjust the cacheline alignment and switch off SLUB debugging. define L1_CACHE_BYTES to be 4 or so.