Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760895AbYCFWxl (ORCPT ); Thu, 6 Mar 2008 17:53:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754220AbYCFWx3 (ORCPT ); Thu, 6 Mar 2008 17:53:29 -0500 Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:54315 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755389AbYCFWx2 (ORCPT ); Thu, 6 Mar 2008 17:53:28 -0500 Date: Thu, 6 Mar 2008 14:53:11 -0800 (PST) From: Christoph Lameter X-X-Sender: clameter@schroedinger.engr.sgi.com To: Nick Piggin cc: Pekka Enberg , netdev@vger.kernel.org, Linux Kernel Mailing List , yanmin_zhang@linux.intel.com, David Miller , Eric Dumazet Subject: Re: [rfc][patch 1/3] slub: fix small HWCACHE_ALIGN alignment In-Reply-To: <20080306024904.GA27150@wotan.suse.de> Message-ID: References: <20080303200613.GC8974@wotan.suse.de> <20080303201701.GF8974@wotan.suse.de> <84144f020803031330i2c0ea1f6kc5b02c8b26145797@mail.gmail.com> <47CC6F30.50802@cs.helsinki.fi> <20080305002821.GD1510@wotan.suse.de> <20080306024904.GA27150@wotan.suse.de> 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: 832 Lines: 23 On Thu, 6 Mar 2008, Nick Piggin wrote: > > That was due to SLUB's support for smaller allocation sizes. AFAICT has > > nothing to do with alignment. > > The smaller sizes meant objects were less often aligned on cacheline > boundaries. Right since SLAB_HWCACHE_ALIGN does not align for very small objects. > We could, but I'd rather just use the flag. Do you have a case in mind where that would be useful? We had a SLAB_HWCACHE_MUST_ALIGN or so at some point but it was rarely to never used. Note that there is also KMEM_CACHE which picks up the alignment from the compiler. -- 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/