From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Subject: Re: No, really, stop trying to delete slab until you've finished making slub perform as well Date: Mon, 04 Aug 2008 16:41:16 -0500 Message-ID: <4897777C.1070801@linux-foundation.org> References: <20080801182324.572058187@lameter.com> <20080803015847.GD26461@parisc-linux.org> <4896225D.9090203@cs.helsinki.fi> <48966B6D.604@keyaccess.nl> <48977330.4090501@cs.helsinki.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Cc: Rene Herman , Matthew Wilcox , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Mel Gorman , andi@firstfloor.org, Rik van Riel To: Pekka Enberg Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:42425 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1770993AbYHDVmp (ORCPT ); Mon, 4 Aug 2008 17:42:45 -0400 In-Reply-To: <48977330.4090501@cs.helsinki.fi> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Pekka Enberg wrote: >> General interested question -- I recently "accidentally" read some of >> slub and I believe that it doesn't feature the cache colouring support >> that slab did? Is that true, and if so, wasn't it needed/useful? > > I don't know why Christoph decided not to implement it. Christoph? IMHO cache coloring issues seem to be mostly taken care of by newer more associative cpu caching designs. Note that the SLAB design origin is Solaris (See the paper by Jeff Bonwick in 1994 that is quoted in mm/slab.c). Logic for cache coloring is mostly avoided today due to the complexity it would introduce. See also http://en.wikipedia.org/wiki/CPU_cache. What one could add to support cache coloring in SLUB is a prearrangement of the order of object allocation order by constructing the initial freelist for a page in a certain way. See mm/slub.c::new_slab()