From: Jamie Lokier Subject: Re: No, really, stop trying to delete slab until you've finished making slub perform as well Date: Mon, 4 Aug 2008 16:21:46 +0100 Message-ID: <20080804152146.GG18868@shareable.org> References: <20080801182324.572058187@lameter.com> <20080803015847.GD26461@parisc-linux.org> <48970779.80902@linux-foundation.org> <20080804144823.GE18868@shareable.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Matthew Wilcox , Pekka Enberg , akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Mel Gorman , andi@firstfloor.org, Rik van Riel To: Christoph Lameter Return-path: Received: from mail2.shareable.org ([80.68.89.115]:47044 "EHLO mail2.shareable.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755021AbYHDPVw (ORCPT ); Mon, 4 Aug 2008 11:21:52 -0400 Content-Disposition: inline In-Reply-To: <20080804144823.GE18868@shareable.org> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Jamie Lokier wrote: > Vaguely on this topic, has anyone studied the effects of SLAB/SLUB > etc. on MMUless systems? The reason is that MMU-less systems are extremely sensitive to fragmentation. Every program started on those systems must allocate a large contiguous block for the code and data, and every malloc >1 page is the same. If memory is too fragmented, starting new programs fails. The high-order page-allocator defragmentation lately should help with that. The different behaviours of SLAB/SLUB might result in different levels of fragmentation, so I wonder if anyone has compared them on MMU-less systems or fragmentation-sensitive workloads on general systems. Thanks, -- Jamie