Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754624AbZJDMIh (ORCPT ); Sun, 4 Oct 2009 08:08:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754141AbZJDMIg (ORCPT ); Sun, 4 Oct 2009 08:08:36 -0400 Received: from fg-out-1718.google.com ([72.14.220.155]:58651 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753647AbZJDMIf (ORCPT ); Sun, 4 Oct 2009 08:08:35 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; b=MnNJtHC4xg+ozD4cfklqOgPTCuNfWijW9R0dG6efbxTMCUOGTB0Qc5nahsJOpQQGE0 3K5Rk2NxZTnAh4VjgyeSMYL76hKT86WzyTak0SD2kp25Oe/N5+TcZBBQn8T2xKcAcqB/ e47r25QGWICG92KC+ug1hi4h79OAc02uYzBbY= MIME-Version: 1.0 In-Reply-To: References: <1253624054-10882-1-git-send-email-mel@csn.ul.ie> <1253624054-10882-3-git-send-email-mel@csn.ul.ie> <84144f020909220638l79329905sf9a35286130e88d0@mail.gmail.com> <20090922135453.GF25965@csn.ul.ie> <84144f020909221154x820b287r2996480225692fad@mail.gmail.com> <20090922185608.GH25965@csn.ul.ie> <20090930144117.GA17906@csn.ul.ie> <20090930220541.GA31530@csn.ul.ie> Date: Sun, 4 Oct 2009 15:06:45 +0300 X-Google-Sender-Auth: 800c20bb7bbf5b69 Message-ID: <84144f020910040506l24a74660s508c828123c554cc@mail.gmail.com> Subject: Re: [PATCH 2/4] slqb: Record what node is local to a kmem_cache_cpu From: Pekka Enberg To: Christoph Lameter Cc: Mel Gorman , Nick Piggin , heiko.carstens@de.ibm.com, sachinp@in.ibm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Tejun Heo , Benjamin Herrenschmidt Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2198 Lines: 43 On Thu, Oct 1, 2009 at 2:45 AM, Christoph Lameter wrote: >> This is essentially the "unqueued" nature of SLUB. It's objective "I have this >> page here which I'm going to use until I can't use it no more and will depend >> on the page allocator to sort my stuff out". I have to read up on SLUB up >> more to see if it's compatible with SLQB or not though. In particular, how >> does SLUB deal with frees from pages that are not the "current" page? SLQB >> does not care what page the object belongs to as long as it's node-local >> as the object is just shoved onto a LIFO for maximum hotness. > > Frees are done directly to the target slab page if they are not to the > current active slab page. No centralized locks. Concurrent frees from > processors on the same node to multiple other nodes (or different pages > on the same node) can occur. > >> > SLAB deals with it in fallback_alloc(). It scans the nodes in zonelist >> > order for free objects of the kmem_cache and then picks up from the >> > nearest node. Ugly but it works. SLQB would have to do something similar >> > since it also has the per node object bins that SLAB has. >> > >> >> In a real sense, this is what the patch ends up doing. When it fails to >> get something locally but sees that the local node is memoryless, it >> will check the remote node lists in zonelist order. I think that's >> reasonable behaviour but I'm biased because I just want the damn machine >> to boot again. What do you think? Pekka, Nick? > > Look at fallback_alloc() in slab. You can likely copy much of it. It > considers memory policies and cpuset constraints. Sorry for the delay. I went ahead and merged Mel's patch to make things boot on PPC. Fallback policy needs a bit more work as Christoph says but I'd really love to have Nick's input on this. Mel, do you have a Kconfig patch laying around somewhere to enable SLQB on PPC and S390? Pekka -- 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/