Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755957Ab0HXUoa (ORCPT ); Tue, 24 Aug 2010 16:44:30 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:52214 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753091Ab0HXUo2 convert rfc822-to-8bit (ORCPT ); Tue, 24 Aug 2010 16:44:28 -0400 MIME-Version: 1.0 Message-ID: <43348bbd-649d-47db-8edd-c5cb08187f19@default> Date: Tue, 24 Aug 2010 13:42:55 -0700 (PDT) From: Dan Magenheimer To: balbir@linux.vnet.ibm.com Cc: Christoph Hellwig , Boaz Harrosh , ngupta@vflare.org, akpm@linux-foundation.org, Chris Mason , viro@zeniv.linux.org.uk, Andreas Dilger , tytso@mit.edu, mfasheh@suse.com, Joel Becker , matthew@wil.cx, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, ocfs2-devel@oss.oracle.com, linux-mm@kvack.org, jeremy@goop.org, JBeulich@novell.com, Kurt Hackel , Dave Mccracken , riel@redhat.com, Konrad Wilk , Mel Gorman , Ying Han , Greg Thelen , npiggin@kernel.dk Subject: RE: cleancache followup from LSF10/MM summit References: <66336896-4396-458f-b8a5-51282a925816@default 20100824142718.GA24164@balbir.in.ibm.com> In-Reply-To: <20100824142718.GA24164@balbir.in.ibm.com> X-Priority: 3 X-Mailer: Oracle Beehive Extensions for Outlook 2.0.1.2.1.2 (406224) [OL 12.0.6535.5005] Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1341 Lines: 34 Hi Balbir -- Thanks for reviewing! > 1. Can't this be done at the MM layer - why the filesystem hooks? Is > it to enable faster block devices in the reclaim hierarchy? This is explained in FAQ #2 in: http://lkml.org/lkml/2010/6/21/411 If I misunderstood your question or the FAQ doesn't answer it, please let me know. > 2. I don't see a mention of slabcache in your approach, reclaim free > pages or freeing potentially free slab pages. Cleancache works on clean mapped pages that are reclaimed ("evicted") due to (guest) memory pressure but later would result in a refault. The decision of what pages to reclaim are left entirely to the (guest) kernel, and the "backend" (zcache or Xen tmem) dynamically decides how many clean evicted pages to retain based on dynamic factors that are unknowable to the (guest) kernel (such as compression ratios for zcache and available fallow memory for Xen tmem). I'm not sure I see how this could apply to slabcache (and I couldn't find anything in your OLS paper that refers to it), but if you have some ideas, let's discuss (offlist?). Thanks, Dan -- 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/