Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932729Ab1EaVyv (ORCPT ); Tue, 31 May 2011 17:54:51 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:34886 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758298Ab1EaVyu (ORCPT ); Tue, 31 May 2011 17:54:50 -0400 Date: Tue, 31 May 2011 14:54:43 -0700 From: Joel Becker To: Dan Magenheimer Cc: Steven Whitehouse , linux-kernel@vger.kernel.org, Sunil Mushran Subject: Re: Cleancache and shared filesystems Message-ID: <20110531215443.GC31742@noexit.corp.google.com> Mail-Followup-To: Dan Magenheimer , Steven Whitehouse , linux-kernel@vger.kernel.org, Sunil Mushran References: <1306504300.2857.14.camel@menhir> <6f0e746a-d3d1-4708-9e16-3d02ddeab824@default> <1306513179.2857.38.camel@menhir20110527233331.GC30232@noexit.corp.google.com> <790b3e0b-14b6-44da-9f4c-a4315b58e2c5@default> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <790b3e0b-14b6-44da-9f4c-a4315b58e2c5@default> X-Burt-Line: Trees are cool. X-Red-Smith: Ninety feet between bases is perhaps as close as man has ever come to perfection. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1647 Lines: 42 On Tue, May 31, 2011 at 07:51:36AM -0700, Dan Magenheimer wrote: > > Hey Dan, > > Steven makes a good point here. ocfs2 could also take advantage > > of local filesystem behavior when running in local mode. > > I guess the semantics need to be more clearly defined > (or perhaps changed if the shared-fs community wants), > but if cleancache_init_shared_fs is called only by > a single node, cleancache still enables all the same > functionality** as cleancache_init_fs. I don't see the ** reference in the footnotes ;-) You're saying that, for a single caller, you will properly keep the pagecache bits around in cleancache as you shrink the balloon and give them back when requested? So an ocfs2 calling cleancache_init_share_fs() in only one VM will have the same page lifetimes (including life inside cleancache but not in guest pagecache) as a similar ext3? If so, there are no changes needed at all. > I'm not sure I fully understand the semantics of > local mode though, so please clarify if you think > I am wrong or misunderstanding your point. ocfs2 local mode means that it is not a cluster filesystem. The cluster services are not enabled, and ocfs2 behaves like xfs/extN/btrfs. Joel -- "Lately I've been talking in my sleep. Can't imagine what I'd have to say. Except my world will be right When love comes back my way." http://www.jlbec.org/ jlbec@evilplan.org -- 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/