Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932713AbXHDVt2 (ORCPT ); Sat, 4 Aug 2007 17:49:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764812AbXHDVtQ (ORCPT ); Sat, 4 Aug 2007 17:49:16 -0400 Received: from thunk.org ([69.25.196.29]:53909 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1764788AbXHDVtO (ORCPT ); Sat, 4 Aug 2007 17:49:14 -0400 Date: Sat, 4 Aug 2007 17:48:21 -0400 From: Theodore Tso To: Arjan van de Ven Cc: Linus Torvalds , =?iso-8859-1?Q?J=F6rn?= Engel , Ingo Molnar , Jeff Garzik , Peter Zijlstra , linux-mm@kvack.org, Linux Kernel Mailing List , miklos@szeredi.hu, akpm@linux-foundation.org, neilb@suse.de, dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com, trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com, richard@rsk.demon.co.uk, david@lang.hm Subject: Re: [PATCH 00/23] per device dirty throttling -v8 Message-ID: <20070804214821.GC11150@thunk.org> Mail-Followup-To: Theodore Tso , Arjan van de Ven , Linus Torvalds , =?iso-8859-1?Q?J=F6rn?= Engel , Ingo Molnar , Jeff Garzik , Peter Zijlstra , linux-mm@kvack.org, Linux Kernel Mailing List , miklos@szeredi.hu, akpm@linux-foundation.org, neilb@suse.de, dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com, trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com, richard@rsk.demon.co.uk, david@lang.hm References: <20070804103347.GA1956@elte.hu> <20070804163733.GA31001@elte.hu> <46B4C0A8.1000902@garzik.org> <20070804191205.GA24723@lazybastard.org> <20070804192130.GA25346@elte.hu> <20070804192615.GA25600@lazybastard.org> <1186258399.2777.8.camel@laptopd505.fenrus.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1186258399.2777.8.camel@laptopd505.fenrus.org> User-Agent: Mutt/1.5.13 (2006-08-11) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: tytso@thunk.org X-SA-Exim-Scanned: No (on thunker.thunk.org); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1310 Lines: 24 On Sat, Aug 04, 2007 at 01:13:19PM -0700, Arjan van de Ven wrote: > there is another trick possible (more involved though, Al will have to > jump in on that one I suspect): Have 2 types of "dirty inode" states; > one is the current dirty state (meaning the full range of ext3 > transactions etc) and "lighter" state of "atime-dirty"; which will not > do the background syncs or journal transactions (so if your machine > crashes, you lose the atime update) but it does keep atime for most > normal cases and keeps it standard compliant "except after a crash". That would make us standards compliant (POSIX explicitly says that what happens after a unclean shutdown is Unspecified) and it would make things a heck of a lot faster. However, there is a potential problem which is that it will keep a large number of inodes pinned in memory, which is its own problem. So there would have to be some way to force the atime updates to be merged when under memory pressure, and and perhaps on some much longer background interval (i.e., every hour or so). - Ted - 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/