From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <46BBAF82.7020702@tmr.com> Date: Thu, 09 Aug 2007 20:21:22 -0400 From: Bill Davidsen MIME-Version: 1.0 Subject: Re: [PATCH 00/23] per device dirty throttling -v8 References: <20070804070737.GA940@elte.hu> <20070804103347.GA1956@elte.hu> <20070804163733.GA31001@elte.hu> <46B4C0A8.1000902@garzik.org> <20070804191205.GA24723@lazybastard.org> <20070804192130.GA25346@elte.hu> <20070804192615.GA25600@lazybastard.org> <20070804194259.GA25753@lazybastard.org> <20070805203602.GB25107@infradead.org> <46BA3137.3020701@mbligh.org> <20070808142146.c85ab8d7.akpm@linux-foundation.org> In-Reply-To: <20070808142146.c85ab8d7.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: "Martin J. Bligh" , Christoph Hellwig , J??rn Engel , Ingo Molnar , Jeff Garzik , Linus Torvalds , Peter Zijlstra , linux-mm@kvack.org, Linux Kernel Mailing List , miklos@szeredi.hu, 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 List-ID: Andrew Morton wrote: > On Wed, 08 Aug 2007 14:10:15 -0700 > "Martin J. Bligh" wrote: > >> Why isn't this easily fixable by just adding an additional dirty >> flag that says atime has changed? Then we only cause a write >> when we remove the inode from the inode cache, if only atime >> is updated. > > I think that could be made to work, and it would fix the performance > issue. > > It is a behaviour change. At present ext3 (for example) commits everything > every five seconds. After a change like this, a crash+recovery could cause > a file's atime to go backwards by an arbitrarily large time interval - it > could easily be months. > I would think that (really) updating atime on open would be enough, hopefully without being too much. The "lazyatime" thing I was playing with only updated on open, final close, write, and fork. I like the idea of updating once in a while, but one of the benefits of noatime is allowing drives to spin down via inactivity. If something does get done in the area of less but non-zero atime tracking, perhaps that could be taken into account. I have to check what "laptop_mode actually does, since my laptops are old installs. -- Bill Davidsen "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org