From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zps35.corp.google.com (zps35.corp.google.com [172.25.146.35]) by smtp-out.google.com with ESMTP id lB4968VY032699 for ; Tue, 4 Dec 2007 01:06:08 -0800 Received: from py-out-1112.google.com (pyia29.prod.google.com [10.34.253.29]) by zps35.corp.google.com with ESMTP id lB495uJL017786 for ; Tue, 4 Dec 2007 01:06:08 -0800 Received: by py-out-1112.google.com with SMTP id a29so10408626pyi for ; Tue, 04 Dec 2007 01:06:07 -0800 (PST) Message-ID: <532480950712040106r144ed43m5cb77cc394e2ec8a@mail.gmail.com> Date: Tue, 4 Dec 2007 01:06:06 -0800 From: "Michael Rubin" Subject: Re: [patch 1/1] Writeback fix for concurrent large and small file writes In-Reply-To: <396386387.18082@ustc.edu.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20071128192957.511EAB8310@localhost> <396296481.07368@ustc.edu.cn> <532480950711291216l181b0bej17db6c42067aa832@mail.gmail.com> <396386387.18082@ustc.edu.cn> Sender: owner-linux-mm@kvack.org Return-Path: To: Fengguang Wu Cc: a.p.zijlstra@chello.nl, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Chris Mason List-ID: On Nov 29, 2007 5:32 PM, Fengguang Wu > On Nov 28, 2007 4:34 PM, Fengguang Wu wrote: > > > Could you demonstrate the situation? Or if I guess it right, could it > > > be fixed by the following patch? Feng I am sorry to have been mistaken but I reran my tests and I am now finding that the patch you gave me is NOT fixing the problem. The patch I refer to is the one you posted on this thread that adds a requeue_io in __sync_single_inode. I tarred up my test code. It is still in very rough shape but it can reproduce the issue. You can find it here: http://neverthere.org/mhr/wb/wb-test.tar.bz2 Just make the test and run it with the args "-duration 0:5:0 -starvation". You must be root so it can set some sysctl values. > One major concern could be whether a continuous writer dirting pages > at the 'right' pace will generate a steady flow of write I/Os which are > _tiny_hence_inefficient_. > > So it's not a problem in *theory* :-) > > > I will post this change for 2.6.24 and list Feng as author. If that's > > ok with Feng. I am going to try to track down what is up in 2.6.24 and see if I can find a less dramatic fix than my tree patch for the short term. If you get a chance to reproduce the problem with my test on your patch that would rock. I still would like to see my full patch accepted into 2.6.25. A patch should be arriving shortly that will incorporate my larger patch and Qi Yong's fix for skip-writing-data-pages-when-inode-is-under-i_sync. http://www.gossamer-threads.com/lists/linux/kernel/849493 As always thanks for your patience, mrubin -- 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