Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758132AbXI1I11 (ORCPT ); Fri, 28 Sep 2007 04:27:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754747AbXI1I1U (ORCPT ); Fri, 28 Sep 2007 04:27:20 -0400 Received: from wa-out-1112.google.com ([209.85.146.180]:61939 "EHLO wa-out-1112.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753659AbXI1I1T (ORCPT ); Fri, 28 Sep 2007 04:27:19 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=LsojLKYSUIgVYFRYRuJ1l9l+Yg3MUxo8YuS2zBx67wwCCLZ1D+31qyjv244Ng2/ePOY+a/IpInwgrXqm9sPUegGEr8oERSfFoFr+oD8tjMK+LxoGmpdbVpb3dncq1gYs2VxwxJpnyNCacIQJmria2+aTS5ZhvehHhKN5Gr5QSy4= Message-ID: <92cbf19b0709280127yba48b60wfe58e532944894ca@mail.gmail.com> Date: Fri, 28 Sep 2007 01:27:18 -0700 From: "Chakri n" To: "Peter Zijlstra" Subject: Re: A unresponsive file system can hang all I/O in the system on linux-2.6.23-rc6 (dirty_thresh problem?) Cc: "Andrew Morton" , linux-pm , lkml , nfs@lists.sourceforge.net In-Reply-To: <1190962752.31636.15.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <92cbf19b0709272332s25684643odaade0e98cb3a1f4@mail.gmail.com> <20070927235034.ae7bd73d.akpm@linux-foundation.org> <1190962752.31636.15.camel@twins> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1625 Lines: 49 Thanks. The BDI dirty limits sounds like a good idea. Is there already a patch for this, which I could try? I believe it works like this, Each BDI, will have a limit. If the dirty_thresh exceeds the limit, all the I/O on the block device will be synchronous. so, if I have sda & a NFS mount, the dirty limit can be different for each of them. I can set dirty limit for - sda to be 90% and - NFS mount to be 50%. So, if the dirty limit is greater than 50%, NFS does synchronously, but sda can work asynchronously, till dirty limit reaches 90%. Thanks --Chakri On 9/27/07, Peter Zijlstra wrote: > On Thu, 2007-09-27 at 23:50 -0700, Andrew Morton wrote: > > > What we _don't_ want to happen is for other processes which are writing to > > other, non-dead devices to get collaterally blocked. We have patches which > > might fix that queued for 2.6.24. Peter? > > Nasty problem, don't do that :-) > > But yeah, with per BDI dirty limits we get stuck at whatever ratio that > NFS server/mount (?) has - which could be 100%. Other processes will > then work almost synchronously against their BDIs but it should work. > > [ They will lower the NFS-BDI's ratio, but some fancy clipping code will > limit the other BDIs their dirty limit to not exceed the total limit. > And with all these NFS pages stuck, that will still be nothing. ] > > > > - 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/