Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753505Ab2JMNxN (ORCPT ); Sat, 13 Oct 2012 09:53:13 -0400 Received: from mail-vb0-f46.google.com ([209.85.212.46]:52241 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752218Ab2JMNxL (ORCPT ); Sat, 13 Oct 2012 09:53:11 -0400 MIME-Version: 1.0 In-Reply-To: <3D1C85A52BB960B79E37AC30@nimrod.local> References: <0B138F62-16BF-4295-9AD9-64C0BB39FCE2@alex.org.uk> <20121012133044.GA10115@dhcp22.suse.cz> <20121012145838.GD22083@dhcp22.suse.cz> <3D1C85A52BB960B79E37AC30@nimrod.local> Date: Sat, 13 Oct 2012 21:53:09 +0800 Message-ID: Subject: Re: Local DoS through write heavy I/O on CFQ & Deadline From: Hillf Danton To: Alex Bligh Cc: LKML Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 792 Lines: 25 Hi Alex, On Sat, Oct 13, 2012 at 12:29 AM, Alex Bligh wrote: > Michael, > > --On 12 October 2012 16:58:39 +0200 Michal Hocko wrote: > >> Once dirty_ratio (resp. dirty_bytes) limit is hit then the process which >> writes gets throttled. If this is not the case then there is a bug in >> the throttling code. > > > I believe that is the problem. Take a look at the "wait for writeback" problem please. Linux 3.0+ Disk performance problem - wrong pdflush behaviour https://lkml.org/lkml/2012/10/10/412 Hillf -- 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/