From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754769AbYIPNJU (ORCPT ); Tue, 16 Sep 2008 09:09:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751428AbYIPNJL (ORCPT ); Tue, 16 Sep 2008 09:09:11 -0400 Received: from web32602.mail.mud.yahoo.com ([68.142.207.229]:34287 "HELO web32602.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751203AbYIPNJK (ORCPT ); Tue, 16 Sep 2008 09:09:10 -0400 X-YMail-OSG: 0ZF8R58VM1lfUVAXQ1d3HiyqCU5HH7cQNXDcwKoZAjNJl3pzcld1KZB4XwyVFPHf5A-- X-RocketYMMF: knobi.rm X-Mailer: YahooMailRC/1096.28 YahooMailWebService/0.7.218.2 Date: Tue, 16 Sep 2008 06:09:08 -0700 (PDT) From: Martin Knoblauch Subject: How to find out, what "pdflush" is working on To: linux-kernel@vger.kernel.org Cc: Peter zijlstra , Fengguang Wu MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Message-ID: <849662.25086.qm@web32602.mail.mud.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, I find the following comment in mm/pdflush.c /* * The pdflush threads are worker threads for writing back dirty data. * Ideally, we'd like one thread per active disk spindle. But the disk * topology is very hard to divine at this level. Instead, we take * care in various places to prevent more than one pdflush thread from * performing writeback against a single filesystem. pdflush threads * have the PF_FLUSHER flag set in current->flags to aid in this. */ Is there a way to find out what a certain instance of "pdflush" is working on? Like which block-device or which fliesystem it is writing to? I am still (2.6.27) trying to track down why writing a single file can make linux very sluggish and unresponsive. If that happens I usually see all possible 8 "pdflush" threads being in "D"-state. According to above comment only one of them should be really busy. Cheers Martin ------------------------------------------------------ Martin Knoblauch email: k n o b i AT knobisoft DOT de www: http://www.knobisoft.de