From: Martin Knoblauch <knobi@knobisoft.de>
To: linux-kernel@vger.kernel.org
Cc: Peter zijlstra <a.p.zijlstra@chello.nl>,
Fengguang Wu <wfg@mail.ustc.edu.cn>
Subject: How to find out, what "pdflush" is working on
Date: Tue, 16 Sep 2008 06:09:08 -0700 (PDT) [thread overview]
Message-ID: <849662.25086.qm@web32602.mail.mud.yahoo.com> (raw)
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
next reply other threads:[~2008-09-16 13:09 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-16 13:09 Martin Knoblauch [this message]
2008-09-16 19:07 ` How to find out, what "pdflush" is working on Chris Snook
2008-09-26 21:24 ` Frank Ch. Eigler
-- strict thread matches above, loose matches on Subject: below --
2008-09-17 8:11 Martin Knoblauch
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