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To: Chris Snook <csnook@redhat.com>
Cc: Martin Knoblauch <knobi@knobisoft.de>, linux-kernel@vger.kernel.org,
       Peter zijlstra <a.p.zijlstra@chello.nl>,
       Fengguang Wu <wfg@mail.ustc.edu.cn>, systemtap@sources.redhat.com
Subject: Re: How to find out, what "pdflush" is working on
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	<48D003F1.50101@redhat.com>
From: fche@redhat.com (Frank Ch. Eigler)
Date: Fri, 26 Sep 2008 17:24:41 -0400
In-Reply-To: <48D003F1.50101@redhat.com> (Chris Snook's message of "Tue, 16 Sep 2008 15:07:29 -0400")
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> [...]
>> 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? [...]

Something based upon the following systemtap script may help:

probe kernel.function("__writeback_single_inode") {
  if (execname() == "pdflush")
     printf("pdflush %d writeback bdev %x inode %x\n", tid(), $inode->i_rdev, $inode->i_ino) 
}

Other fields are available as $inode->FOO.

- FChE