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Date: Mon, 3 Aug 2009 15:56:17 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Chris Mason <chris.mason@oracle.com>, Roland Dreier <rdreier@cisco.com>,
       Frederic Weisbecker <fweisbec@gmail.com>,
       Andi Kleen <andi@firstfloor.org>, LKML <linux-kernel@vger.kernel.org>,
       Jeff Mahoney <jeffm@suse.com>,
       Alexander Beregalov <a.beregalov@gmail.com>,
       Bron Gondwana <brong@fastmail.fm>,
       Reiserfs <reiserfs-devel@vger.kernel.org>,
       Al Viro <viro@zeniv.linux.org.uk>,
       Andrea Gelmini <andrea.gelmini@gmail.com>,
       "Trenton D. Adams" <trenton.d.adams@gmail.com>,
       Thomas Meyer <thomas@m3y3r.de>,
       Alessio Igor Bogani <abogani@texware.it>,
       Marcel Hilzinger <mhilzinger@linuxnewmedia.de>,
       Edward Shishkin <edward.shishkin@gmail.com>
Subject: Re: [ANNOUNCE] Reiserfs/kill-bkl tree v2
Message-ID: <20090803135617.GB15020@elte.hu>
References: <20090731174642.GA6539@nowhere> <20090801081141.GA18036@basil.fritz.box> <20090801155335.GA4836@nowhere> <20090802142100.GA21160@elte.hu> <adatz0po5cn.fsf@cisco.com> <20090803132659.GC3570@think>
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* Chris Mason <chris.mason@oracle.com> wrote:

> Definitely, the cost of the rare bug is much higher.  The good 
> news is that reiserfs tends to pile its races into a few spots.  
> Most of them can be found with a 12 hour run of the namesys 
> stress.sh program and a lot of memory pressure.  I'd compile with 
> preemption on and you'll have a good test on any SMP machine.
> 
> http://oss.oracle.com/~mason/stress.sh
> 
> stress.sh just copies a source directory into the test filesystem, 
> then reads it back and deletes it in a loop.  I'd run with 50 
> procs and enough memory pressure for the box to lightly swap 
> (booting w/mem= is a fine way to make memory pressure).  This way 
> you make sure to hammer on the metadata writeback paths, which is 
> where all of the difficult races come in.
> 
> Testing with an fsx-linux process running at the same time will 
> make sure all of the mmap/truncate paths are working correctly as 
> well.

Ok, that definitely looks like something feasible to run for 
Frederic too, thanks for the detailed suggestion!

	Ingo