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From: Mike Galbraith <efault@gmx.de>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Chris Mason <chris.mason@fusionio.com>,
	"Chris L. Mason" <clmason@fusionio.com>,
	"linux-rt-users@vger.kernel.org" <linux-rt-users@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: 3.4.4-rt13: btrfs + xfstests 006 = BOOM..  and a bonus rt_mutex deadlock report for absolutely free!
Date: Mon, 16 Jul 2012 18:36:07 +0200	[thread overview]
Message-ID: <1342456567.7659.97.camel@marge.simpson.net> (raw)
In-Reply-To: <1342455968.7659.93.camel@marge.simpson.net>

On Mon, 2012-07-16 at 18:26 +0200, Mike Galbraith wrote: 
> On Mon, 2012-07-16 at 12:02 -0400, Steven Rostedt wrote: 
> > On Mon, 2012-07-16 at 04:02 +0200, Mike Galbraith wrote:
> > 
> > > > Great, thanks!  I got stuck in bug land on Friday.  You mentioned
> > > > performance problems earlier on Saturday, did this improve performance?
> > > 
> > > Yeah, the read_trylock() seems to improve throughput.  That's not
> > > heavily tested, but it certainly looks like it does.  No idea why.
> > 
> > Ouch, you just turned the rt_read_lock() into a spin lock. If a higher
> > priority process preempted a lower priority process that holds the same
> > lock, it will deadlock.
> 
> Hm, how, it's doing cpu_chill()?

'course PI is toast, so *poof*.  Since just enabling the lockdep bits
seems to fix it up, maybe that's the patchlet to submit (less is more).

-Mike


  parent reply	other threads:[~2012-07-16 16:36 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-12  5:47 3.4.4-rt13: btrfs + xfstests 006 = BOOM.. and a bonus rt_mutex deadlock report for absolutely free! Mike Galbraith
2012-07-12  8:44 ` Mike Galbraith
2012-07-12  9:53   ` Mike Galbraith
2012-07-12 11:43     ` Thomas Gleixner
2012-07-12 11:57       ` Mike Galbraith
2012-07-12 13:31         ` Thomas Gleixner
2012-07-12 13:37           ` Mike Galbraith
2012-07-12 13:43             ` Thomas Gleixner
2012-07-12 13:48               ` Mike Galbraith
2012-07-12 13:51                 ` Mike Galbraith
2012-07-13  6:31           ` Mike Galbraith
2012-07-13  9:52             ` Thomas Gleixner
2012-07-13 10:14               ` Mike Galbraith
2012-07-13 10:26                 ` Thomas Gleixner
2012-07-13 10:47                   ` Chris Mason
2012-07-13 12:50                     ` Mike Galbraith
2012-07-12 11:07 ` Thomas Gleixner
2012-07-12 17:09   ` Chris Mason
2012-07-13 10:04     ` Thomas Gleixner
2012-07-13 12:50 ` Chris Mason
2012-07-13 14:47   ` Thomas Gleixner
2012-07-14 10:14   ` Mike Galbraith
2012-07-15 17:56     ` Chris Mason
2012-07-16  2:02       ` Mike Galbraith
2012-07-16 16:02         ` Steven Rostedt
2012-07-16 16:26           ` Mike Galbraith
2012-07-16 16:35             ` Chris Mason
2012-07-16 16:36             ` Mike Galbraith [this message]
2012-07-16 17:03               ` Steven Rostedt
2012-07-17  4:18                 ` Mike Galbraith
2012-07-17  4:27                   ` Steven Rostedt
2012-07-17  4:34                     ` Steven Rostedt
2012-07-17  4:46                       ` Mike Galbraith
2012-07-17  4:44                     ` Mike Galbraith
2012-07-17 12:54                   ` Mike Galbraith
2012-07-16 10:55     ` Mike Galbraith
2012-07-16 15:43       ` Chris Mason
2012-07-16 16:16         ` Mike Galbraith
2012-07-14 13:38   ` Mike Galbraith

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