svn commit: r213105 - head/sys/dev/mpt

[Marius Strobl]

On Sat, Sep 25, 2010 at 01:45:44PM +1000, Lawrence Stewart wrote:
> Hi Marius,
> 
> On 09/25/10 02:40, Marius Strobl wrote:
> > Author: marius
> > Date: Fri Sep 24 16:40:46 2010
> > New Revision: 213105
> > URL: http://svn.freebsd.org/changeset/base/213105
> > 
> > Log:
> >   Improve r56796; the reply handler actually may remove the request from
> >   the chain in which case it shouldn't be removed twice.
> >   Reported by:	Staale Kristoffersen
> 
> Can you please provide a bit of extra commentary about the symptoms of
> the issue this patch addresses? Like Staale, I'm running a FreeBSD
> server which uses mpt for its disk subsystem (SunFire X4100 with 2 x
> SATA 2.5" disks in RAID-1) and I've had a series of long running
> problems with the performance of the controller. I'm keeping a close eye
> on all mpt related commits and hope to find the cause sometime.
> 

In case the reply handler also removed the request this triggered
a sanity check in TAILQ_REMOVE with INVARIANTS compiled in, causing
a panic. I don't think it had a negative impact with INVARIANTS
disabled. Also, in order to hit the problem you first had to run
into a timeout leading to an IOC rest like here:
http://folk.uio.no/stalk/mpt/timeout.txt
i.e. I don't think this is related to your performance issue.

Marius