Re: [PATCH RT] tasklet/rt: Prevent tasklets from going into infinite spin in RT

[Mike Kravetz <kravetz@us.ibm.com>]

On Tue, Nov 29, 2011 at 10:24:31PM -0800, Mike Kravetz wrote:
> On Tue, Nov 29, 2011 at 09:50:39PM -0600, Clark Williams wrote:
> > On Tue, 29 Nov 2011 20:55:20 -0500
> > Steven Rostedt <rostedt@goodmis.org> wrote:
> > 
> > > Ingo,
> > > 
> > > I forward ported this code from 2.6.33.9-rt31, but I think you were the
> > > original author, as I found most of this code in the
> > > "tasklet-redesign.patch" from my broken out 2.6.24-rt patches. I
> > > committed it into my git tree (stable-rt) under your name, and added the
> > > Signed-off-by that you had in that patch, if you have and objections,
> > > please let me know. This patch should never see mainline, but it will
> > > probably be going into the -rt branch. I wrote up this change log, if
> > > there's something you don't like in it, let me know and I'll fix it.
> > > 
> > > Luis and Clark (I love saying that),
> > 
> > No matter how many times you say it, I'm still not treking across the
> > USA with Luis. :)
> > 
> > > I booted this patch against 3.0-rt stable, and it didn't crash ;)
> > > Could you apply it and see if it fixes the hang that you've been seeing.
> > 
> > Yeah, since Luis is a couple of time zones ahead of us, maybe it'll all
> > be fixed when we get up in the morning.
> 
> I've got it running on a system here that frequently encountered the
> condition.  I will let it perform some automated testing while I sleep.
> Should have results by morning (west coast US).

133 successful test executions (just normal reboot/restart of system).  Without
patch, system would hang/stall during restart more than 50% of the time.

-- 
Mike