Re: [PATCH] stopmachine: add stopmachine_timeout

On Tuesday 15 July 2008 12:24:54 Max Krasnyansky wrote:

Heiko Carstens wrote:

quoted

On Mon, Jul 14, 2008 at 11:56:18AM -0700, Jeremy Fitzhardinge wrote:
This is asking for trouble... a config option to disable this would be
nice. But as I don't know which problem this patch originally addresses
it might be that this is needed anyway. So lets see why we need it first.

How about this. We'll make this a sysctl, as Rusty already did, and set the
default to 0 which means "never timeout". That way crazy people like me who
care about this scenario can enable this feature.

Indeed, this was my thought too.  s390 can initialize it to zero somewhere in 
their boot code.

btw Rusty, I just had this "why didn't I think of that" moments. This is
actually another way of handling my workload. I mean it certainly does not
fix the root case of the problems and we still need other things that we
talked about (non-blocking module delete, lock-free module insertion, etc)
but at least in the mean time it avoids wedging the machines for good.
btw I'd like that timeout in milliseconds. I think 5 seconds is way tooooo
long :).

We can make it ms, sure.  200ms should be plenty of time: worst I ever saw was 
150ms, and that was some weird Power box doing crazy stuff.  I wouldn't be 
surprised if you'd never see 1ms on your hardware.

The ipi idea would handle your case a little more nicely, too, but that's 
probably not going to hit this merge window.

Cheers,
Rusty.