Re: [patch] Real-Time Preemption, -RT-2.6.12-rc1-V0.7.41-07

Ingo Molnar
2005-03-24T17:51:49Z

* Steven Rostedt <rostedt@goodmis.org> wrote:

> > but i think i like the 'partial owner' (or rather 'owner pending')
> > technique a bit better, because it controls concurrency explicitly, and
> > it would thus e.g. allow another trick: when a new owner 'steals' a lock
> > from another in-flight task, then we could 'unwakeup' that in-flight
> > thread which could thus avoid two more context-switches on e.g. SMP
> > systems: hitting the CPU and immediately blocking on the lock. (But this
> > is a second-phase optimization which needs some core scheduler magic as
> > well, i guess i'll be the one to code it up.)
>
> Darn! It seemed like fun to implement. I may do it myself anyway on my
> kernel just to understand your implementation even better.

feel free to implement the whole thing. Unscheduling a task should be
done carefully, for obvious reasons. (I've implemented it once 1-2 years
ago for a different purpose, to unschedule ksoftirqd - it ought to be
somewhere in the lkml archives.)

Ingo