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

Ingo Molnar
2005-03-24T18:18:56Z

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

> On an SMP machine, there may even be a chance of a lower priority
> process that gets it. That would be possible if the low priority
> process on the other CPU tries to grab the lock just after it was
> released but before the just woken up high priorty processes get
> scheduled. So there's a window where the lock is open, and the lower
> priority process snagged it just before the others got in.

that's always a possibility, on UP too: if a lower priority task manages
to acquire a lock 'just before' a highprio thread got interested in it
there's no way to undo that.

but for the other reasons the explicit approach looks better.

Ingo