Re: Why can't I set the priority of softirq-hrt? (Re: 2.6.17-rt1)

From: Thomas Gleixner
Date: Tue Jun 20 2006 - 16:32:51 EST


On Tue, 2006-06-20 at 22:16 +0100, Esben Nielsen wrote:
> > We had this before and it is horrible.
>
> "Horrible" in what respect?

Unbound latencies.

> > A nice solution would be to enqueue the timer into the task struct of
> > the thread which is target of the signal, wake that thread in a special
> > state which only runs the callback and then does the signal delivery.
>
> What if the thread is running?

Well, do it in the return from interrupt path.

> Hmm, a practical thing to do would be to make a system where you can post
> jobs in a thread. These jobs can then be done in thread context
> around schedule or just before the task returns to user-space.

Thats basically what I said. But you have to take care of asynchronous
signal delivery. Therefor you need a special state. Also return to
userspace is not enough. You have to do the check in the return from
interrupt path, as you might delay async signals otherwise.

tglx


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