scheduler (sched_4bsd) questions

[John Baldwin]

On Saturday 18 September 2004 01:42 pm, Stephan Uphoff wrote:
> On Fri, 2004-09-17 at 21:20, Julian Elischer wrote:
> > Stephan Uphoff wrote:
> > >If this is true kernel threads can be preempted while holding
> > >for example the root vnode lock (or other important kernel
> > >resources) while not getting a chance to run until there are no more
> > >user processes with better priority.
> >
> > This is also true,  though it is a slightly more complicated thing than
> > that.
> > Preempting threads are usually interrupt threads and are thus usually
> > short lived,.
>
> But interrupt threads often wake up other threads ...

That are lower priority and thus won't be preempted to.  Instead, they run 
when the interrupt thread goes back to sleep after it finishes.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org