Re: RCU question

[Lee Revell]

On Sat, 2004-12-11 at 02:10 +0530, Dipankar Sarma wrote:
> On Fri, Dec 10, 2004 at 11:42:55AM -0800, George Anzinger wrote:
> > Dipankar Sarma wrote:
> > >And yes, RCU processing in softirq context can re-raise the softirq.
> > >AFAICS, it is perfectly normal.
> > 
> > My assumption was that, this being the idle task, RCU would be more than 
> > happy to finish all its pending tasks.
> 
> We try to avoid really long running softirqs (RCU tasklet in this case)
> for better scheduling latency. A long running rcu tasklet during
> an idle cpu may delay running of an RT process that becomes runnable
> during the rcu tasklet.
> 

Well, softirqs should really be preemptible if you care about RT task
latency.  Ingo's patches have had this for months.  Works great.  Maybe
it's time to push it upstream.

Lee

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