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SubjectRe: RCU question
Lee Revell wrote:
> 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.

Yes, I understand, and soft_irq() does turn on interrupts...
I was thinking of something like:

while(softirq_pending()) {
local_irq_enable();
do_softirq();
local_irq_disable();
}

<proceed to idle hlt...>
--
George Anzinger george@mvista.com
High-res-timers: http://sourceforge.net/projects/high-res-timers/

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