Messages in this thread | | | Date | Sat, 11 Dec 2004 02:10:03 +0530 | From | Dipankar Sarma <> | Subject | Re: RCU question |
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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.
> > It may be necessary for me to rethink the conditions required to go into > the VST state. I had assumed that it required NO softirq pending as a pre > condition. From this point on we would have the interrupt system off until > the hardware sleep instruction (hlt in the x86 case).
Unfortunately, we aren't there yet. But it is in my TODO list for a generic nohz system.
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