Messages in this thread | | | Date | Fri, 22 Nov 2013 09:17:27 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 3/7] idle, thermal, acpi: Remove home grown idle implementations |
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On Fri, Nov 22, 2013 at 12:33:00PM +0100, Peter Zijlstra wrote: > On Thu, Nov 21, 2013 at 08:20:36PM -0800, Paul E. McKenney wrote: > > The 6ms to 25ms range should be just fine as far as normal RCU grace > > periods are concerned. However, it does mean that expedited grace > > periods could be delayed: They normally take a few tens of microseconds, > > but if they were unlucky enough to show up during an idle injection, > > they would be magnified by two to three orders of magnitude, which is > > not pretty. > > > > Hence my suggestion of hooking into RCU on idle-injection start and end > > so that RCU considers that time period to be idle. Just like it does > > for user-mode execution on NO_HZ_FULL kernels, so I still don't see this > > approach to be a problem. I must confess that I still don't understand > > what Arjan doesn't like about it. > > Using these patches it would indeed use the RCU idle machinery as per > the normal idle path.
OK, sorry for my confusion!
> If you can I can add more WARN_ON()s in play_idle() to ensure we're not > called while holding any RCU locks.
An rcu_sleep_check() or something similar, please!
Thanx, Paul
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