| Date | Wed, 13 Aug 2014 10:12:15 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v5 tip/core/rcu 15/16] rcu: Make RCU-tasks wait for idle tasks |
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On Mon, Aug 11, 2014 at 03:49:04PM -0700, Paul E. McKenney wrote: > From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> > > Because idle-task code may need to be patched, RCU-tasks need to wait > for idle tasks to schedule. This commit therefore detects this case > via context switch. Block CPU hotplug during this time to avoid sending > IPIs to offline CPUs. > > Note that checking for changes in the dyntick-idle counters is tempting, > but wrong. The reason that it is wrong is that a interrupt or NMI can > increment these counters without necessarily allowing the idle tasks to > make any forward progress.
I'm going to NAK this.. with that rcu_idle patch I send there's typically only a single idle function thats out of bounds and if its more it can be made that with a bit of tlc to the cpuidle driver in question.
This needs _FAR_ more justification than a maybe and a want. [unhandled content-type:application/pgp-signature] |