Messages in this thread | | | Date | Wed, 4 Feb 2015 05:14:20 -0800 | From | "Paul E. McKenney" <> | Subject | Re: [rcu] [ INFO: suspicious RCU usage. ] |
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On Wed, Feb 04, 2015 at 01:00:18PM +0000, Russell King - ARM Linux wrote: > On Wed, Feb 04, 2015 at 12:39:07PM +0100, Krzysztof Kozlowski wrote: > > +Cc some ARM people > > I wish that people would CC this list with problems seen on ARM. I'm > minded to just ignore this message because of this in the hope that by > doing so, people will learn something... > > > > Another thing I could do would be to have an arch-specific Kconfig > > > variable that made ARM responsible for informing RCU that the CPU > > > was departing, which would allow a call to as follows to be placed > > > immediately after the complete(): > > > > > > rcu_cpu_notify(NULL, CPU_DYING_IDLE, (void *)(long)smp_processor_id()); > > > > > > Note: This absolutely requires that the rcu_cpu_notify() -always- > > > be allowed to execute!!! This will not work if there is -any- possibility > > > of __cpu_die() powering off the outgoing CPU before the call to > > > rcu_cpu_notify() returns. > > Exactly, so that's not going to be possible. The completion at that > point marks the point at which power _could_ be removed from the CPU > going down.
OK, sounds like a polling loop is required.
Thanx, Paul
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