On 02/17/2015 04:09 PM, Peter Zijlstra wrote: >> [PATCH 11/35] clockevents: Cleanup dead cpu explicitely n Tue, Feb 17, 2015 at 09:33:45AM +0530, Preeti U Murthy wrote: >> On 02/16/2015 05:45 PM, Peter Zijlstra wrote: >> >>>> From: Thomas Gleixner <[email protected]> >> >>>> @@ -428,7 +428,7 @@ static int __ref _cpu_down(unsigned int >>>> __cpu_die(cpu); >>>> >>>> /* CPU is completely dead: tell everyone. Too late to complain. */ >>>> - tick_cleanup_dead_cpu(cpu); >>>> + tick_takeover(cpu); >> >> Why is tick_handover() called after __cpu_die()?
> See: [PATCH 11/35] clockevents: Cleanup dead cpu explicitely > it used to be a CPU_DEAD notifier. > But, I think, the actual reason would be that you cannot be sure its not > still ticking until its actually proper dead and buried, so trying to > take over a tick from a cpu that's still ticking is... well, suspect. Look at the changelog, it explains why tick_takeover must be called *before* __cpu_die(). The above hunk is not solving the issue, it is equivalent to the scenario where we took over broadcast duty in the CPU_DEAD phase as a consequence of which the cpu doing the hotplug operation is stuck sleeping forever. Cleanup functions can be handled after __cpu_die() for the reason that you mention above. Regards Preeti U Murthy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
