Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-04-02 Thread Peter Zijlstra
On Thu, Apr 02, 2015 at 02:12:47PM +0200, Ingo Molnar wrote: > Okay. I'll resurrect the fix with a hotplug_cpu__tick_pull() name - > agreed? Sure. > > > Also, I improved the changelog (attached below), but decided > > > against applying it until these questions are cleared - please use > > > t

Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-04-02 Thread Preeti U Murthy
On 04/02/2015 05:42 PM, Ingo Molnar wrote: > > * Peter Zijlstra wrote: > >> On Thu, Apr 02, 2015 at 12:42:27PM +0200, Ingo Molnar wrote: >>> So why not use a suitable CPU_DOWN* notifier for this, instead of open >>> coding it all into a random place in the hotplug machinery? >> >> Because notif

Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-04-02 Thread Ingo Molnar
* Peter Zijlstra wrote: > On Thu, Apr 02, 2015 at 12:42:27PM +0200, Ingo Molnar wrote: > > So why not use a suitable CPU_DOWN* notifier for this, instead of open > > coding it all into a random place in the hotplug machinery? > > Because notifiers are crap? ;-) [...] No doubt - but I didn't f

Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-04-02 Thread Peter Zijlstra
On Thu, Apr 02, 2015 at 12:42:27PM +0200, Ingo Molnar wrote: > So why not use a suitable CPU_DOWN* notifier for this, instead of open > coding it all into a random place in the hotplug machinery? Because notifiers are crap? ;-) Its entirely impossible to figure out what's happening to core code i

Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-04-02 Thread Preeti U Murthy
On 04/02/2015 05:01 PM, Ingo Molnar wrote: > > * Preeti U Murthy wrote: > >> On 04/02/2015 04:12 PM, Ingo Molnar wrote: >>> >>> * Preeti U Murthy wrote: >>> It was found when doing a hotplug stress test on POWER, that the machine either hit softlockups or rcu_sched stall warnings. Th

Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-04-02 Thread Ingo Molnar
* Preeti U Murthy wrote: > On 04/02/2015 04:12 PM, Ingo Molnar wrote: > > > > * Preeti U Murthy wrote: > > > >> It was found when doing a hotplug stress test on POWER, that the machine > >> either hit softlockups or rcu_sched stall warnings. The issue was > >> traced to commit 7cba160ad789a

Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-04-02 Thread Preeti U Murthy
On 04/02/2015 04:12 PM, Ingo Molnar wrote: > > * Preeti U Murthy wrote: > >> It was found when doing a hotplug stress test on POWER, that the machine >> either hit softlockups or rcu_sched stall warnings. The issue was >> traced to commit 7cba160ad789a powernv/cpuidle: Redesign idle states >> m

Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-04-02 Thread Ingo Molnar
* Preeti U Murthy wrote: > It was found when doing a hotplug stress test on POWER, that the machine > either hit softlockups or rcu_sched stall warnings. The issue was > traced to commit 7cba160ad789a powernv/cpuidle: Redesign idle states > management, which exposed the cpu down race with hrtim

Re: [PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-03-30 Thread Nicolas Pitre
On Mon, 30 Mar 2015, Preeti U Murthy wrote: > It was found when doing a hotplug stress test on POWER, that the machine > either hit softlockups or rcu_sched stall warnings. The issue was > traced to commit 7cba160ad789a powernv/cpuidle: Redesign idle states > management, which exposed the cpu dow

[PATCH V2] clockevents: Fix cpu down race for hrtimer based broadcasting

2015-03-30 Thread Preeti U Murthy
It was found when doing a hotplug stress test on POWER, that the machine either hit softlockups or rcu_sched stall warnings. The issue was traced to commit 7cba160ad789a powernv/cpuidle: Redesign idle states management, which exposed the cpu down race with hrtimer based broadcast mode(Commit 5d163