cpuidle:(POWER) Fixes for pseries_idle hotplug notifier From: Deepthi Dharwar <deep...@linux.vnet.ibm.com>
Currently the call to pseries_notify_cpuidle_add_cpu(), that takes action on the cpuidle front when a cpu is added/removed is being made from smp_xics_setup_cpu(). This caused lockdep issues as reported https://lkml.org/lkml/2012/5/17/2 On addition of each cpu, resources were cleared and re-allocated each time, all in critical section as part of start_secondary() call were interrupts are disabled. To resolve this issue, the pseries_notify_cpuidle_add_cpu() call is is being replaced by a hotplug notifier which would prevent cpuidle resources from being released and allocated each time cpu is onlined in the critical code path. It was fixed in https://lkml.org/lkml/2012/5/18/174. Also it is essential to call cpuidle_enable/disable_device between cpuidle_pause_and_lock() and cpuidle_resume_and_unlock() when used externally to avoid race conditions. Add support for CPU_ONLINE_FROZEN and CPU_DEAD_FROZEN as part of hotplug notify event for pseries_idle and unregister hotplug notifier while exiting out. The above mentioned issues are fixed as part of this patch. Signed-off-by: Deepthi Dharwar <deep...@linux.vnet.ibm.com> --- This applies on 3.5-rc5. arch/powerpc/platforms/pseries/processor_idle.c | 23 ++++++++++++++++++----- 1 files changed, 18 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c index a97ef66..d2d2d85 100644 --- a/arch/powerpc/platforms/pseries/processor_idle.c +++ b/arch/powerpc/platforms/pseries/processor_idle.c @@ -194,13 +194,25 @@ static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n, struct cpuidle_device *dev = per_cpu_ptr(pseries_cpuidle_devices, hotcpu); - switch (action & 0xf) { - case CPU_ONLINE: - if (dev && cpuidle_get_driver()) { - cpuidle_disable_device(dev); + if (dev && cpuidle_get_driver()) { + switch (action) { + case CPU_ONLINE: + case CPU_ONLINE_FROZEN: + cpuidle_pause_and_lock(); cpuidle_enable_device(dev); + cpuidle_resume_and_unlock(); + break; + + case CPU_DEAD: + case CPU_DEAD_FROZEN: + cpuidle_pause_and_lock(); + cpuidle_disable_device(dev); + cpuidle_resume_and_unlock(); + break; + + default: + return NOTIFY_DONE; } - break; } return NOTIFY_OK; } @@ -342,6 +354,7 @@ static int __init pseries_processor_idle_init(void) static void __exit pseries_processor_idle_exit(void) { + unregister_cpu_notifier(&setup_hotplug_notifier); pseries_idle_devices_uninit(); cpuidle_unregister_driver(&pseries_idle_driver); Cheers, Deepthi _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
