From: Deepthi Dharwar Date: Tue, 3 Jul 2012 20:07:22 +0000 (+0000) Subject: powerpc/cpuidle: Fixes for pseries_idle hotplug notifier X-Git-Tag: next-20120724~105^2~15 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=852d8cb1ff7cc26e59a4bbb68e230d133b257098;p=karo-tx-linux.git powerpc/cpuidle: Fixes for pseries_idle hotplug notifier 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 Signed-off-by: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c index 7f5668b94165..455760b1fe6e 100644 --- a/arch/powerpc/platforms/pseries/processor_idle.c +++ b/arch/powerpc/platforms/pseries/processor_idle.c @@ -197,13 +197,25 @@ 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; } @@ -345,6 +357,7 @@ 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);