Messages in this thread Patch in this message | | | Date | Fri, 18 May 2012 18:58:58 +0530 | From | Deepthi Dharwar <> | Subject | [PATCH] cpuidle: (POWER) Replace pseries_notify_cpuidle_add call with a elegant notifier to fix lockdep problem in start_secondary |
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The following patch is to remove the pseries_notify_add_cpu() call and replace it by a hot plug notifier. This would prevent cpuidle resources being released and allocated each time cpu comes online on pseries. The earlier design was causing a lockdep problem in start_secondary as reported on this thread -https://lkml.org/lkml/2012/5/17/2
This applies on 3.4-rc7
Signed-off-by: Deepthi Dharwar <deepthi@linux.vnet.ibm.com> --- arch/powerpc/include/asm/processor.h | 2 -- arch/powerpc/platforms/pseries/processor_idle.c | 25 +++++++++++++++++------ arch/powerpc/platforms/pseries/smp.c | 1 - 3 files changed, 19 insertions(+), 9 deletions(-)
diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index 8e2d037..c6bc22b 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -390,10 +390,8 @@ void cpu_idle_wait(void);
#ifdef CONFIG_PSERIES_IDLE extern void update_smt_snooze_delay(int snooze); -extern int pseries_notify_cpuidle_add_cpu(int cpu); #else static inline void update_smt_snooze_delay(int snooze) {} -static inline int pseries_notify_cpuidle_add_cpu(int cpu) { return 0; } #endif
extern void flush_instruction_cache(void); diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c index 41a34bc..d1a7dc0 100644 --- a/arch/powerpc/platforms/pseries/processor_idle.c +++ b/arch/powerpc/platforms/pseries/processor_idle.c @@ -11,6 +11,7 @@ #include <linux/moduleparam.h> #include <linux/cpuidle.h> #include <linux/cpu.h> +#include <linux/notifier.h>
#include <asm/paca.h> #include <asm/reg.h> @@ -186,17 +187,28 @@ static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { .enter = &shared_cede_loop }, };
-int pseries_notify_cpuidle_add_cpu(int cpu) +static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n, + unsigned long action, void *hcpu) { + int hotcpu = (unsigned long)hcpu; struct cpuidle_device *dev = - per_cpu_ptr(pseries_cpuidle_devices, cpu); - if (dev && cpuidle_get_driver()) { - cpuidle_disable_device(dev); - cpuidle_enable_device(dev); + per_cpu_ptr(pseries_cpuidle_devices, hotcpu); + + switch (action & 0xf) { + case CPU_ONLINE: + if (dev && cpuidle_get_driver()) { + cpuidle_disable_device(dev); + cpuidle_enable_device(dev); + } + break; } - return 0; + return NOTIFY_OK; }
+static struct notifier_block setup_hotplug_notifier = { + .notifier_call = pseries_cpuidle_add_cpu_notifier, +}; + /* * pseries_cpuidle_driver_init() */ @@ -321,6 +333,7 @@ static int __init pseries_processor_idle_init(void) return retval; }
+ register_cpu_notifier(&setup_hotplug_notifier); printk(KERN_DEBUG "pseries_idle_driver registered\n");
return 0; diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c index e16bb8d..71706bc 100644 --- a/arch/powerpc/platforms/pseries/smp.c +++ b/arch/powerpc/platforms/pseries/smp.c @@ -147,7 +147,6 @@ static void __devinit smp_xics_setup_cpu(int cpu) set_cpu_current_state(cpu, CPU_STATE_ONLINE); set_default_offline_state(cpu); #endif - pseries_notify_cpuidle_add_cpu(cpu); }
static int __devinit smp_pSeries_kick_cpu(int nr)
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