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powerpc/pseries/cpuidle: Replace pseries_notify_cpuidle_add call with notifier

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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>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This commit is contained in:
Deepthi Dharwar 2012-05-20 18:34:27 +00:00 committed by Benjamin Herrenschmidt
parent 25ebc45b93
commit 16aaaff684
3 changed files with 19 additions and 9 deletions
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2
arch/powerpc/include/asm/processor.h
View file

@ -389,10 +389,8 @@ extern int powersave_nap; /* set if nap mode can be used in idle loop */
#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);

25
arch/powerpc/platforms/pseries/processor_idle.c
View file

@ -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;

1
arch/powerpc/platforms/pseries/smp.c
View file

@ -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)