Commit 16aaaff6 authored by Deepthi Dharwar's avatar Deepthi Dharwar Committed by Benjamin Herrenschmidt

powerpc/pseries/cpuidle: Replace pseries_notify_cpuidle_add call with notifier

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: default avatarDeepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent 25ebc45b
...@@ -389,10 +389,8 @@ extern int powersave_nap; /* set if nap mode can be used in idle loop */ ...@@ -389,10 +389,8 @@ extern int powersave_nap; /* set if nap mode can be used in idle loop */
#ifdef CONFIG_PSERIES_IDLE #ifdef CONFIG_PSERIES_IDLE
extern void update_smt_snooze_delay(int snooze); extern void update_smt_snooze_delay(int snooze);
extern int pseries_notify_cpuidle_add_cpu(int cpu);
#else #else
static inline void update_smt_snooze_delay(int snooze) {} static inline void update_smt_snooze_delay(int snooze) {}
static inline int pseries_notify_cpuidle_add_cpu(int cpu) { return 0; }
#endif #endif
extern void flush_instruction_cache(void); extern void flush_instruction_cache(void);
......
...@@ -11,6 +11,7 @@ ...@@ -11,6 +11,7 @@
#include <linux/moduleparam.h> #include <linux/moduleparam.h>
#include <linux/cpuidle.h> #include <linux/cpuidle.h>
#include <linux/cpu.h> #include <linux/cpu.h>
#include <linux/notifier.h>
#include <asm/paca.h> #include <asm/paca.h>
#include <asm/reg.h> #include <asm/reg.h>
...@@ -186,17 +187,28 @@ static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { ...@@ -186,17 +187,28 @@ static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = {
.enter = &shared_cede_loop }, .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 = struct cpuidle_device *dev =
per_cpu_ptr(pseries_cpuidle_devices, cpu); per_cpu_ptr(pseries_cpuidle_devices, hotcpu);
if (dev && cpuidle_get_driver()) {
cpuidle_disable_device(dev); switch (action & 0xf) {
cpuidle_enable_device(dev); 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() * pseries_cpuidle_driver_init()
*/ */
...@@ -321,6 +333,7 @@ static int __init pseries_processor_idle_init(void) ...@@ -321,6 +333,7 @@ static int __init pseries_processor_idle_init(void)
return retval; return retval;
} }
register_cpu_notifier(&setup_hotplug_notifier);
printk(KERN_DEBUG "pseries_idle_driver registered\n"); printk(KERN_DEBUG "pseries_idle_driver registered\n");
return 0; return 0;
......
...@@ -147,7 +147,6 @@ static void __devinit smp_xics_setup_cpu(int cpu) ...@@ -147,7 +147,6 @@ static void __devinit smp_xics_setup_cpu(int cpu)
set_cpu_current_state(cpu, CPU_STATE_ONLINE); set_cpu_current_state(cpu, CPU_STATE_ONLINE);
set_default_offline_state(cpu); set_default_offline_state(cpu);
#endif #endif
pseries_notify_cpuidle_add_cpu(cpu);
} }
static int __devinit smp_pSeries_kick_cpu(int nr) static int __devinit smp_pSeries_kick_cpu(int nr)
......
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