Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

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

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

arch/powerpc/include/asm/processor.h

+0 −2
Original line number Diff line number Diff line
@@ -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);

arch/powerpc/platforms/pseries/processor_idle.c

+19 −6
Original line number Diff line number Diff line
@@ -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>
@@ -186,16 +187,27 @@ 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);

			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);

		}

	return 0;

		break;

	}

	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;

arch/powerpc/platforms/pseries/smp.c

+0 −1
Original line number Diff line number Diff line
@@ -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)