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Commit 3fa8cad8 authored by Deepthi Dharwar's avatar Deepthi Dharwar Committed by Benjamin Herrenschmidt
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powerpc/pseries/cpuidle: smt-snooze-delay cleanup. 



smt-snooze-delay was designed to disable NAP state or delay the entry
to the NAP state prior to adoption of cpuidle framework. This
is per-cpu variable. With the coming of CPUIDLE framework,
states can be disabled on per-cpu basis using the cpuidle/enable
sysfs entry.

Also, with the coming of cpuidle driver each state's target residency
is per-driver unlike earlier which was per-device. Therefore,
the per-cpu sysfs smt-snooze-delay which decides the target residency
of the idle state on a particular cpu causes more confusion to the user
as we cannot have different smt-snooze-delay (target residency)
values for each cpu.

In the current code, smt-snooze-delay functionality is completely broken.
It makes sense to remove smt-snooze-delay from idle driver with the
coming of cpuidle framework.
However, sysfs files are retained as ppc64_util currently
utilises it. Once we fix ppc64_util, propose to clean
up the kernel code.

Signed-off-by: default avatarDeepthi Dharwar <deepthi@linux.vnet.ibm.com>
Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
parent bf7f61f2

arch/powerpc/include/asm/processor.h

+0 −7
Original line number Diff line number Diff line
@@ -450,13 +450,6 @@ enum idle_boot_override {IDLE_NO_OVERRIDE = 0, IDLE_POWERSAVE_OFF}; 


extern int powersave_nap;	/* set if nap mode can be used in idle loop */

extern void power7_nap(void);



#ifdef CONFIG_PSERIES_CPUIDLE

extern void update_smt_snooze_delay(int cpu, int residency);

#else

static inline void update_smt_snooze_delay(int cpu, int residency) {}

#endif



extern void flush_instruction_cache(void);

extern void hard_reset_now(void);

extern void poweroff_now(void);

arch/powerpc/kernel/sysfs.c

+0 −2
Original line number Diff line number Diff line
@@ -51,8 +51,6 @@ static ssize_t store_smt_snooze_delay(struct device *dev, 
		return -EINVAL;



	per_cpu(smt_snooze_delay, cpu->dev.id) = snooze;

	update_smt_snooze_delay(cpu->dev.id, snooze);



	return count;

}

drivers/cpuidle/cpuidle-pseries.c

+0 −17
Original line number Diff line number Diff line
@@ -162,23 +162,6 @@ static struct cpuidle_state shared_states[] = { 
		.enter = &shared_cede_loop },

};



void update_smt_snooze_delay(int cpu, int residency)

{

	struct cpuidle_driver *drv = cpuidle_get_driver();

	struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);



	if (cpuidle_state_table != dedicated_states)

		return;



	if (residency < 0) {

		/* Disable the Nap state on that cpu */

		if (dev)

			dev->states_usage[1].disable = 1;

	} else

		if (drv)

			drv->states[1].target_residency = residency;

}



static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n,

			unsigned long action, void *hcpu)

{