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Commit c74f31c0 authored by Mike Travis's avatar Mike Travis Committed by Ingo Molnar
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cpumask: use work_on_cpu in acpi/cstate.c 



Impact: use new cpumask API to reduce stack usage

Replace the saving of current->cpus_allowed and set_cpus_allowed_ptr() with
a work_on_cpu function for the acpi_processor_ffh_cstate_probe() function.

Basically splits acpi_processor_ffh_cstate_probe() into two functions, the
other being acpi_processor_ffh_cstate_probe_cpu which is the work function
run on the designated cpu.

Signed-off-by: default avatarMike Travis <travis@sgi.com>
Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 835481d9

arch/x86/kernel/acpi/cstate.c

+37 −33
Original line number Diff line number Diff line
@@ -66,35 +66,15 @@ static short mwait_supported[ACPI_PROCESSOR_MAX_POWER]; 


#define NATIVE_CSTATE_BEYOND_HALT	(2)



int acpi_processor_ffh_cstate_probe(unsigned int cpu,

		struct acpi_processor_cx *cx, struct acpi_power_register *reg)

static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)

{

	struct cstate_entry *percpu_entry;

	struct cpuinfo_x86 *c = &cpu_data(cpu);



	cpumask_t saved_mask;

	int retval;

	struct acpi_processor_cx *cx = _cx;

	long retval;

	unsigned int eax, ebx, ecx, edx;

	unsigned int edx_part;

	unsigned int cstate_type; /* C-state type and not ACPI C-state type */

	unsigned int num_cstate_subtype;



	if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF )

		return -1;



	if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)

		return -1;



	percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);

	percpu_entry->states[cx->index].eax = 0;

	percpu_entry->states[cx->index].ecx = 0;



	/* Make sure we are running on right CPU */

	saved_mask = current->cpus_allowed;

	retval = set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));

	if (retval)

		return -1;



	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);



	/* Check whether this particular cx_type (in CST) is supported or not */
@@ -114,21 +94,45 @@ int acpi_processor_ffh_cstate_probe(unsigned int cpu, 
		retval = -1;

		goto out;

	}

	percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;



	/* Use the hint in CST */

	percpu_entry->states[cx->index].eax = cx->address;



	if (!mwait_supported[cstate_type]) {

		mwait_supported[cstate_type] = 1;

		printk(KERN_DEBUG "Monitor-Mwait will be used to enter C-%d "

		printk(KERN_DEBUG

			"Monitor-Mwait will be used to enter C-%d "

			"state\n", cx->type);

	}

	snprintf(cx->desc, ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",

	snprintf(cx->desc,

			ACPI_CX_DESC_LEN, "ACPI FFH INTEL MWAIT 0x%x",

			cx->address);



out:

	set_cpus_allowed_ptr(current, &saved_mask);

	return retval;

}



int acpi_processor_ffh_cstate_probe(unsigned int cpu,

		struct acpi_processor_cx *cx, struct acpi_power_register *reg)

{

	struct cstate_entry *percpu_entry;

	struct cpuinfo_x86 *c = &cpu_data(cpu);

	long retval;



	if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF)

		return -1;



	if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)

		return -1;



	percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);

	percpu_entry->states[cx->index].eax = 0;

	percpu_entry->states[cx->index].ecx = 0;



	/* Make sure we are running on right CPU */



	retval = work_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx);

	if (retval == 0) {

		/* Use the hint in CST */

		percpu_entry->states[cx->index].eax = cx->address;

		percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;

	}

	return retval;

}

EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);