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Commit e39ad415 authored by Mike Travis's avatar Mike Travis Committed by Ingo Molnar
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cpumask: use work_on_cpu in acpi-cpufreq.c for read_measured_perf_ctrs 



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 read_measured_perf_ctrs().

Basically splits off the work function from get_measured_perf which is
run on the designated cpu.  Moves definition of struct perf_cur out of
function local namespace, and is used as the work function argument.
References in get_measured_perf use values in the perf_cur struct.

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 7503bfba

arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c

+43 −40
Original line number Diff line number Diff line
@@ -245,6 +245,30 @@ static u32 get_cur_val(const struct cpumask *mask) 
	return cmd.val;

}



struct perf_cur {

	union {

		struct {

			u32 lo;

			u32 hi;

		} split;

		u64 whole;

	} aperf_cur, mperf_cur;

};





static long read_measured_perf_ctrs(void *_cur)

{

	struct perf_cur *cur = _cur;



	rdmsr(MSR_IA32_APERF, cur->aperf_cur.split.lo, cur->aperf_cur.split.hi);

	rdmsr(MSR_IA32_MPERF, cur->mperf_cur.split.lo, cur->mperf_cur.split.hi);



	wrmsr(MSR_IA32_APERF, 0, 0);

	wrmsr(MSR_IA32_MPERF, 0, 0);



	return 0;

}



/*

 * Return the measured active (C0) frequency on this CPU since last call

 * to this function.
@@ -261,31 +285,12 @@ static u32 get_cur_val(const struct cpumask *mask) 
static unsigned int get_measured_perf(struct cpufreq_policy *policy,

				      unsigned int cpu)

{

	union {

		struct {

			u32 lo;

			u32 hi;

		} split;

		u64 whole;

	} aperf_cur, mperf_cur;



	cpumask_t saved_mask;

	struct perf_cur cur;

	unsigned int perf_percent;

	unsigned int retval;



	saved_mask = current->cpus_allowed;

	set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));

	if (get_cpu() != cpu) {

		/* We were not able to run on requested processor */

		put_cpu();

	if (!work_on_cpu(cpu, read_measured_perf_ctrs, &cur))

		return 0;

	}



	rdmsr(MSR_IA32_APERF, aperf_cur.split.lo, aperf_cur.split.hi);

	rdmsr(MSR_IA32_MPERF, mperf_cur.split.lo, mperf_cur.split.hi);



	wrmsr(MSR_IA32_APERF, 0,0);

	wrmsr(MSR_IA32_MPERF, 0,0);



#ifdef __i386__

	/*
@@ -293,37 +298,39 @@ static unsigned int get_measured_perf(struct cpufreq_policy *policy, 
	 * Get an approximate value. Return failure in case we cannot get

	 * an approximate value.

	 */

	if (unlikely(aperf_cur.split.hi || mperf_cur.split.hi)) {

	if (unlikely(cur.aperf_cur.split.hi || cur.mperf_cur.split.hi)) {

		int shift_count;

		u32 h;



		h = max_t(u32, aperf_cur.split.hi, mperf_cur.split.hi);

		h = max_t(u32, cur.aperf_cur.split.hi, cur.mperf_cur.split.hi);

		shift_count = fls(h);



		aperf_cur.whole >>= shift_count;

		mperf_cur.whole >>= shift_count;

		cur.aperf_cur.whole >>= shift_count;

		cur.mperf_cur.whole >>= shift_count;

	}



	if (((unsigned long)(-1) / 100) < aperf_cur.split.lo) {

	if (((unsigned long)(-1) / 100) < cur.aperf_cur.split.lo) {

		int shift_count = 7;

		aperf_cur.split.lo >>= shift_count;

		mperf_cur.split.lo >>= shift_count;

		cur.aperf_cur.split.lo >>= shift_count;

		cur.mperf_cur.split.lo >>= shift_count;

	}



	if (aperf_cur.split.lo && mperf_cur.split.lo)

		perf_percent = (aperf_cur.split.lo * 100) / mperf_cur.split.lo;

	if (cur.aperf_cur.split.lo && cur.mperf_cur.split.lo)

		perf_percent = (cur.aperf_cur.split.lo * 100) /

				cur.mperf_cur.split.lo;

	else

		perf_percent = 0;



#else

	if (unlikely(((unsigned long)(-1) / 100) < aperf_cur.whole)) {

	if (unlikely(((unsigned long)(-1) / 100) < cur.aperf_cur.whole)) {

		int shift_count = 7;

		aperf_cur.whole >>= shift_count;

		mperf_cur.whole >>= shift_count;

		cur.aperf_cur.whole >>= shift_count;

		cur.mperf_cur.whole >>= shift_count;

	}



	if (aperf_cur.whole && mperf_cur.whole)

		perf_percent = (aperf_cur.whole * 100) / mperf_cur.whole;

	if (cur.aperf_cur.whole && cur.mperf_cur.whole)

		perf_percent = (cur.aperf_cur.whole * 100) /

				cur.mperf_cur.whole;

	else

		perf_percent = 0;
@@ -331,10 +338,6 @@ static unsigned int get_measured_perf(struct cpufreq_policy *policy, 


	retval = per_cpu(drv_data, policy->cpu)->max_freq * perf_percent / 100;



	put_cpu();

	set_cpus_allowed_ptr(current, &saved_mask);



	dprintk("cpu %d: performance percent %d\n", cpu, perf_percent);

	return retval;

}
@@ -352,7 +355,7 @@ static unsigned int get_cur_freq_on_cpu(unsigned int cpu) 
	}



	cached_freq = data->freq_table[data->acpi_data->state].frequency;

	freq = extract_freq(get_cur_val(&cpumask_of_cpu(cpu)), data);

	freq = extract_freq(get_cur_val(cpumask_of(cpu)), data);

	if (freq != cached_freq) {

		/*

		 * The dreaded BIOS frequency change behind our back.