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cpumask: use work_on_cpu in acpi-cpufreq.c for read_measured_perf_ctrs

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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: Mike Travis <travis@sgi.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Mike Travis 2009-01-04 05:18:10 -08:00 committed by Ingo Molnar
parent 7503bfbae8
commit e39ad415ac
1 changed files with 43 additions and 40 deletions
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83
arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
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@ -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.