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: Mike Travis <travis@sgi.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
index 4e4f2b0..06fcd8f 100644
--- a/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
+++ b/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c
@@ -245,6 +245,30 @@
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 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 @@
* 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 @@
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 @@
}
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.