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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-08-17 14:21:18 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-08-17 14:21:18 -0700 |
| commit | d33a2a914319e9ec71f49bad2b8c8b9e05a58edf (patch) | |
| tree | 4e4de33d81a96e99da477ed28e3eb5965be475d2 /arch/x86 | |
| parent | 440105d3c958cf10b5900fac9d4632d47d57a0cc (diff) | |
| parent | 8179962b84668d71586cd3efcb70e823f37a5702 (diff) | |
Merge tag 'pm-4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix two issues related to exposing the current CPU frequency to
user space on x86.
Specifics:
- Disable interrupts around reading IA32_APERF and IA32_MPERF in
aperfmperf_snapshot_khz() (introduced recently) to avoid excessive
delays between the reads that may result from interrupt handling
(Doug Smythies).
- Fix the computation of the CPU frequency to be reported through the
pstate_sample tracepoint in intel_pstate (Doug Smythies)"
* tag 'pm-4.13-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: x86: Disable interrupts during MSRs reading
cpufreq: intel_pstate: report correct CPU frequencies during trace
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/cpu/aperfmperf.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c index 7cf7c70b6ef2..0ee83321a313 100644 --- a/arch/x86/kernel/cpu/aperfmperf.c +++ b/arch/x86/kernel/cpu/aperfmperf.c @@ -40,13 +40,16 @@ static void aperfmperf_snapshot_khz(void *dummy) struct aperfmperf_sample *s = this_cpu_ptr(&samples); ktime_t now = ktime_get(); s64 time_delta = ktime_ms_delta(now, s->time); + unsigned long flags; /* Don't bother re-computing within the cache threshold time. */ if (time_delta < APERFMPERF_CACHE_THRESHOLD_MS) return; + local_irq_save(flags); rdmsrl(MSR_IA32_APERF, aperf); rdmsrl(MSR_IA32_MPERF, mperf); + local_irq_restore(flags); aperf_delta = aperf - s->aperf; mperf_delta = mperf - s->mperf; |