On Wednesday, August 12, 2015 11:49:19 AM Chen Yu wrote: > In current code, if system is using performance policy, user can > modify the max_perf_pct to any values lower than 100: > > $ grep . /sys/devices/system/cpu/intel_pstate/m*_perf_pct > /sys/devices/system/cpu/intel_pstate/max_perf_pct:100 > /sys/devices/system/cpu/intel_pstate/min_perf_pct:100 > > $ echo 80 > /sys/devices/system/cpu/intel_pstate/max_perf_pct > > $ grep . /sys/devices/system/cpu/intel_pstate/m*_perf_pct > /sys/devices/system/cpu/intel_pstate/max_perf_pct:80 > /sys/devices/system/cpu/intel_pstate/min_perf_pct:100 > > the max_perf_pct above is lower than min_perf_pct, which > is not reasonable. > > This patch solves this problem by clamping min_perf_pct and max_perf_pct > to be strictly inside [min_policy_pct,max_policy_pct]. > > Signed-off-by: Chen Yu <yu.c.c...@intel.com>
Looks reasonable to me. Kristen, any objections? > --- > drivers/cpufreq/intel_pstate.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index fcb929e..3702c5a 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -423,6 +423,7 @@ static ssize_t store_max_perf_pct(struct kobject *a, > struct attribute *b, > > limits.max_sysfs_pct = clamp_t(int, input, 0 , 100); > limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct); > + limits.max_perf_pct = max(limits.min_policy_pct, limits.max_perf_pct); > limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100)); > > if (hwp_active) > @@ -442,6 +443,7 @@ static ssize_t store_min_perf_pct(struct kobject *a, > struct attribute *b, > > limits.min_sysfs_pct = clamp_t(int, input, 0 , 100); > limits.min_perf_pct = max(limits.min_policy_pct, limits.min_sysfs_pct); > + limits.min_perf_pct = min(limits.max_policy_pct, limits.min_perf_pct); > limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); > > if (hwp_active) > @@ -985,12 +987,14 @@ static int intel_pstate_set_policy(struct > cpufreq_policy *policy) > > limits.min_policy_pct = (policy->min * 100) / policy->cpuinfo.max_freq; > limits.min_policy_pct = clamp_t(int, limits.min_policy_pct, 0 , 100); > - limits.min_perf_pct = max(limits.min_policy_pct, limits.min_sysfs_pct); > - limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); > - > limits.max_policy_pct = (policy->max * 100) / policy->cpuinfo.max_freq; > limits.max_policy_pct = clamp_t(int, limits.max_policy_pct, 0 , 100); > + > + limits.min_perf_pct = max(limits.min_policy_pct, limits.min_sysfs_pct); > + limits.min_perf_pct = min(limits.max_policy_pct, limits.min_perf_pct); > + limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); > limits.max_perf_pct = min(limits.max_policy_pct, limits.max_sysfs_pct); > + limits.max_perf_pct = max(limits.min_policy_pct, limits.max_perf_pct); > limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100)); > > if (hwp_active) > -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
