On Wed, 9 Sep 2015 18:27:31 +0800 Chen Yu <yu.c.c...@intel.com> wrote:
> In current code, max_perf_pct might be smaller than min_perf_pct > by improper user input: > > $ 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 > > Fix this problem by 2 steps: > 1.Normalize the user input to [min_policy, max_policy]. > 2.Make sure max_perf_pct>=min_perf_pct, suggested by Seiichi Ikarashi. > > Signed-off-by: Chen Yu <yu.c.c...@intel.com> Acked-by: Kristen Carlson Accardi <kris...@linux.intel.com> > --- > v2: > - Add logic to ensure max_perf_pct>=min_perf_pct. > --- > drivers/cpufreq/intel_pstate.c | 17 ++++++++++++++--- > 1 file changed, 14 insertions(+), 3 deletions(-) > > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c > index fcb929e..a0b935f 100644 > --- a/drivers/cpufreq/intel_pstate.c > +++ b/drivers/cpufreq/intel_pstate.c > @@ -423,6 +423,8 @@ 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_pct = max(limits.min_perf_pct, limits.max_perf_pct); > limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100)); > > if (hwp_active) > @@ -442,6 +444,8 @@ 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_pct = min(limits.max_perf_pct, limits.min_perf_pct); > limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); > > if (hwp_active) > @@ -985,12 +989,19 @@ 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); > + > + /* Normalize user input to [min_policy_pct, max_policy_pct] */ > + 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.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); > + > + /* Make sure min_perf_pct <= max_perf_pct */ > + limits.min_perf_pct = min(limits.max_perf_pct, limits.min_perf_pct); > + > + limits.min_perf = div_fp(int_tofp(limits.min_perf_pct), int_tofp(100)); > limits.max_perf = div_fp(int_tofp(limits.max_perf_pct), int_tofp(100)); > > if (hwp_active) -- 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/
