| Message ID | 5898530.IS6IniWbqq@aspire.rjw.lan (mailing list archive) |
|---|---|
| State | Mainlined |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On 26-07-17, 00:42, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > > The ->get callback in the intel_pstate structure was mostly there > for the scaling_cur_freq sysfs attribute to work, but after commit > f8475cef9008 (x86: use common aperfmperf_khz_on_cpu() to calculate > KHz using APERF/MPERF) that attribute uses arch_freq_get_on_cpu() > provided by the x86 arch code on all processors supported by > intel_pstate, so it doesn't need the ->get callback from the > driver any more. > > Moreover, the very presence of the ->get callback in the intel_pstate > structure causes the cpuinfo_cur_freq attribute to be present when > intel_pstate operates in the active mode, which is bogus, because > the role of that attribute is to return the current CPU frequency > as seen by the hardware. For intel_pstate, though, this is just an > average frequency and not really current, but computed for the > previous sampling interval (the actual current frequency may be > way different at the point this value is obtained by reading from > cpuinfo_cur_freq), and after commit 82b4e03e01bc (intel_pstate: skip > scheduler hook when in "performance" mode) the value in > cpuinfo_cur_freq may be stale or just 0, depending on the driver's > operation mode. In fact, however, on the hardware supported by > intel_pstate there is no way to read the current CPU frequency > from it, so the cpuinfo_cur_freq attribute should not be present > at all when this driver is in use. > > For this reason, drop intel_pstate_get() and clear the ->get > callback pointer pointing to it, so that the cpuinfo_cur_freq is > not present for intel_pstate in the active mode any more. > > Fixes: 82b4e03e01bc (intel_pstate: skip scheduler hook when in "performance" mode) > Reported-by: Huaisheng Ye <yehs1@lenovo.com> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > --- > drivers/cpufreq/intel_pstate.c | 8 -------- > 1 file changed, 8 deletions(-) > > Index: linux-pm/drivers/cpufreq/intel_pstate.c > =================================================================== > --- linux-pm.orig/drivers/cpufreq/intel_pstate.c > +++ linux-pm/drivers/cpufreq/intel_pstate.c > @@ -1674,13 +1674,6 @@ static int intel_pstate_init_cpu(unsigne > return 0; > } > > -static unsigned int intel_pstate_get(unsigned int cpu_num) > -{ > - struct cpudata *cpu = all_cpu_data[cpu_num]; > - > - return cpu ? get_avg_frequency(cpu) : 0; > -} > - > static void intel_pstate_set_update_util_hook(unsigned int cpu_num) > { > struct cpudata *cpu = all_cpu_data[cpu_num]; > @@ -1921,7 +1914,6 @@ static struct cpufreq_driver intel_pstat > .setpolicy = intel_pstate_set_policy, > .suspend = intel_pstate_hwp_save_state, > .resume = intel_pstate_resume, > - .get = intel_pstate_get, > .init = intel_pstate_cpu_init, > .exit = intel_pstate_cpu_exit, > .stop_cpu = intel_pstate_stop_cpu, Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Index: linux-pm/drivers/cpufreq/intel_pstate.c =================================================================== --- linux-pm.orig/drivers/cpufreq/intel_pstate.c +++ linux-pm/drivers/cpufreq/intel_pstate.c @@ -1674,13 +1674,6 @@ static int intel_pstate_init_cpu(unsigne return 0; } -static unsigned int intel_pstate_get(unsigned int cpu_num) -{ - struct cpudata *cpu = all_cpu_data[cpu_num]; - - return cpu ? get_avg_frequency(cpu) : 0; -} - static void intel_pstate_set_update_util_hook(unsigned int cpu_num) { struct cpudata *cpu = all_cpu_data[cpu_num]; @@ -1921,7 +1914,6 @@ static struct cpufreq_driver intel_pstat .setpolicy = intel_pstate_set_policy, .suspend = intel_pstate_hwp_save_state, .resume = intel_pstate_resume, - .get = intel_pstate_get, .init = intel_pstate_cpu_init, .exit = intel_pstate_cpu_exit, .stop_cpu = intel_pstate_stop_cpu,