| Message ID | 20171102105438.14258-1-chris.redpath@arm.com |
|---|---|
| State | Accepted |
| Commit | d62d813c0d714a2d0aaf3d796a7a51ae60bf5470 |
| Headers | show |
| Series | cpufreq: schedutil: Examine the correct CPU when we update util | expand |
On 02-11-17, 10:54, Chris Redpath wrote: > Since: > > 4296f23ed cpufreq: schedutil: Fix per-CPU structure initialization in > sugov_start() Good catch but you pointed out to the wrong commit really. 674e75411fc2 ("sched: cpufreq: Allow remote cpufreq callbacks" is the real culprit as that's where the 'cpu' field is added. > We lost the value of sg_cpu->cpu which is assigned during > sugov_register. The memset in sugov_start overwrites it with zero. > > This leads to always looking at the utilization of CPU0 instead of > the one we just updated when we do a utilization update callback. > > Let's fix this by consolidating the initialization code into > sugov_start(). > > Fixes: 4296f23ed49a ("cpufreq: schedutil: Fix per-CPU structure initialization in sugov_start()") Fixes: 674e75411fc2 ("sched: cpufreq: Allow remote cpufreq callbacks") > Signed-off-by: Chris Redpath <chris.redpath@arm.com> > Reviewed-by: Patrick Bellasi <patrick.bellasi@arm.com> > Reviewed-by: Brendan Jackman <brendan.jackman@arm.com> > Cc: Rafael J. Wysocki <rjw@rjwysocki.net> > Cc: Viresh Kumar <viresh.kumar@linaro.org> > Cc: Ingo Molnar <mingo@redhat.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: 4.9+ <stable@vger.kernel.org> This wouldn't be required now as it got merged in 4.14 only and Rafael should be able to get that as part of 4.14 itself. > --- > kernel/sched/cpufreq_schedutil.c | 6 +----- > 1 file changed, 1 insertion(+), 5 deletions(-) > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index 6c1a7fcfa2a7..eeb7e0a1d861 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -731,6 +731,7 @@ static int sugov_start(struct cpufreq_policy *policy) > sg_cpu->sg_policy = sg_policy; > sg_cpu->flags = SCHED_CPUFREQ_RT; > sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq; > + sg_cpu->cpu = cpu; Maybe just move this below memset. > } > > for_each_cpu(cpu, policy->cpus) { > @@ -793,11 +794,6 @@ struct cpufreq_governor *cpufreq_default_governor(void) > > static int __init sugov_register(void) > { > - int cpu; > - > - for_each_possible_cpu(cpu) > - per_cpu(sugov_cpu, cpu).cpu = cpu; > - > return cpufreq_register_governor(&schedutil_gov); > } > fs_initcall(sugov_register); Diff looks fine though. -- viresh
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 6c1a7fcfa2a7..eeb7e0a1d861 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -731,6 +731,7 @@ static int sugov_start(struct cpufreq_policy *policy) sg_cpu->sg_policy = sg_policy; sg_cpu->flags = SCHED_CPUFREQ_RT; sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq; + sg_cpu->cpu = cpu; } for_each_cpu(cpu, policy->cpus) { @@ -793,11 +794,6 @@ struct cpufreq_governor *cpufreq_default_governor(void) static int __init sugov_register(void) { - int cpu; - - for_each_possible_cpu(cpu) - per_cpu(sugov_cpu, cpu).cpu = cpu; - return cpufreq_register_governor(&schedutil_gov); } fs_initcall(sugov_register);
Since: 4296f23ed cpufreq: schedutil: Fix per-CPU structure initialization in sugov_start() We lost the value of sg_cpu->cpu which is assigned during sugov_register. The memset in sugov_start overwrites it with zero. This leads to always looking at the utilization of CPU0 instead of the one we just updated when we do a utilization update callback. Let's fix this by consolidating the initialization code into sugov_start(). Fixes: 4296f23ed49a ("cpufreq: schedutil: Fix per-CPU structure initialization in sugov_start()") Signed-off-by: Chris Redpath <chris.redpath@arm.com> Reviewed-by: Patrick Bellasi <patrick.bellasi@arm.com> Reviewed-by: Brendan Jackman <brendan.jackman@arm.com> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: 4.9+ <stable@vger.kernel.org> --- kernel/sched/cpufreq_schedutil.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) -- 2.13.1.449.g02a2850