On Thursday, March 09, 2017 05:15:15 PM Viresh Kumar wrote:
From: Steve Muckle smuckle.linux@gmail.com
Upcoming support for remote callbacks from the scheduler into schedutil requires that the CPU identified in the hook structure be used to indicate the CPU being operated on, rather than relying on smp_processor_id().
Note that policy->cpu is passed to trace_cpu_frequency() in fast switch path, as it is safe to use any CPU which is managed by the current policy.
This should be commented about in the code too IMO.
Signed-off-by: Steve Muckle smuckle.linux@gmail.com [ vk: updated commit log, minor code cleanups and use policy->cpu for traces ] Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
kernel/sched/cpufreq_schedutil.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index a418544c51b1..b168c31f1c8f 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -96,7 +96,7 @@ static void sugov_fast_switch(struct cpufreq_policy *policy, return; policy->cur = next_freq;
- trace_cpu_frequency(next_freq, smp_processor_id());
- trace_cpu_frequency(next_freq, policy->cpu);
} static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time, @@ -106,7 +106,7 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time, if (policy->fast_switch_enabled) { if (sg_policy->next_freq == next_freq) {
trace_cpu_frequency(policy->cur, smp_processor_id());
trace_cpu_frequency(policy->cur, policy->cpu); return;@@ -157,12 +157,12 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy, return cpufreq_driver_resolve_freq(policy, freq); } -static void sugov_get_util(unsigned long *util, unsigned long *max) +static void sugov_get_util(unsigned long *util, unsigned long *max, int cpu) {
- struct rq *rq = this_rq();
- struct rq *rq = cpu_rq(cpu); unsigned long cfs_max;
- cfs_max = arch_scale_cpu_capacity(NULL, smp_processor_id());
- cfs_max = arch_scale_cpu_capacity(NULL, cpu);
*util = min(rq->cfs.avg.util_avg, cfs_max); *max = cfs_max; @@ -216,7 +216,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, if (flags & SCHED_CPUFREQ_RT_DL) { next_f = policy->cpuinfo.max_freq; } else {
sugov_get_util(&util, &max);
sugov_get_util(&util, &max, hook->cpu);
Why is this not racy?
sugov_iowait_boost(sg_cpu, &util, &max); next_f = get_next_freq(sg_policy, util, max);} @@ -272,7 +272,7 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time, unsigned long util, max; unsigned int next_f;
- sugov_get_util(&util, &max);
- sugov_get_util(&util, &max, hook->cpu);
And here?
raw_spin_lock(&sg_policy->update_lock);
Thanks, Rafael