On 02-11-17, 11:38, Chris Redpath wrote:
> Since:
> 4296f23ed cpufreq: schedutil: Fix per-CPU structure initialization in
> sugov_start()
This is still incorrect. This BUG has nothing to do with 4296f23ed
AFAICT.
> We lost the value of sg_cpu->cpu which is assigned during
> sugov_register. The memset in sugov_start overwrites it with zero.
>
> The change here was triggered by the commit adding the remote update
> functionality.
> 674e75411fc2 ("sched: cpufreq: Allow remote cpufreq callbacks")
>
> 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: 674e75411fc2 ("sched: cpufreq: Allow remote cpufreq callbacks")
> Signed-off-by: Chris Redpath <chris.redp...@arm.com>
> Reviewed-by: Patrick Bellasi <patrick.bell...@arm.com>
> Reviewed-by: Brendan Jackman <brendan.jack...@arm.com>
> Cc: Rafael J. Wysocki <r...@rjwysocki.net>
> Cc: Viresh Kumar <viresh.ku...@linaro.org>
> Cc: Ingo Molnar <mi...@redhat.com>
> Cc: Peter Zijlstra <pet...@infradead.org>
> ---
> 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..dc68a1ccdb33 100644
> --- a/kernel/sched/cpufreq_schedutil.c
> +++ b/kernel/sched/cpufreq_schedutil.c
> @@ -728,6 +728,7 @@ static int sugov_start(struct cpufreq_policy *policy)
> struct sugov_cpu *sg_cpu = &per_cpu(sugov_cpu, cpu);
>
> memset(sg_cpu, 0, sizeof(*sg_cpu));
> + sg_cpu->cpu = cpu;
> sg_cpu->sg_policy = sg_policy;
> sg_cpu->flags = SCHED_CPUFREQ_RT;
> sg_cpu->iowait_boost_max = policy->cpuinfo.max_freq;
> @@ -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);
> --
> 2.13.1.449.g02a2850
--
viresh
