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    SubjectRe: [RFCv5 PATCH 45/46] sched/cpufreq_sched: modify pcpu_capacity handling
    Hi Peter,

    On 16/08/15 21:35, Peter Zijlstra wrote:
    > On Tue, Jul 07, 2015 at 07:24:28PM +0100, Morten Rasmussen wrote:
    >> From: Juri Lelli <juri.lelli@arm.com>
    >>
    >> Use the cpu argument of cpufreq_sched_set_cap() to handle per_cpu writes,
    >> as the thing can be called remotely (e.g., from load balacing code).
    >>
    >> cc: Ingo Molnar <mingo@redhat.com>
    >> cc: Peter Zijlstra <peterz@infradead.org>
    >>
    >> Signed-off-by: Juri Lelli <juri.lelli@arm.com>
    >> ---
    >> kernel/sched/cpufreq_sched.c | 2 +-
    >> 1 file changed, 1 insertion(+), 1 deletion(-)
    >>
    >> diff --git a/kernel/sched/cpufreq_sched.c b/kernel/sched/cpufreq_sched.c
    >> index 06ff183..b81ac779 100644
    >> --- a/kernel/sched/cpufreq_sched.c
    >> +++ b/kernel/sched/cpufreq_sched.c
    >> @@ -151,7 +151,7 @@ void cpufreq_sched_set_cap(int cpu, unsigned long capacity)
    >> unsigned long capacity_max = 0;
    >>
    >> /* update per-cpu capacity request */
    >> - __this_cpu_write(pcpu_capacity, capacity);
    >> + per_cpu(pcpu_capacity, cpu) = capacity;
    >>
    >> policy = cpufreq_cpu_get(cpu);
    >> if (IS_ERR_OR_NULL(policy)) {
    >
    > Uhm,.. this function seems to hard assume its called for the local CPU.
    > It will only use the irq_queue_work_on() if the cpufreq thing requires
    > the thread, otherwise it will call the method directly on the calling
    > cpu.
    >

    True, but we still retrieve policy from cpu passed as argument; and
    then we use policy to request a freq transition, that should end up
    updating the right cpu.

    Thanks,

    - Juri



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