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    SubjectRe: [PATCH v2 06/13] sched: Store maximum per-cpu capacity in root domain
    On 22 June 2016 at 19:03, Morten Rasmussen <morten.rasmussen@arm.com> wrote:
    > From: Dietmar Eggemann <dietmar.eggemann@arm.com>
    >
    > To be able to compare the capacity of the target cpu with the highest
    > available cpu capacity, store the maximum per-cpu capacity in the root
    > domain.

    I thought that the capacity of all CPUS were built so the highest
    capacity of the CPU of the system is 1024 for big LITTLE system . So
    this patch doesn't seem necessary for big.LITTLE system

    >
    > cc: Ingo Molnar <mingo@redhat.com>
    > cc: Peter Zijlstra <peterz@infradead.org>
    >
    > Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
    > Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
    > ---
    > kernel/sched/core.c | 9 +++++++++
    > kernel/sched/sched.h | 2 ++
    > 2 files changed, 11 insertions(+)
    >
    > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
    > index fe39118ffdfb..5093765e9930 100644
    > --- a/kernel/sched/core.c
    > +++ b/kernel/sched/core.c
    > @@ -6855,6 +6855,7 @@ static int build_sched_domains(const struct cpumask *cpu_map,
    > enum s_alloc alloc_state;
    > struct sched_domain *sd;
    > struct s_data d;
    > + struct rq *rq = NULL;
    > int i, ret = -ENOMEM;
    >
    > alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
    > @@ -6905,11 +6906,19 @@ static int build_sched_domains(const struct cpumask *cpu_map,
    > /* Attach the domains */
    > rcu_read_lock();
    > for_each_cpu(i, cpu_map) {
    > + rq = cpu_rq(i);
    > sd = *per_cpu_ptr(d.sd, i);
    > cpu_attach_domain(sd, d.rd, i);
    > +
    > + if (rq->cpu_capacity_orig > rq->rd->max_cpu_capacity)
    > + rq->rd->max_cpu_capacity = rq->cpu_capacity_orig;
    > }
    > rcu_read_unlock();
    >
    > + if (rq)
    > + pr_info("span: %*pbl (max cpu_capacity = %lu)\n",
    > + cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity);
    > +
    > ret = 0;
    > error:
    > __free_domain_allocs(&d, alloc_state, cpu_map);
    > diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
    > index 72f1f3087b04..3e9904ef224f 100644
    > --- a/kernel/sched/sched.h
    > +++ b/kernel/sched/sched.h
    > @@ -564,6 +564,8 @@ struct root_domain {
    > */
    > cpumask_var_t rto_mask;
    > struct cpupri cpupri;
    > +
    > + unsigned long max_cpu_capacity;
    > };
    >
    > extern struct root_domain def_root_domain;
    > --
    > 1.9.1
    >

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