sched: Store system-wide maximum cpu capacity in root domain

To be able to compare the capacity of the target cpu with the highest
cpu capacity of the system in the wakeup path, store the system-wide
maximum cpu capacity in the root domain.

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 732e993b564b8179e5723bb88839329eec6df8f5..7c6e2b3263490f57d58ac30556c11630a9bc3744 100644 (file)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6971,6 +6971,7 @@ 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);
@@ -7021,11 +7022,18 @@ 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("max cpu_capacity %lu\n", 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 b242775bf670e116233862c590915e06132485ca..2b7ffa5a20ad4836efa2ecb812fb05f50f1355d3 100644 (file)
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -543,6 +543,9 @@ struct root_domain {
         */
        cpumask_var_t rto_mask;
        struct cpupri cpupri;
+
+       /* Maximum cpu capacity in the system. */
+       unsigned long max_cpu_capacity;
 };
 
 extern struct root_domain def_root_domain;