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 eb70592f03f624fca69b2d0317f4a0cf1d52e940..879bdffc928be26024e5e9b079c7178bc501789e 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;