[PATCH 08/16] sched: Store maximum per-cpu capacity in root domain

[Morten Rasmussen]

From: Dietmar Eggemann <dietmar.eggem...@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.

cc: Ingo Molnar <mi...@redhat.com>
cc: Peter Zijlstra <pet...@infradead.org>

Signed-off-by: Dietmar Eggemann <dietmar.eggem...@arm.com>
Signed-off-by: Morten Rasmussen <morten.rasmus...@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 8014b4a..1d4059c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6841,6 +6841,7 @@ 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);
@@ -6891,11 +6892,19 @@ 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 e51145e..72150c2 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