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

Morten Rasmussen
2016-05-23T10:58:42Z

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.

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 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