[RFCv5 PATCH 26/46] sched: Store system-wide maximum cpu capacity in root domain

Morten Rasmussen
2015-07-07T18:25:07Z

From: Dietmar Eggemann <dietmar.eggemann@arm.com>

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>
---
kernel/sched/core.c | 8 ++++++++
kernel/sched/sched.h | 3 +++
2 files changed, 11 insertions(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index c7fdd07..fe4b361 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6853,6 +6853,7 @@ 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;
int i, ret = -ENOMEM;

alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
@@ -6906,11 +6907,18 @@ 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();

+ rq = cpu_rq(cpumask_first(cpu_map));
+ 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 fbe2da0..9589d9e 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -553,6 +553,9 @@ 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;
--
1.9.1