We cache the subset of rd->span cpus that are online in rd->online to
reduce the need for runtime computation.
Signed-off-by: Gregory Haskins <[email protected]>
---
kernel/sched.c | 22 ++++++++++++++++++++++
1 files changed, 22 insertions(+), 0 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index e5c902c..c58d1bf 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -281,6 +281,7 @@ struct rt_rq {
struct root_domain {
atomic_t refcount;
cpumask_t span;
+ cpumask_t online;
};
static struct root_domain def_root_domain;
@@ -5491,6 +5492,15 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
case CPU_ONLINE_FROZEN:
/* Strictly unnecessary, as first user will wake it. */
wake_up_process(cpu_rq(cpu)->migration_thread);
+
+ /* Update our root-domain */
+ rq = cpu_rq(cpu);
+ spin_lock_irqsave(&rq->lock, flags);
+ if (rq->rd) {
+ BUG_ON(!cpu_isset(cpu, rq->rd->span));
+ cpu_set(cpu, rq->rd->online);
+ }
+ spin_unlock_irqrestore(&rq->lock, flags);
break;
#ifdef CONFIG_HOTPLUG_CPU
@@ -5539,6 +5549,17 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
}
spin_unlock_irq(&rq->lock);
break;
+
+ case CPU_DOWN_PREPARE:
+ /* Update our root-domain */
+ rq = cpu_rq(cpu);
+ spin_lock_irqsave(&rq->lock, flags);
+ if (rq->rd) {
+ BUG_ON(!cpu_isset(cpu, rq->rd->span));
+ cpu_clear(cpu, rq->rd->online);
+ }
+ spin_unlock_irqrestore(&rq->lock, flags);
+ break;
#endif
case CPU_LOCK_RELEASE:
mutex_unlock(&sched_hotcpu_mutex);
@@ -5763,6 +5784,7 @@ static void init_rootdomain(struct root_domain *rd, cpumask_t *map)
memset(rd, 0, sizeof(*rd));
rd->span = *map;
+ cpus_and(rd->online, rd->span, cpu_online_map);
}
static void init_defrootdomain(void)
-
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