sched: convert check_preempt_equal_prio to cpumask_var_t.
Impact: stack reduction for large NR_CPUS
Dynamically allocating cpumasks (when CONFIG_CPUMASK_OFFSTACK) saves
stack space.
We simply return if the allocation fails: since we don't use it we
could just pass NULL to cpupri_find and have it handle that.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 820fc42..1fa1362 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -805,17 +805,20 @@
static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
{
- cpumask_t mask;
+ cpumask_var_t mask;
if (rq->curr->rt.nr_cpus_allowed == 1)
return;
- if (p->rt.nr_cpus_allowed != 1
- && cpupri_find(&rq->rd->cpupri, p, &mask))
+ if (!alloc_cpumask_var(&mask, GFP_ATOMIC))
return;
- if (!cpupri_find(&rq->rd->cpupri, rq->curr, &mask))
- return;
+ if (p->rt.nr_cpus_allowed != 1
+ && cpupri_find(&rq->rd->cpupri, p, mask))
+ goto free;
+
+ if (!cpupri_find(&rq->rd->cpupri, rq->curr, mask))
+ goto free;
/*
* There appears to be other cpus that can accept
@@ -824,6 +827,8 @@
*/
requeue_task_rt(rq, p, 1);
resched_task(rq->curr);
+free:
+ free_cpumask_var(mask);
}
#endif /* CONFIG_SMP */
