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Commit 13b8bd0a authored by Rusty Russell's avatar Rusty Russell Committed by Ingo Molnar
Browse files

sched_rt: don't allocate cpumask in fastpath 



Impact: cleanup

As pointed out by Steven Rostedt.  Since the arg in question is
unused, we simply change cpupri_find() to accept NULL.

Reported-by: default avatarSteven Rostedt <srostedt@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
LKML-Reference: <200903251501.22664.rusty@rustcorp.com.au>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent a18b83b7

kernel/sched_cpupri.c

+3 −2
Original line number Diff line number Diff line
@@ -55,7 +55,7 @@ static int convert_prio(int prio) 
 * cpupri_find - find the best (lowest-pri) CPU in the system

 * @cp: The cpupri context

 * @p: The task

 * @lowest_mask: A mask to fill in with selected CPUs

 * @lowest_mask: A mask to fill in with selected CPUs (or NULL)

 *

 * Note: This function returns the recommended CPUs as calculated during the

 * current invokation.  By the time the call returns, the CPUs may have in
@@ -81,6 +81,7 @@ int cpupri_find(struct cpupri *cp, struct task_struct *p, 
		if (cpumask_any_and(&p->cpus_allowed, vec->mask) >= nr_cpu_ids)

			continue;



		if (lowest_mask)

			cpumask_and(lowest_mask, &p->cpus_allowed, vec->mask);

		return 1;

	}

kernel/sched_rt.c

+4 −11
Original line number Diff line number Diff line
@@ -805,20 +805,15 @@ static int select_task_rq_rt(struct task_struct *p, int sync) 


static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)

{

	cpumask_var_t mask;



	if (rq->curr->rt.nr_cpus_allowed == 1)

		return;



	if (!alloc_cpumask_var(&mask, GFP_ATOMIC))

		return;



	if (p->rt.nr_cpus_allowed != 1

	    && cpupri_find(&rq->rd->cpupri, p, mask))

		goto free;

	    && cpupri_find(&rq->rd->cpupri, p, NULL))

		return;



	if (!cpupri_find(&rq->rd->cpupri, rq->curr, mask))

		goto free;

	if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))

		return;



	/*

	 * There appears to be other cpus that can accept
@@ -827,8 +822,6 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p) 
	 */

	requeue_task_rt(rq, p, 1);

	resched_task(rq->curr);

free:

	free_cpumask_var(mask);

}



#endif /* CONFIG_SMP */