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Commit 16b26943 authored by Xunlei Pang's avatar Xunlei Pang Committed by Ingo Molnar
Browse files

sched/deadline: Modify cpudl::free_cpus to reflect rd->online 



Currently, cpudl::free_cpus contains all CPUs during init, see
cpudl_init(). When calling cpudl_find(), we have to add rd->span
to avoid selecting the cpu outside the current root domain, because
cpus_allowed cannot be depended on when performing clustered
scheduling using the cpuset, see find_later_rq().

This patch adds cpudl_set_freecpu() and cpudl_clear_freecpu() for
changing cpudl::free_cpus when doing rq_online_dl()/rq_offline_dl(),
so we can avoid the rd->span operation when calling cpudl_find()
in find_later_rq().

Signed-off-by: default avatarXunlei Pang <pang.xunlei@linaro.org>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1421642980-10045-1-git-send-email-pang.xunlei@linaro.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent ff6f2d29

kernel/sched/cpudeadline.c

+24 −4
Original line number Diff line number Diff line
@@ -107,7 +107,9 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p, 
	int best_cpu = -1;

	const struct sched_dl_entity *dl_se = &p->dl;



	if (later_mask && cpumask_and(later_mask, later_mask, cp->free_cpus)) {

	if (later_mask &&

	    cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed) &&

	    cpumask_and(later_mask, later_mask, cpu_active_mask)) {

		best_cpu = cpumask_any(later_mask);

		goto out;

	} else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
@@ -185,6 +187,26 @@ void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid) 
	raw_spin_unlock_irqrestore(&cp->lock, flags);

}



/*

 * cpudl_set_freecpu - Set the cpudl.free_cpus

 * @cp: the cpudl max-heap context

 * @cpu: rd attached cpu

 */

void cpudl_set_freecpu(struct cpudl *cp, int cpu)

{

	cpumask_set_cpu(cpu, cp->free_cpus);

}



/*

 * cpudl_clear_freecpu - Clear the cpudl.free_cpus

 * @cp: the cpudl max-heap context

 * @cpu: rd attached cpu

 */

void cpudl_clear_freecpu(struct cpudl *cp, int cpu)

{

	cpumask_clear_cpu(cpu, cp->free_cpus);

}



/*

 * cpudl_init - initialize the cpudl structure

 * @cp: the cpudl max-heap context
@@ -203,7 +225,7 @@ int cpudl_init(struct cpudl *cp) 
	if (!cp->elements)

		return -ENOMEM;



	if (!alloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {

	if (!zalloc_cpumask_var(&cp->free_cpus, GFP_KERNEL)) {

		kfree(cp->elements);

		return -ENOMEM;

	}
@@ -211,8 +233,6 @@ int cpudl_init(struct cpudl *cp) 
	for_each_possible_cpu(i)

		cp->elements[i].idx = IDX_INVALID;



	cpumask_setall(cp->free_cpus);



	return 0;

}

kernel/sched/cpudeadline.h

+2 −0
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p, 
	       struct cpumask *later_mask);

void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid);

int cpudl_init(struct cpudl *cp);

void cpudl_set_freecpu(struct cpudl *cp, int cpu);

void cpudl_clear_freecpu(struct cpudl *cp, int cpu);

void cpudl_cleanup(struct cpudl *cp);

#endif /* CONFIG_SMP */

kernel/sched/deadline.c

+2 −3
Original line number Diff line number Diff line
@@ -1165,9 +1165,6 @@ static int find_later_rq(struct task_struct *task) 
	 * We have to consider system topology and task affinity

	 * first, then we can look for a suitable cpu.

	 */

	cpumask_copy(later_mask, task_rq(task)->rd->span);

	cpumask_and(later_mask, later_mask, cpu_active_mask);

	cpumask_and(later_mask, later_mask, &task->cpus_allowed);

	best_cpu = cpudl_find(&task_rq(task)->rd->cpudl,

			task, later_mask);

	if (best_cpu == -1)
@@ -1562,6 +1559,7 @@ static void rq_online_dl(struct rq *rq) 
	if (rq->dl.overloaded)

		dl_set_overload(rq);



	cpudl_set_freecpu(&rq->rd->cpudl, rq->cpu);

	if (rq->dl.dl_nr_running > 0)

		cpudl_set(&rq->rd->cpudl, rq->cpu, rq->dl.earliest_dl.curr, 1);

}
@@ -1573,6 +1571,7 @@ static void rq_offline_dl(struct rq *rq) 
		dl_clear_overload(rq);



	cpudl_set(&rq->rd->cpudl, rq->cpu, 0, 0);

	cpudl_clear_freecpu(&rq->rd->cpudl, rq->cpu);

}



void init_sched_dl_class(void)