Commit fa17b507 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched: Wrap scheduler p->cpus_allowed access 



This task is preparatory for the migrate_disable() implementation, but
stands on its own and provides a cleanup.

It currently only converts those sites required for task-placement.
Kosaki-san once mentioned replacing cpus_allowed with a proper
cpumask_t instead of the NR_CPUS sized array it currently is, that
would also require something like this.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Link: http://lkml.kernel.org/n/tip-e42skvaddos99psip0vce41o@git.kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 6eb57e0d

kernel/sched.c

+4 −4
Original line number Diff line number Diff line
@@ -2544,11 +2544,11 @@ static int select_fallback_rq(int cpu, struct task_struct *p) 


	/* Look for allowed, online CPU in same node. */

	for_each_cpu_and(dest_cpu, nodemask, cpu_active_mask)

		if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed))

		if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))

			return dest_cpu;



	/* Any allowed, online CPU? */

	dest_cpu = cpumask_any_and(&p->cpus_allowed, cpu_active_mask);

	dest_cpu = cpumask_any_and(tsk_cpus_allowed(p), cpu_active_mask);

	if (dest_cpu < nr_cpu_ids)

		return dest_cpu;
@@ -2585,7 +2585,7 @@ int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) 
	 * [ this allows ->select_task() to simply return task_cpu(p) and

	 *   not worry about this generic constraint ]

	 */

	if (unlikely(!cpumask_test_cpu(cpu, &p->cpus_allowed) ||

	if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) ||

		     !cpu_online(cpu)))

		cpu = select_fallback_rq(task_cpu(p), p);
@@ -6262,7 +6262,7 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) 
	if (task_cpu(p) != src_cpu)

		goto done;

	/* Affinity changed (again). */

	if (!cpumask_test_cpu(dest_cpu, &p->cpus_allowed))

	if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p)))

		goto fail;



	/*

kernel/sched_fair.c

+6 −6
Original line number Diff line number Diff line
@@ -2183,7 +2183,7 @@ find_idlest_group(struct sched_domain *sd, struct task_struct *p, 


		/* Skip over this group if it has no CPUs allowed */

		if (!cpumask_intersects(sched_group_cpus(group),

					&p->cpus_allowed))

					tsk_cpus_allowed(p)))

			continue;



		local_group = cpumask_test_cpu(this_cpu,
@@ -2229,7 +2229,7 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) 
	int i;



	/* Traverse only the allowed CPUs */

	for_each_cpu_and(i, sched_group_cpus(group), &p->cpus_allowed) {

	for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) {

		load = weighted_cpuload(i);



		if (load < min_load || (load == min_load && i == this_cpu)) {
@@ -2273,7 +2273,7 @@ static int select_idle_sibling(struct task_struct *p, int target) 
		if (!(sd->flags & SD_SHARE_PKG_RESOURCES))

			break;



		for_each_cpu_and(i, sched_domain_span(sd), &p->cpus_allowed) {

		for_each_cpu_and(i, sched_domain_span(sd), tsk_cpus_allowed(p)) {

			if (idle_cpu(i)) {

				target = i;

				break;
@@ -2316,7 +2316,7 @@ select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flags) 
	int sync = wake_flags & WF_SYNC;



	if (sd_flag & SD_BALANCE_WAKE) {

		if (cpumask_test_cpu(cpu, &p->cpus_allowed))

		if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))

			want_affine = 1;

		new_cpu = prev_cpu;

	}
@@ -2697,7 +2697,7 @@ int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, 
	 * 2) cannot be migrated to this CPU due to cpus_allowed, or

	 * 3) are cache-hot on their current CPU.

	 */

	if (!cpumask_test_cpu(this_cpu, &p->cpus_allowed)) {

	if (!cpumask_test_cpu(this_cpu, tsk_cpus_allowed(p))) {

		schedstat_inc(p, se.statistics.nr_failed_migrations_affine);

		return 0;

	}
@@ -4087,7 +4087,7 @@ redo: 
			 * moved to this_cpu

			 */

			if (!cpumask_test_cpu(this_cpu,

					      &busiest->curr->cpus_allowed)) {

					tsk_cpus_allowed(busiest->curr))) {

				raw_spin_unlock_irqrestore(&busiest->lock,

							    flags);

				all_pinned = 1;

kernel/sched_rt.c

+2 −2
Original line number Diff line number Diff line
@@ -1179,7 +1179,7 @@ static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep); 
static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)

{

	if (!task_running(rq, p) &&

	    (cpu < 0 || cpumask_test_cpu(cpu, &p->cpus_allowed)) &&

	    (cpu < 0 || cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) &&

	    (p->rt.nr_cpus_allowed > 1))

		return 1;

	return 0;
@@ -1324,7 +1324,7 @@ static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq) 
			 */

			if (unlikely(task_rq(task) != rq ||

				     !cpumask_test_cpu(lowest_rq->cpu,

						       &task->cpus_allowed) ||

						       tsk_cpus_allowed(task)) ||

				     task_running(rq, task) ||

				     !task->on_rq)) {

lib/smp_processor_id.c

+1 −1
Original line number Diff line number Diff line
@@ -22,7 +22,7 @@ notrace unsigned int debug_smp_processor_id(void) 
	 * Kernel threads bound to a single CPU can safely use

	 * smp_processor_id():

	 */

	if (cpumask_equal(&current->cpus_allowed, cpumask_of(this_cpu)))

	if (cpumask_equal(tsk_cpus_allowed(current), cpumask_of(this_cpu)))

		goto out;



	/*

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