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Commit 8a0cb951 authored by Pavankumar Kondeti's avatar Pavankumar Kondeti
Browse files

core_ctl: Implement not_preferred hint strictly 



Don't isolate CPUs other than not_preferred CPUs unless limits
(max_cpus) condition is not met. All CPUs are eligible for
isolation when there is no preference. This policy allows
not_preferred tunable to be used to specify which CPUs need to
be kept active.

Change-Id: I6151067e3e55e5751b16f02212d9332fc3b7809b
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
parent f92f804a

kernel/sched/core_ctl.c

+14 −1
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ struct cluster_data { 
	unsigned int active_cpus;

	unsigned int num_cpus;

	unsigned int nr_isolated_cpus;

	unsigned int nr_not_preferred_cpus;

#ifdef CONFIG_SCHED_CORE_ROTATE

	unsigned long set_max;

	unsigned long set_cur;
@@ -350,6 +351,7 @@ static ssize_t store_not_preferred(struct cluster_data *state, 
	unsigned int val[MAX_CPUS_PER_CLUSTER];

	unsigned long flags;

	int ret;

	int not_preferred_count = 0;



	ret = sscanf(buf, "%u %u %u %u %u %u\n",

			&val[0], &val[1], &val[2], &val[3],
@@ -361,7 +363,9 @@ static ssize_t store_not_preferred(struct cluster_data *state, 
	for (i = 0; i < state->num_cpus; i++) {

		c = &per_cpu(cpu_state, i + state->first_cpu);

		c->not_preferred = val[i];

		not_preferred_count += !!val[i];

	}

	state->nr_not_preferred_cpus = not_preferred_count;

	spin_unlock_irqrestore(&state_lock, flags);



	return count;
@@ -793,10 +797,18 @@ static void try_to_isolate(struct cluster_data *cluster, unsigned int need) 
			continue;

		if (cluster->active_cpus == need)

			break;

		/* Don't offline busy CPUs. */

		/* Don't isolate busy CPUs. */

		if (c->is_busy)

			continue;



		/*

		 * We isolate only the not_preferred CPUs. If none

		 * of the CPUs are selected as not_preferred, then

		 * all CPUs are eligible for isolation.

		 */

		if (cluster->nr_not_preferred_cpus && !c->not_preferred)

			continue;



		if (!should_we_isolate(c->cpu, cluster))

			continue;
@@ -1109,6 +1121,7 @@ static int cluster_init(const struct cpumask *mask) 
	cluster->set_cur = cluster->set_max - 1;

#endif

	cluster->enable = true;

	cluster->nr_not_preferred_cpus = 0;

	INIT_LIST_HEAD(&cluster->lru);

	spin_lock_init(&cluster->pending_lock);