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Commit 32b2dd00 authored by Pavankumar Kondeti's avatar Pavankumar Kondeti
Browse files

core_ctl: Harden the adjustment_possible() check for unisolation 



When the need for CPUs is more than the active CPUs and there are some
isolated CPUs, we wakeup the core_ctl thread to unisolate some CPUs.
The core_ctl task can't unisolate any CPU if all of them are isolated
by other clients. Track the number of isolated CPUs by core_ctl and
wakeup the core_ctl task when adjustment is really possible.

Change-Id: I11ef10860532df25cbde572aabd4b925320db8fe
Signed-off-by: default avatarPavankumar Kondeti <pkondeti@codeaurora.org>
parent 0824857a

kernel/sched/core_ctl.c

+23 −2
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ struct cluster_data { 
	unsigned int busy_down_thres[MAX_CPUS_PER_CLUSTER];

	unsigned int active_cpus;

	unsigned int num_cpus;

	unsigned int nr_isolated_cpus;

	cpumask_t cpu_mask;

	unsigned int need_cpus;

	unsigned int task_thres;
@@ -293,6 +294,9 @@ static ssize_t show_global_state(const struct cluster_data *state, char *buf) 
			"\tActive CPUs: %u\n", get_active_cpu_count(cluster));

		count += snprintf(buf + count, PAGE_SIZE - count,

				"\tNeed CPUs: %u\n", cluster->need_cpus);

		count += snprintf(buf + count, PAGE_SIZE - count,

				"\tNr isolated CPUs: %u\n",

						cluster->nr_isolated_cpus);

		count += snprintf(buf + count, PAGE_SIZE - count,

				"\tBoost: %u\n", (unsigned int) cluster->boost);

	}
@@ -527,7 +531,7 @@ static bool adjustment_possible(const struct cluster_data *cluster, 
							unsigned int need)

{

	return (need < cluster->active_cpus || (need > cluster->active_cpus &&

	    sched_isolate_count(&cluster->cpu_mask, false)));

						cluster->nr_isolated_cpus));

}



static bool eval_need(struct cluster_data *cluster)
@@ -718,6 +722,7 @@ static void try_to_isolate(struct cluster_data *cluster, unsigned int need) 
	struct cpu_data *c, *tmp;

	unsigned long flags;

	unsigned int num_cpus = cluster->num_cpus;

	unsigned int nr_isolated = 0;



	/*

	 * Protect against entry being removed (and added at tail) by other
@@ -742,12 +747,14 @@ static void try_to_isolate(struct cluster_data *cluster, unsigned int need) 
		if (!sched_isolate_cpu(c->cpu)) {

			c->isolated_by_us = true;

			move_cpu_lru(c);

			nr_isolated++;

		} else {

			pr_debug("Unable to isolate CPU%u\n", c->cpu);

		}

		cluster->active_cpus = get_active_cpu_count(cluster);

		spin_lock_irqsave(&state_lock, flags);

	}

	cluster->nr_isolated_cpus += nr_isolated;

	spin_unlock_irqrestore(&state_lock, flags);



	/*
@@ -757,6 +764,7 @@ static void try_to_isolate(struct cluster_data *cluster, unsigned int need) 
	if (cluster->active_cpus <= cluster->max_cpus)

		return;



	nr_isolated = 0;

	num_cpus = cluster->num_cpus;

	spin_lock_irqsave(&state_lock, flags);

	list_for_each_entry_safe(c, tmp, &cluster->lru, sib) {
@@ -774,12 +782,14 @@ static void try_to_isolate(struct cluster_data *cluster, unsigned int need) 
		if (!sched_isolate_cpu(c->cpu)) {

			c->isolated_by_us = true;

			move_cpu_lru(c);

			nr_isolated++;

		} else {

			pr_debug("Unable to isolate CPU%u\n", c->cpu);

		}

		cluster->active_cpus = get_active_cpu_count(cluster);

		spin_lock_irqsave(&state_lock, flags);

	}

	cluster->nr_isolated_cpus += nr_isolated;

	spin_unlock_irqrestore(&state_lock, flags);



}
@@ -790,6 +800,7 @@ static void __try_to_unisolate(struct cluster_data *cluster, 
	struct cpu_data *c, *tmp;

	unsigned long flags;

	unsigned int num_cpus = cluster->num_cpus;

	unsigned int nr_unisolated = 0;



	/*

	 * Protect against entry being removed (and added at tail) by other
@@ -814,12 +825,14 @@ static void __try_to_unisolate(struct cluster_data *cluster, 
		if (!sched_unisolate_cpu(c->cpu)) {

			c->isolated_by_us = false;

			move_cpu_lru(c);

			nr_unisolated++;

		} else {

			pr_debug("Unable to unisolate CPU%u\n", c->cpu);

		}

		cluster->active_cpus = get_active_cpu_count(cluster);

		spin_lock_irqsave(&state_lock, flags);

	}

	cluster->nr_isolated_cpus -= nr_unisolated;

	spin_unlock_irqrestore(&state_lock, flags);

}
@@ -885,6 +898,8 @@ static int __ref cpu_callback(struct notifier_block *nfb, 
	struct cpu_data *state = &per_cpu(cpu_state, cpu);

	struct cluster_data *cluster = state->cluster;

	unsigned int need;

	bool do_wakeup, unisolated = false;

	unsigned long flags;



	if (unlikely(!cluster || !cluster->inited))

		return NOTIFY_DONE;
@@ -910,6 +925,7 @@ static int __ref cpu_callback(struct notifier_block *nfb, 
		if (state->isolated_by_us) {

			sched_unisolate_cpu_unlocked(cpu);

			state->isolated_by_us = false;

			unisolated = true;

		}



		/* Move a CPU to the end of the LRU when it goes offline. */
@@ -923,7 +939,12 @@ static int __ref cpu_callback(struct notifier_block *nfb, 
	}



	need = apply_limits(cluster, cluster->need_cpus);

	if (adjustment_possible(cluster, need))

	spin_lock_irqsave(&state_lock, flags);

	if (unisolated)

		cluster->nr_isolated_cpus--;

	do_wakeup = adjustment_possible(cluster, need);

	spin_unlock_irqrestore(&state_lock, flags);

	if (do_wakeup)

		wake_up_core_ctl_thread(cluster);



	return NOTIFY_OK;