Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 672d3eb9 authored by Linux Build Service Account's avatar Linux Build Service Account Committed by Gerrit - the friendly Code Review server
Browse files

Merge "sched: fix wrong load_scale_factor/capacity/nr_big/small_tasks"

parents 987b0d1b 9e37153f

kernel/sched/core.c

+40 −8
Original line number Diff line number Diff line
@@ -1936,9 +1936,11 @@ static int cpufreq_notifier_policy(struct notifier_block *nb, 
{

	struct cpufreq_policy *policy = (struct cpufreq_policy *)data;

	int i;

	unsigned int min_max = min_max_freq;

	const struct cpumask *cpus = policy->related_cpus;

	int orig_min_max_freq = min_max_freq;

	unsigned int orig_min_max_freq = min_max_freq;

	unsigned int orig_max_possible_freq = max_possible_freq;

	/* Initialized to policy->max in case policy->related_cpus is empty! */

	unsigned int orig_max_freq = policy->max;



	if (val != CPUFREQ_NOTIFY)

		return 0;
@@ -1946,6 +1948,7 @@ static int cpufreq_notifier_policy(struct notifier_block *nb, 
	for_each_cpu(i, policy->related_cpus) {

		cpumask_copy(&cpu_rq(i)->freq_domain_cpumask,

			     policy->related_cpus);

		orig_max_freq = cpu_rq(i)->max_freq;

		cpu_rq(i)->min_freq = policy->min;

		cpu_rq(i)->max_freq = policy->max;

		cpu_rq(i)->max_possible_freq = policy->cpuinfo.max_freq;
@@ -1953,20 +1956,49 @@ static int cpufreq_notifier_policy(struct notifier_block *nb, 


	max_possible_freq = max(max_possible_freq, policy->cpuinfo.max_freq);

	if (min_max_freq == 1)

		min_max = UINT_MAX;

	min_max_freq = min(min_max, policy->cpuinfo.max_freq);

		min_max_freq = UINT_MAX;

	min_max_freq = min(min_max_freq, policy->cpuinfo.max_freq);

	BUG_ON(!min_max_freq);

	BUG_ON(!policy->max);



	if (min_max_freq != orig_min_max_freq)

		cpus = cpu_online_mask;

	if (orig_max_possible_freq == max_possible_freq &&

		orig_min_max_freq == min_max_freq &&

		orig_max_freq == policy->max)

			return 0;



	/*

	 * A changed min_max_freq or max_possible_freq (possible during bootup)

	 * needs to trigger re-computation of load_scale_factor and capacity for

	 * all possible cpus (even those offline). It also needs to trigger

	 * re-computation of nr_big/small_task count on all online cpus.

	 *

	 * A changed rq->max_freq otoh needs to trigger re-computation of

	 * load_scale_factor and capacity for just the cluster of cpus involved.

	 * Since small task definition depends on max_load_scale_factor, a

	 * changed load_scale_factor of one cluster could influence small_task

	 * classification of tasks in another cluster. Hence a changed

	 * rq->max_freq will need to trigger re-computation of nr_big/small_task

	 * count on all online cpus.

	 *

	 * While it should be sufficient for nr_big/small_tasks to be

	 * re-computed for only online cpus, we have inadequate context

	 * information here (in policy notifier) with regard to hotplug-safety

	 * context in which notification is issued. As a result, we can't use

	 * get_online_cpus() here, as it can lead to deadlock. Until cpufreq is

	 * fixed up to issue notification always in hotplug-safe context,

	 * re-compute nr_big/small_task for all possible cpus.

	 */



	if (orig_min_max_freq != min_max_freq ||

		orig_max_possible_freq != max_possible_freq)

			cpus = cpu_possible_mask;



	/*

	 * Changed load_scale_factor can trigger reclassification of tasks as

	 * big or small. Make this change "atomic" so that tasks are accounted

	 * properly due to changed load_scale_factor

	 */

	pre_big_small_task_count_change();

	pre_big_small_task_count_change(cpu_possible_mask);

	for_each_cpu(i, cpus) {

		struct rq *rq = cpu_rq(i);
@@ -1977,7 +2009,7 @@ static int cpufreq_notifier_policy(struct notifier_block *nb, 
	}



	update_min_max_capacity();

	post_big_small_task_count_change();

	post_big_small_task_count_change(cpu_possible_mask);



	return 0;

}

kernel/sched/fair.c

+13 −9
Original line number Diff line number Diff line
@@ -1858,13 +1858,13 @@ void fixup_nr_big_small_task(int cpu) 
}



/* Disable interrupts and grab runqueue lock of all cpus listed in @cpus */

void pre_big_small_task_count_change(void)

void pre_big_small_task_count_change(const struct cpumask *cpus)

{

	int i;



	local_irq_disable();



	for_each_online_cpu(i)

	for_each_cpu(i, cpus)

		raw_spin_lock(&cpu_rq(i)->lock);

}
@@ -1872,15 +1872,15 @@ void pre_big_small_task_count_change(void) 
 * Reinitialize 'nr_big_tasks' and 'nr_small_tasks' counters on all affected

 * cpus

 */

void post_big_small_task_count_change(void)

void post_big_small_task_count_change(const struct cpumask *cpus)

{

	int i;



	/* Assumes local_irq_disable() keeps online cpumap stable */

	for_each_online_cpu(i)

	for_each_cpu(i, cpus)

		fixup_nr_big_small_task(i);



	for_each_online_cpu(i)

	for_each_cpu(i, cpus)

		raw_spin_unlock(&cpu_rq(i)->lock);



	local_irq_enable();
@@ -1972,15 +1972,19 @@ int sched_hmp_proc_update_handler(struct ctl_table *table, int write, 
	 */

	if ((*data != old_val) &&

		(data == &sysctl_sched_upmigrate_pct ||

		data == &sysctl_sched_small_task_pct))

			pre_big_small_task_count_change();

		data == &sysctl_sched_small_task_pct)) {

			get_online_cpus();

			pre_big_small_task_count_change(cpu_online_mask);

	}



	set_hmp_defaults();



	if ((*data != old_val) &&

		(data == &sysctl_sched_upmigrate_pct ||

		data == &sysctl_sched_small_task_pct))

			post_big_small_task_count_change();

		data == &sysctl_sched_small_task_pct)) {

			post_big_small_task_count_change(cpu_online_mask);

			put_online_cpus();

	}



	return 0;

}

kernel/sched/sched.h

+2 −2
Original line number Diff line number Diff line
@@ -804,8 +804,8 @@ extern unsigned int sched_enable_power_aware; 


int mostly_idle_cpu(int cpu);

extern void check_for_migration(struct rq *rq, struct task_struct *p);

extern void pre_big_small_task_count_change(void);

extern void post_big_small_task_count_change(void);

extern void pre_big_small_task_count_change(const struct cpumask *cpus);

extern void post_big_small_task_count_change(const struct cpumask *cpus);

extern void inc_nr_big_small_task(struct rq *rq, struct task_struct *p);

extern void dec_nr_big_small_task(struct rq *rq, struct task_struct *p);

extern void set_hmp_defaults(void);