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Commit 135fb3e1 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

sched: Consolidate the notifier maze



We can maintain the ordering of the scheduler cpu hotplug functionality nicely
in one notifer. Get rid of the maze.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent e26fbffd
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+4 −8
Original line number Diff line number Diff line
@@ -61,19 +61,15 @@ struct notifier_block;
enum {
	/*
	 * SCHED_ACTIVE marks a cpu which is coming up active during
	 * CPU_ONLINE and CPU_DOWN_FAILED and must be the first
	 * notifier.  CPUSET_ACTIVE adjusts cpuset according to
	 * cpu_active mask right after SCHED_ACTIVE.  During
	 * CPU_DOWN_PREPARE, SCHED_INACTIVE and CPUSET_INACTIVE are
	 * ordered in the similar way.
	 * CPU_ONLINE and CPU_DOWN_FAILED and must be the first notifier.  Is
	 * also cpuset according to cpu_active mask right after activating the
	 * cpu. During CPU_DOWN_PREPARE, SCHED_INACTIVE reversed the operation.
	 *
	 * This ordering guarantees consistent cpu_active mask and
	 * migration behavior to all cpu notifiers.
	 */
	CPU_PRI_SCHED_ACTIVE	= INT_MAX,
	CPU_PRI_CPUSET_ACTIVE	= INT_MAX - 1,
	CPU_PRI_SCHED_INACTIVE	= INT_MIN + 1,
	CPU_PRI_CPUSET_INACTIVE	= INT_MIN,
	CPU_PRI_SCHED_INACTIVE	= INT_MIN,

	/* migration should happen before other stuff but after perf */
	CPU_PRI_PERF		= 20,
+69 −105
Original line number Diff line number Diff line
@@ -5482,39 +5482,6 @@ static void set_cpu_rq_start_time(unsigned int cpu)
	rq->age_stamp = sched_clock_cpu(cpu);
}

static int sched_cpu_active(struct notifier_block *nfb,
				      unsigned long action, void *hcpu)
{
	int cpu = (long)hcpu;

	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_DOWN_FAILED:
		set_cpu_active(cpu, true);
		return NOTIFY_OK;

	default:
		return NOTIFY_DONE;
	}
}

static int sched_cpu_inactive(struct notifier_block *nfb,
					unsigned long action, void *hcpu)
{
	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_DOWN_PREPARE:
		set_cpu_active((long)hcpu, false);
		return NOTIFY_OK;
	default:
		return NOTIFY_DONE;
	}
}

int sched_cpu_starting(unsigned int cpu)
{
	set_cpu_rq_start_time(cpu);
	return 0;
}

static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */

#ifdef CONFIG_SCHED_DEBUG
@@ -6662,10 +6629,13 @@ static void sched_init_numa(void)
	init_numa_topology_type();
}

static void sched_domains_numa_masks_set(int cpu)
static void sched_domains_numa_masks_set(unsigned int cpu)
{
	int i, j;
	int node = cpu_to_node(cpu);
	int i, j;

	if (!sched_smp_initialized)
		return;

	for (i = 0; i < sched_domains_numa_levels; i++) {
		for (j = 0; j < nr_node_ids; j++) {
@@ -6675,54 +6645,23 @@ static void sched_domains_numa_masks_set(int cpu)
	}
}

static void sched_domains_numa_masks_clear(int cpu)
static void sched_domains_numa_masks_clear(unsigned int cpu)
{
	int i, j;

	if (!sched_smp_initialized)
		return;

	for (i = 0; i < sched_domains_numa_levels; i++) {
		for (j = 0; j < nr_node_ids; j++)
			cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]);
	}
}

/*
 * Update sched_domains_numa_masks[level][node] array when new cpus
 * are onlined.
 */
static int sched_domains_numa_masks_update(struct notifier_block *nfb,
					   unsigned long action,
					   void *hcpu)
{
	int cpu = (long)hcpu;

	if (!sched_smp_initialized)
		return NOTIFY_DONE;

	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_ONLINE:
		sched_domains_numa_masks_set(cpu);
		break;

	case CPU_DEAD:
		sched_domains_numa_masks_clear(cpu);
		break;

	default:
		return NOTIFY_DONE;
	}

	return NOTIFY_OK;
}
#else
static inline void sched_init_numa(void)
{
}

static int sched_domains_numa_masks_update(struct notifier_block *nfb,
					   unsigned long action,
					   void *hcpu)
{
	return 0;
}
static inline void sched_init_numa(void) { }
static void sched_domains_numa_masks_set(unsigned int cpu) { }
static void sched_domains_numa_masks_clear(unsigned int cpu) { }
#endif /* CONFIG_NUMA */

static int __sdt_alloc(const struct cpumask *cpu_map)
@@ -7112,16 +7051,12 @@ static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */
 * If we come here as part of a suspend/resume, don't touch cpusets because we
 * want to restore it back to its original state upon resume anyway.
 */
static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
			     void *hcpu)
static void cpuset_cpu_active(bool frozen)
{
	if (!sched_smp_initialized)
		return NOTIFY_DONE;

	switch (action) {
	case CPU_ONLINE_FROZEN:
	case CPU_DOWN_FAILED_FROZEN:
		return;

	if (frozen) {
		/*
		 * num_cpus_frozen tracks how many CPUs are involved in suspend
		 * resume sequence. As long as this is not the last online
@@ -7131,38 +7066,28 @@ static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
		num_cpus_frozen--;
		if (likely(num_cpus_frozen)) {
			partition_sched_domains(1, NULL, NULL);
			break;
			return;
		}

		/*
		 * This is the last CPU online operation. So fall through and
		 * restore the original sched domains by considering the
		 * cpuset configurations.
		 */

	case CPU_ONLINE:
		cpuset_update_active_cpus(true);
		break;
	default:
		return NOTIFY_DONE;
	}
	return NOTIFY_OK;
	cpuset_update_active_cpus(true);
}

static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
			       void *hcpu)
static int cpuset_cpu_inactive(unsigned int cpu, bool frozen)
{
	unsigned long flags;
	long cpu = (long)hcpu;
	struct dl_bw *dl_b;
	bool overflow;
	int cpus;

	if (!sched_smp_initialized)
		return NOTIFY_DONE;
		return 0;

	switch (action) {
	case CPU_DOWN_PREPARE:
	if (!frozen) {
		rcu_read_lock_sched();
		dl_b = dl_bw_of(cpu);

@@ -7174,17 +7099,60 @@ static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
		rcu_read_unlock_sched();

		if (overflow)
			return notifier_from_errno(-EBUSY);
			return -EBUSY;
		cpuset_update_active_cpus(false);
		break;
	case CPU_DOWN_PREPARE_FROZEN:
	} else {
		num_cpus_frozen++;
		partition_sched_domains(1, NULL, NULL);
		break;
	}
	return 0;
}

static int sched_cpu_active(struct notifier_block *nfb, unsigned long action,
			    void *hcpu)
{
	unsigned int cpu = (unsigned long)hcpu;

	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_DOWN_FAILED:
	case CPU_ONLINE:
		set_cpu_active(cpu, true);
		sched_domains_numa_masks_set(cpu);
		cpuset_cpu_active(action & CPU_TASKS_FROZEN);
		return NOTIFY_OK;
	default:
		return NOTIFY_DONE;
	}
}

static int sched_cpu_inactive(struct notifier_block *nfb,
					unsigned long action, void *hcpu)
{
	unsigned int cpu = (unsigned long)hcpu;
	int ret;

	switch (action & ~CPU_TASKS_FROZEN) {
	case CPU_DOWN_PREPARE:
		set_cpu_active(cpu, false);
		ret = cpuset_cpu_inactive(cpu, action & CPU_TASKS_FROZEN);
		if (ret) {
			set_cpu_active(cpu, true);
			return notifier_from_errno(ret);
		}
		return NOTIFY_OK;

	case CPU_DEAD:
		sched_domains_numa_masks_clear(cpu);
		return NOTIFY_OK;
	default:
		return NOTIFY_DONE;
	}
}

int sched_cpu_starting(unsigned int cpu)
{
	set_cpu_rq_start_time(cpu);
	return 0;
}

void __init sched_init_smp(void)
@@ -7236,10 +7204,6 @@ static int __init migration_init(void)
	cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
	cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);

	hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE);
	hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
	hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);

	return 0;
}
early_initcall(migration_init);