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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

include/linux/cpu.h

+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,

kernel/sched/core.c

+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);