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Commit e722d8da authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Ingo Molnar
Browse files

profile: Convert to hotplug state machine 



Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs. A lot of code is removed because
the for-loop is used and create_hash_tables() is removed since its purpose
is covered by the startup / teardown hooks.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153337.649867675@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 24f73b99

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ enum cpuhp_state { 
	CPUHP_X86_APB_DEAD,

	CPUHP_WORKQUEUE_PREP,

	CPUHP_HRTIMERS_PREPARE,

	CPUHP_PROFILE_PREPARE,

	CPUHP_TIMERS_DEAD,

	CPUHP_NOTIFY_PREPARE,

	CPUHP_BRINGUP_CPU,

kernel/profile.c

+65 −116
Original line number Diff line number Diff line
@@ -328,68 +328,57 @@ static void do_profile_hits(int type, void *__pc, unsigned int nr_hits) 
	put_cpu();

}



static int profile_cpu_callback(struct notifier_block *info,

					unsigned long action, void *__cpu)

static int profile_dead_cpu(unsigned int cpu)

{

	int node, cpu = (unsigned long)__cpu;

	struct page *page;

	int i;



	switch (action) {

	case CPU_UP_PREPARE:

	case CPU_UP_PREPARE_FROZEN:

		node = cpu_to_mem(cpu);

		per_cpu(cpu_profile_flip, cpu) = 0;

		if (!per_cpu(cpu_profile_hits, cpu)[1]) {

			page = __alloc_pages_node(node,

					GFP_KERNEL | __GFP_ZERO,

					0);

			if (!page)

				return notifier_from_errno(-ENOMEM);

			per_cpu(cpu_profile_hits, cpu)[1] = page_address(page);

		}

		if (!per_cpu(cpu_profile_hits, cpu)[0]) {

			page = __alloc_pages_node(node,

					GFP_KERNEL | __GFP_ZERO,

					0);

			if (!page)

				goto out_free;

			per_cpu(cpu_profile_hits, cpu)[0] = page_address(page);

		}

		break;

out_free:

		page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);

		per_cpu(cpu_profile_hits, cpu)[1] = NULL;

		__free_page(page);

		return notifier_from_errno(-ENOMEM);

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		if (prof_cpu_mask != NULL)

			cpumask_set_cpu(cpu, prof_cpu_mask);

		break;

	case CPU_UP_CANCELED:

	case CPU_UP_CANCELED_FROZEN:

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

	if (prof_cpu_mask != NULL)

		cpumask_clear_cpu(cpu, prof_cpu_mask);

		if (per_cpu(cpu_profile_hits, cpu)[0]) {

			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);

			per_cpu(cpu_profile_hits, cpu)[0] = NULL;



	for (i = 0; i < 2; i++) {

		if (per_cpu(cpu_profile_hits, cpu)[i]) {

			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[i]);

			per_cpu(cpu_profile_hits, cpu)[i] = NULL;

			__free_page(page);

		}

		if (per_cpu(cpu_profile_hits, cpu)[1]) {

			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);

			per_cpu(cpu_profile_hits, cpu)[1] = NULL;

			__free_page(page);

	}

		break;

	return 0;

}



static int profile_prepare_cpu(unsigned int cpu)

{

	int i, node = cpu_to_mem(cpu);

	struct page *page;



	per_cpu(cpu_profile_flip, cpu) = 0;



	for (i = 0; i < 2; i++) {

		if (per_cpu(cpu_profile_hits, cpu)[i])

			continue;



		page = __alloc_pages_node(node, GFP_KERNEL | __GFP_ZERO, 0);

		if (!page) {

			profile_dead_cpu(cpu);

			return -ENOMEM;

		}

	return NOTIFY_OK;

		per_cpu(cpu_profile_hits, cpu)[i] = page_address(page);



	}

	return 0;

}



static int profile_online_cpu(unsigned int cpu)

{

	if (prof_cpu_mask != NULL)

		cpumask_set_cpu(cpu, prof_cpu_mask);



	return 0;

}



#else /* !CONFIG_SMP */

#define profile_flip_buffers()		do { } while (0)

#define profile_discard_flip_buffers()	do { } while (0)

#define profile_cpu_callback		NULL



static void do_profile_hits(int type, void *__pc, unsigned int nr_hits)

{
@@ -531,83 +520,43 @@ static const struct file_operations proc_profile_operations = { 
	.llseek		= default_llseek,

};



#ifdef CONFIG_SMP

static void profile_nop(void *unused)

{

}



static int create_hash_tables(void)

int __ref create_proc_profile(void)

{

	int cpu;



	for_each_online_cpu(cpu) {

		int node = cpu_to_mem(cpu);

		struct page *page;



		page = __alloc_pages_node(node,

				GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,

				0);

		if (!page)

			goto out_cleanup;

		per_cpu(cpu_profile_hits, cpu)[1]

				= (struct profile_hit *)page_address(page);

		page = __alloc_pages_node(node,

				GFP_KERNEL | __GFP_ZERO | __GFP_THISNODE,

				0);

		if (!page)

			goto out_cleanup;

		per_cpu(cpu_profile_hits, cpu)[0]

				= (struct profile_hit *)page_address(page);

	}

	return 0;

out_cleanup:

	prof_on = 0;

	smp_mb();

	on_each_cpu(profile_nop, NULL, 1);

	for_each_online_cpu(cpu) {

		struct page *page;



		if (per_cpu(cpu_profile_hits, cpu)[0]) {

			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[0]);

			per_cpu(cpu_profile_hits, cpu)[0] = NULL;

			__free_page(page);

		}

		if (per_cpu(cpu_profile_hits, cpu)[1]) {

			page = virt_to_page(per_cpu(cpu_profile_hits, cpu)[1]);

			per_cpu(cpu_profile_hits, cpu)[1] = NULL;

			__free_page(page);

		}

	}

	return -1;

}

#else

#define create_hash_tables()			({ 0; })

	struct proc_dir_entry *entry;

#ifdef CONFIG_SMP

	enum cpuhp_state online_state;

#endif



int __ref create_proc_profile(void) /* false positive from hotcpu_notifier */

{

	struct proc_dir_entry *entry;

	int err = 0;



	if (!prof_on)

		return 0;

#ifdef CONFIG_SMP

	err = cpuhp_setup_state(CPUHP_PROFILE_PREPARE, "PROFILE_PREPARE",

				profile_prepare_cpu, profile_dead_cpu);

	if (err)

		return err;



	cpu_notifier_register_begin();



	if (create_hash_tables()) {

		err = -ENOMEM;

		goto out;

	}



	err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "AP_PROFILE_ONLINE",

				profile_online_cpu, NULL);

	if (err < 0)

		goto err_state_prep;

	online_state = err;

	err = 0;

#endif

	entry = proc_create("profile", S_IWUSR | S_IRUGO,

			    NULL, &proc_profile_operations);

	if (!entry)

		goto out;

		goto err_state_onl;

	proc_set_size(entry, (1 + prof_len) * sizeof(atomic_t));

	__hotcpu_notifier(profile_cpu_callback, 0);



out:

	cpu_notifier_register_done();

	return err;

err_state_onl:

#ifdef CONFIG_SMP

	cpuhp_remove_state(online_state);

err_state_prep:

	cpuhp_remove_state(CPUHP_PROFILE_PREPARE);

#endif

	return err;

}

subsys_initcall(create_proc_profile);