Commit 5438da97 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
Browse files

mm/vmstat: Convert to hotplug state machine 



Install the callbacks via the state machine, but do not invoke them as we
can initialize the node state without calling the callbacks on all online
CPUs.

start_shepherd_timer() is now called outside the get_online_cpus() block
which is safe as it only operates on cpu possible mask.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: rt@linutronix.de
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20161129145221.ffc3kg3hd7lxiwj6@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 4c501327

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ enum cpuhp_state { 
	CPUHP_VIRT_NET_DEAD,

	CPUHP_SLUB_DEAD,

	CPUHP_MM_WRITEBACK_DEAD,

	CPUHP_MM_VMSTAT_DEAD,

	CPUHP_SOFTIRQ_DEAD,

	CPUHP_NET_MVNETA_DEAD,

	CPUHP_CPUIDLE_DEAD,

mm/vmstat.c

+35 −41
Original line number Diff line number Diff line
@@ -1728,64 +1728,58 @@ static void __init init_cpu_node_state(void) 
	}

}



static void vmstat_cpu_dead(int node)

static int vmstat_cpu_online(unsigned int cpu)

{

	const struct cpumask *node_cpus;



	node_cpus = cpumask_of_node(node);

	if (cpumask_weight(node_cpus) > 0)

		return;

	refresh_zone_stat_thresholds();

	node_set_state(cpu_to_node(cpu), N_CPU);

	return 0;

}



	node_clear_state(node, N_CPU);

static int vmstat_cpu_down_prep(unsigned int cpu)

{

	cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));

	return 0;

}



/*

 * Use the cpu notifier to insure that the thresholds are recalculated

 * when necessary.

 */

static int vmstat_cpuup_callback(struct notifier_block *nfb,

		unsigned long action,

		void *hcpu)

static int vmstat_cpu_dead(unsigned int cpu)

{

	long cpu = (long)hcpu;

	const struct cpumask *node_cpus;

	int node;



	node = cpu_to_node(cpu);



	switch (action) {

	case CPU_ONLINE:

	case CPU_ONLINE_FROZEN:

		refresh_zone_stat_thresholds();

		node_set_state(cpu_to_node(cpu), N_CPU);

		break;

	case CPU_DOWN_PREPARE:

	case CPU_DOWN_PREPARE_FROZEN:

		cancel_delayed_work_sync(&per_cpu(vmstat_work, cpu));

		break;

	case CPU_DOWN_FAILED:

	case CPU_DOWN_FAILED_FROZEN:

		break;

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

	refresh_zone_stat_thresholds();

		vmstat_cpu_dead(cpu_to_node(cpu));

		break;

	default:

		break;

	}

	return NOTIFY_OK;

	node_cpus = cpumask_of_node(node);

	if (cpumask_weight(node_cpus) > 0)

		return 0;



	node_clear_state(node, N_CPU);

	return 0;

}



static struct notifier_block vmstat_notifier =

	{ &vmstat_cpuup_callback, NULL, 0 };

#endif



static int __init setup_vmstat(void)

{

#ifdef CONFIG_SMP

	cpu_notifier_register_begin();

	__register_cpu_notifier(&vmstat_notifier);

	int ret;



	ret = cpuhp_setup_state_nocalls(CPUHP_MM_VMSTAT_DEAD, "mm/vmstat:dead",

					NULL, vmstat_cpu_dead);

	if (ret < 0)

		pr_err("vmstat: failed to register 'dead' hotplug state\n");



	ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "mm/vmstat:online",

					vmstat_cpu_online,

					vmstat_cpu_down_prep);

	if (ret < 0)

		pr_err("vmstat: failed to register 'online' hotplug state\n");



	get_online_cpus();

	init_cpu_node_state();

	put_online_cpus();



	start_shepherd_timer();

	cpu_notifier_register_done();

#endif

#ifdef CONFIG_PROC_FS

	proc_create("buddyinfo", S_IRUGO, NULL, &fragmentation_file_operations);

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