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Commit c4544dbc authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
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kernel/softirq: Convert to hotplug state machine 



Install the callbacks via the state machine.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160818125731.27256-7-bigeasy@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 1d7ac6ae

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ enum cpuhp_state { 
	CPUHP_VIRT_NET_DEAD,

	CPUHP_SLUB_DEAD,

	CPUHP_MM_WRITEBACK_DEAD,

	CPUHP_SOFTIRQ_DEAD,

	CPUHP_WORKQUEUE_PREP,

	CPUHP_POWER_NUMA_PREPARE,

	CPUHP_HRTIMERS_PREPARE,

kernel/softirq.c

+6 −21
Original line number Diff line number Diff line
@@ -700,7 +700,7 @@ void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu) 
	BUG();

}



static void takeover_tasklets(unsigned int cpu)

static int takeover_tasklets(unsigned int cpu)

{

	/* CPU is dead, so no lock needed. */

	local_irq_disable();
@@ -723,27 +723,12 @@ static void takeover_tasklets(unsigned int cpu) 
	raise_softirq_irqoff(HI_SOFTIRQ);



	local_irq_enable();

	return 0;

}

#else

#define takeover_tasklets	NULL

#endif /* CONFIG_HOTPLUG_CPU */



static int cpu_callback(struct notifier_block *nfb, unsigned long action,

			void *hcpu)

{

	switch (action) {

#ifdef CONFIG_HOTPLUG_CPU

	case CPU_DEAD:

	case CPU_DEAD_FROZEN:

		takeover_tasklets((unsigned long)hcpu);

		break;

#endif /* CONFIG_HOTPLUG_CPU */

	}

	return NOTIFY_OK;

}



static struct notifier_block cpu_nfb = {

	.notifier_call = cpu_callback

};



static struct smp_hotplug_thread softirq_threads = {

	.store			= &ksoftirqd,

	.thread_should_run	= ksoftirqd_should_run,
@@ -753,8 +738,8 @@ static struct smp_hotplug_thread softirq_threads = { 


static __init int spawn_ksoftirqd(void)

{

	register_cpu_notifier(&cpu_nfb);



	cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL,

				  takeover_tasklets);

	BUG_ON(smpboot_register_percpu_thread(&softirq_threads));



	return 0;