Commit bc088f9a authored by Thomas Gleixner's avatar Thomas Gleixner Committed by Peter Zijlstra
Browse files

cpu/hotplug: Remove unused state functions 



All users converted to the hotplug core mechanism.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: default avatarMichael Kelley <mikelley@microsoft.com>
Tested-by: default avatarOleksandr Natalenko <oleksandr@natalenko.name>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Tested-by: Guilherme G. Piccoli <gpiccoli@igalia.com> # Steam Deck
Link: https://lore.kernel.org/r/20230512205256.972894276@linutronix.de
parent 72b11aa7

include/linux/cpu.h

+0 −2
Original line number Diff line number Diff line
@@ -193,8 +193,6 @@ static inline void play_idle(unsigned long duration_us) 
}



#ifdef CONFIG_HOTPLUG_CPU

bool cpu_wait_death(unsigned int cpu, int seconds);

bool cpu_report_death(void);

void cpuhp_report_idle_dead(void);

#else

static inline void cpuhp_report_idle_dead(void) { }

kernel/smpboot.c

+0 −75
Original line number Diff line number Diff line
@@ -325,78 +325,3 @@ void smpboot_unregister_percpu_thread(struct smp_hotplug_thread *plug_thread) 
	cpus_read_unlock();

}

EXPORT_SYMBOL_GPL(smpboot_unregister_percpu_thread);
 


#ifndef CONFIG_HOTPLUG_CORE_SYNC

static DEFINE_PER_CPU(atomic_t, cpu_hotplug_state) = ATOMIC_INIT(CPU_POST_DEAD);



#ifdef CONFIG_HOTPLUG_CPU

/*

 * Wait for the specified CPU to exit the idle loop and die.

 */

bool cpu_wait_death(unsigned int cpu, int seconds)

{

	int jf_left = seconds * HZ;

	int oldstate;

	bool ret = true;

	int sleep_jf = 1;



	might_sleep();



	/* The outgoing CPU will normally get done quite quickly. */

	if (atomic_read(&per_cpu(cpu_hotplug_state, cpu)) == CPU_DEAD)

		goto update_state_early;

	udelay(5);



	/* But if the outgoing CPU dawdles, wait increasingly long times. */

	while (atomic_read(&per_cpu(cpu_hotplug_state, cpu)) != CPU_DEAD) {

		schedule_timeout_uninterruptible(sleep_jf);

		jf_left -= sleep_jf;

		if (jf_left <= 0)

			break;

		sleep_jf = DIV_ROUND_UP(sleep_jf * 11, 10);

	}

update_state_early:

	oldstate = atomic_read(&per_cpu(cpu_hotplug_state, cpu));

update_state:

	if (oldstate == CPU_DEAD) {

		/* Outgoing CPU died normally, update state. */

		smp_mb(); /* atomic_read() before update. */

		atomic_set(&per_cpu(cpu_hotplug_state, cpu), CPU_POST_DEAD);

	} else {

		/* Outgoing CPU still hasn't died, set state accordingly. */

		if (!atomic_try_cmpxchg(&per_cpu(cpu_hotplug_state, cpu),

					&oldstate, CPU_BROKEN))

			goto update_state;

		ret = false;

	}

	return ret;

}



/*

 * Called by the outgoing CPU to report its successful death.  Return

 * false if this report follows the surviving CPU's timing out.

 *

 * A separate "CPU_DEAD_FROZEN" is used when the surviving CPU

 * timed out.  This approach allows architectures to omit calls to

 * cpu_check_up_prepare() and cpu_set_state_online() without defeating

 * the next cpu_wait_death()'s polling loop.

 */

bool cpu_report_death(void)

{

	int oldstate;

	int newstate;

	int cpu = smp_processor_id();



	oldstate = atomic_read(&per_cpu(cpu_hotplug_state, cpu));

	do {

		if (oldstate != CPU_BROKEN)

			newstate = CPU_DEAD;

		else

			newstate = CPU_DEAD_FROZEN;

	} while (!atomic_try_cmpxchg(&per_cpu(cpu_hotplug_state, cpu),

				     &oldstate, newstate));

	return newstate == CPU_DEAD;

}



#endif /* #ifdef CONFIG_HOTPLUG_CPU */

#endif /* !CONFIG_HOTPLUG_CORE_SYNC */