linux/include/linux/sched/idle.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SCHED_IDLE_H
#define _LINUX_SCHED_IDLE_H

#include <linux/sched.h>

enum cpu_idle_type { … };

#ifdef CONFIG_SMP
extern void wake_up_if_idle(int cpu);
#else
static inline void wake_up_if_idle(int cpu) { }
#endif

/*
 * Idle thread specific functions to determine the need_resched
 * polling state.
 */
#ifdef TIF_POLLING_NRFLAG

#ifdef _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H

static __always_inline void __current_set_polling(void)
{ … }

static __always_inline void __current_clr_polling(void)
{ … }

#else

static __always_inline void __current_set_polling(void)
{
	set_bit(TIF_POLLING_NRFLAG,
		(unsigned long *)(&current_thread_info()->flags));
}

static __always_inline void __current_clr_polling(void)
{
	clear_bit(TIF_POLLING_NRFLAG,
		  (unsigned long *)(&current_thread_info()->flags));
}

#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H */

static __always_inline bool __must_check current_set_polling_and_test(void)
{ … }

static __always_inline bool __must_check current_clr_polling_and_test(void)
{ … }

#else
static inline void __current_set_polling(void) { }
static inline void __current_clr_polling(void) { }

static inline bool __must_check current_set_polling_and_test(void)
{
	return unlikely(tif_need_resched());
}
static inline bool __must_check current_clr_polling_and_test(void)
{
	return unlikely(tif_need_resched());
}
#endif

static __always_inline void current_clr_polling(void)
{ … }

#endif /* _LINUX_SCHED_IDLE_H */