[mirror_ubuntu-focal-kernel.git] / 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 {
	CPU_IDLE,
	CPU_NOT_IDLE,
	CPU_NEWLY_IDLE,
	CPU_MAX_IDLE_TYPES
};

extern void wake_up_if_idle(int cpu);

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

static inline void __current_set_polling(void)
{
	set_thread_flag(TIF_POLLING_NRFLAG);
}

static inline bool __must_check current_set_polling_and_test(void)
{
	__current_set_polling();

	/*
	 * Polling state must be visible before we test NEED_RESCHED,
	 * paired by resched_curr()
	 */
	smp_mb__after_atomic();

	return unlikely(tif_need_resched());
}

static inline void __current_clr_polling(void)
{
	clear_thread_flag(TIF_POLLING_NRFLAG);
}

static inline bool __must_check current_clr_polling_and_test(void)
{
	__current_clr_polling();

	/*
	 * Polling state must be visible before we test NEED_RESCHED,
	 * paired by resched_curr()
	 */
	smp_mb__after_atomic();

	return unlikely(tif_need_resched());
}

#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 inline void current_clr_polling(void)
{
	__current_clr_polling();

	/*
	 * Ensure we check TIF_NEED_RESCHED after we clear the polling bit.
	 * Once the bit is cleared, we'll get IPIs with every new
	 * TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also
	 * fold.
	 */
	smp_mb(); /* paired with resched_curr() */

	preempt_fold_need_resched();
}

#endif /* _LINUX_SCHED_IDLE_H */
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
4c822698 IM	2	#ifndef _LINUX_SCHED_IDLE_H
	3	#define _LINUX_SCHED_IDLE_H
	4
	5	#include <linux/sched.h>
	6
b768917d IM	7	enum cpu_idle_type {
	8	CPU_IDLE,
	9	CPU_NOT_IDLE,
	10	CPU_NEWLY_IDLE,
	11	CPU_MAX_IDLE_TYPES
	12	};
	13
4437722b IM	14	extern void wake_up_if_idle(int cpu);
4437722b IM	15
5dbe91de IM	16	/*
	17	* Idle thread specific functions to determine the need_resched
	18	* polling state.
	19	*/
	20	#ifdef TIF_POLLING_NRFLAG
5dbe91de IM	21
	22	static inline void __current_set_polling(void)
	23	{
	24	set_thread_flag(TIF_POLLING_NRFLAG);
	25	}
	26
	27	static inline bool __must_check current_set_polling_and_test(void)
	28	{
	29	__current_set_polling();
	30
	31	/*
	32	* Polling state must be visible before we test NEED_RESCHED,
	33	* paired by resched_curr()
	34	*/
	35	smp_mb__after_atomic();
	36
	37	return unlikely(tif_need_resched());
	38	}
	39
	40	static inline void __current_clr_polling(void)
	41	{
	42	clear_thread_flag(TIF_POLLING_NRFLAG);
	43	}
	44
	45	static inline bool __must_check current_clr_polling_and_test(void)
	46	{
	47	__current_clr_polling();
	48
	49	/*
	50	* Polling state must be visible before we test NEED_RESCHED,
	51	* paired by resched_curr()
	52	*/
	53	smp_mb__after_atomic();
	54
	55	return unlikely(tif_need_resched());
	56	}
	57
	58	#else
5dbe91de IM	59	static inline void __current_set_polling(void) { }
	60	static inline void __current_clr_polling(void) { }
	61
	62	static inline bool __must_check current_set_polling_and_test(void)
	63	{
	64	return unlikely(tif_need_resched());
	65	}
	66	static inline bool __must_check current_clr_polling_and_test(void)
	67	{
	68	return unlikely(tif_need_resched());
	69	}
	70	#endif
	71
	72	static inline void current_clr_polling(void)
	73	{
	74	__current_clr_polling();
	75
	76	/*
	77	* Ensure we check TIF_NEED_RESCHED after we clear the polling bit.
	78	* Once the bit is cleared, we'll get IPIs with every new
	79	* TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also
	80	* fold.
	81	*/
	82	smp_mb(); /* paired with resched_curr() */
	83
	84	preempt_fold_need_resched();
	85	}
	86
4c822698	87	#endif /* _LINUX_SCHED_IDLE_H */