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/* 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_NOT_IDLE = 0,
CPU_IDLE,
CPU_NEWLY_IDLE,
CPU_MAX_IDLE_TYPES
};
#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)
{
arch_set_bit(TIF_POLLING_NRFLAG,
(unsigned long *)(¤t_thread_info()->flags));
}
static __always_inline void __current_clr_polling(void)
{
arch_clear_bit(TIF_POLLING_NRFLAG,
(unsigned long *)(¤t_thread_info()->flags));
}
#else
static __always_inline void __current_set_polling(void)
{
set_bit(TIF_POLLING_NRFLAG,
(unsigned long *)(¤t_thread_info()->flags));
}
static __always_inline void __current_clr_polling(void)
{
clear_bit(TIF_POLLING_NRFLAG,
(unsigned long *)(¤t_thread_info()->flags));
}
#endif /* _ASM_GENERIC_BITOPS_INSTRUMENTED_ATOMIC_H */
static __always_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 __always_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 __always_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 */
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