1/* SPDX-License-Identifier: GPL-2.0 */ 2#ifndef _LINUX_SCHED_IDLE_H 3#define _LINUX_SCHED_IDLE_H 4 5#include <linux/sched.h> 6 7enum cpu_idle_type { 8 CPU_IDLE, 9 CPU_NOT_IDLE, 10 CPU_NEWLY_IDLE, 11 CPU_MAX_IDLE_TYPES 12}; 13 14extern void wake_up_if_idle(int cpu); 15 16/* 17 * Idle thread specific functions to determine the need_resched 18 * polling state. 19 */ 20#ifdef TIF_POLLING_NRFLAG 21 22static inline void __current_set_polling(void) 23{ 24 set_thread_flag(TIF_POLLING_NRFLAG); 25} 26 27static 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 40static inline void __current_clr_polling(void) 41{ 42 clear_thread_flag(TIF_POLLING_NRFLAG); 43} 44 45static 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 59static inline void __current_set_polling(void) { } 60static inline void __current_clr_polling(void) { } 61 62static inline bool __must_check current_set_polling_and_test(void) 63{ 64 return unlikely(tif_need_resched()); 65} 66static inline bool __must_check current_clr_polling_and_test(void) 67{ 68 return unlikely(tif_need_resched()); 69} 70#endif 71 72static 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 87#endif /* _LINUX_SCHED_IDLE_H */ 88