Line data    Source code

       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             : 
       7             : enum cpu_idle_type {
       8             :         CPU_IDLE,
       9             :         CPU_NOT_IDLE,
      10             :         CPU_NEWLY_IDLE,
      11             :         CPU_MAX_IDLE_TYPES
      12             : };
      13             : 
      14             : extern 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             : 
      22       22244 : static inline void __current_set_polling(void)
      23             : {
      24       22244 :         set_thread_flag(TIF_POLLING_NRFLAG);
      25             : }
      26             : 
      27           0 : static inline bool __must_check current_set_polling_and_test(void)
      28             : {
      29           0 :         __current_set_polling();
      30             : 
      31             :         /*
      32             :          * Polling state must be visible before we test NEED_RESCHED,
      33             :          * paired by resched_curr()
      34             :          */
      35           0 :         smp_mb__after_atomic();
      36             : 
      37           0 :         return unlikely(tif_need_resched());
      38             : }
      39             : 
      40       22205 : static inline void __current_clr_polling(void)
      41             : {
      42        6874 :         clear_thread_flag(TIF_POLLING_NRFLAG);
      43             : }
      44             : 
      45       15331 : static inline bool __must_check current_clr_polling_and_test(void)
      46             : {
      47       15331 :         __current_clr_polling();
      48             : 
      49             :         /*
      50             :          * Polling state must be visible before we test NEED_RESCHED,
      51             :          * paired by resched_curr()
      52             :          */
      53       15415 :         smp_mb__after_atomic();
      54             : 
      55       15415 :         return unlikely(tif_need_resched());
      56             : }
      57             : 
      58             : #else
      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             : 
      87             : #endif /* _LINUX_SCHED_IDLE_H */