1 /* 2 * Copyright 2008-2011, Ingo Weinhold, ingo_weinhold@gmx.de. 3 * Copyright 2005-2010, Axel Dörfler, axeld@pinc-software.de. 4 * Distributed under the terms of the MIT License. 5 */ 6 #ifndef KERNEL_SCHEDULER_H 7 #define KERNEL_SCHEDULER_H 8 9 10 #include <cpu.h> 11 #include <int.h> 12 #include <smp.h> 13 #include <thread_types.h> 14 15 16 struct scheduling_analysis; 17 struct SchedulerListener; 18 19 20 struct scheduler_ops { 21 /*! Enqueues the thread in the ready-to-run queue. 22 The caller must hold the scheduler lock (with disabled interrupts). 23 */ 24 void (*enqueue_in_run_queue)(Thread* thread); 25 26 /*! Selects a thread from the ready-to-run queue and, if that's not the 27 calling thread, switches the current CPU's context to run the selected 28 thread. 29 If it's the same thread, the thread will just continue to run. 30 In either case, unless the thread is dead or is sleeping/waiting 31 indefinitely, the function will eventually return. 32 The caller must hold the scheduler lock (with disabled interrupts). 33 */ 34 void (*reschedule)(void); 35 36 /*! Sets the given thread's priority. 37 The thread may be running or may be in the ready-to-run queue. 38 The caller must hold the scheduler lock (with disabled interrupts). 39 */ 40 void (*set_thread_priority)(Thread* thread, int32 priority); 41 bigtime_t (*estimate_max_scheduling_latency)(Thread* thread); 42 43 /*! Called when the Thread structure is first created. 44 Per-thread housekeeping resources can be allocated. 45 Interrupts must be enabled. 46 */ 47 status_t (*on_thread_create)(Thread* thread, bool idleThread); 48 49 /*! Called when a Thread structure is initialized and made ready for 50 use. 51 The per-thread housekeeping data structures are reset, if needed. 52 The caller must hold the scheduler lock (with disabled interrupts). 53 */ 54 void (*on_thread_init)(Thread* thread); 55 56 /*! Called when a Thread structure is freed. 57 Frees up any per-thread resources allocated on the scheduler's part. The 58 function may be called even if on_thread_create() failed. 59 Interrupts must be enabled. 60 */ 61 void (*on_thread_destroy)(Thread* thread); 62 63 /*! Called in the early boot process to start thread scheduling on the 64 current CPU. 65 The function is called once for each CPU. 66 Interrupts must be disabled, but the caller must not hold the scheduler 67 lock. 68 */ 69 void (*start)(void); 70 }; 71 72 extern struct scheduler_ops* gScheduler; 73 extern spinlock gSchedulerLock; 74 75 #define scheduler_enqueue_in_run_queue(thread) \ 76 gScheduler->enqueue_in_run_queue(thread) 77 #define scheduler_set_thread_priority(thread, priority) \ 78 gScheduler->set_thread_priority(thread, priority) 79 #define scheduler_reschedule() gScheduler->reschedule() 80 #define scheduler_start() gScheduler->start() 81 #define scheduler_on_thread_create(thread, idleThread) \ 82 gScheduler->on_thread_create(thread, idleThread) 83 #define scheduler_on_thread_init(thread) \ 84 gScheduler->on_thread_init(thread) 85 #define scheduler_on_thread_destroy(thread) \ 86 gScheduler->on_thread_destroy(thread) 87 88 #ifdef __cplusplus 89 extern "C" { 90 #endif 91 92 void scheduler_add_listener(struct SchedulerListener* listener); 93 void scheduler_remove_listener(struct SchedulerListener* listener); 94 95 void scheduler_init(void); 96 void scheduler_enable_scheduling(void); 97 98 bigtime_t _user_estimate_max_scheduling_latency(thread_id thread); 99 status_t _user_analyze_scheduling(bigtime_t from, bigtime_t until, void* buffer, 100 size_t size, struct scheduling_analysis* analysis); 101 102 #ifdef __cplusplus 103 } 104 #endif 105 106 107 /*! Reschedules, if necessary. 108 The caller must hold the scheduler lock (with disabled interrupts). 109 */ 110 static inline void 111 scheduler_reschedule_if_necessary_locked() 112 { 113 if (gCPU[smp_get_current_cpu()].invoke_scheduler) 114 scheduler_reschedule(); 115 } 116 117 118 /*! Reschedules, if necessary. 119 Is a no-op, if interrupts are disabled. 120 */ 121 static inline void 122 scheduler_reschedule_if_necessary() 123 { 124 if (are_interrupts_enabled()) { 125 cpu_status state = disable_interrupts(); 126 acquire_spinlock(&gSchedulerLock); 127 128 scheduler_reschedule_if_necessary_locked(); 129 130 release_spinlock(&gSchedulerLock); 131 restore_interrupts(state); 132 } 133 } 134 135 136 #endif /* KERNEL_SCHEDULER_H */ 137