Commit | Line | Data |
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457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
cf37b6b4 | 2 | /* |
a92057e1 IM |
3 | * Generic entry points for the idle threads and |
4 | * implementation of the idle task scheduling class. | |
5 | * | |
6 | * (NOTE: these are not related to SCHED_IDLE batch scheduled | |
7 | * tasks which are handled in sched/fair.c ) | |
cf37b6b4 | 8 | */ |
cf37b6b4 | 9 | |
6727ad9e CM |
10 | /* Linker adds these: start and end of __cpuidle functions */ |
11 | extern char __cpuidle_text_start[], __cpuidle_text_end[]; | |
12 | ||
faad3849 RW |
13 | /** |
14 | * sched_idle_set_state - Record idle state for the current CPU. | |
15 | * @idle_state: State to record. | |
16 | */ | |
17 | void sched_idle_set_state(struct cpuidle_state *idle_state) | |
18 | { | |
19 | idle_set_state(this_rq(), idle_state); | |
20 | } | |
21 | ||
cf37b6b4 NP |
22 | static int __read_mostly cpu_idle_force_poll; |
23 | ||
24 | void cpu_idle_poll_ctrl(bool enable) | |
25 | { | |
26 | if (enable) { | |
27 | cpu_idle_force_poll++; | |
28 | } else { | |
29 | cpu_idle_force_poll--; | |
30 | WARN_ON_ONCE(cpu_idle_force_poll < 0); | |
31 | } | |
32 | } | |
33 | ||
34 | #ifdef CONFIG_GENERIC_IDLE_POLL_SETUP | |
35 | static int __init cpu_idle_poll_setup(char *__unused) | |
36 | { | |
37 | cpu_idle_force_poll = 1; | |
a92057e1 | 38 | |
cf37b6b4 NP |
39 | return 1; |
40 | } | |
41 | __setup("nohlt", cpu_idle_poll_setup); | |
42 | ||
43 | static int __init cpu_idle_nopoll_setup(char *__unused) | |
44 | { | |
45 | cpu_idle_force_poll = 0; | |
a92057e1 | 46 | |
cf37b6b4 NP |
47 | return 1; |
48 | } | |
49 | __setup("hlt", cpu_idle_nopoll_setup); | |
50 | #endif | |
51 | ||
6727ad9e | 52 | static noinline int __cpuidle cpu_idle_poll(void) |
cf37b6b4 | 53 | { |
a01353cf | 54 | instrumentation_begin(); |
1098582a PZ |
55 | trace_cpu_idle(0, smp_processor_id()); |
56 | stop_critical_timings(); | |
a01353cf | 57 | ct_cpuidle_enter(); |
a92057e1 | 58 | |
a01353cf | 59 | raw_local_irq_enable(); |
ff6f2d29 | 60 | while (!tif_need_resched() && |
1098582a | 61 | (cpu_idle_force_poll || tick_check_broadcast_expired())) |
cf37b6b4 | 62 | cpu_relax(); |
a01353cf | 63 | raw_local_irq_disable(); |
1098582a | 64 | |
a01353cf | 65 | ct_cpuidle_exit(); |
1098582a PZ |
66 | start_critical_timings(); |
67 | trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id()); | |
a01353cf PZ |
68 | local_irq_enable(); |
69 | instrumentation_end(); | |
a92057e1 | 70 | |
cf37b6b4 NP |
71 | return 1; |
72 | } | |
73 | ||
74 | /* Weak implementations for optional arch specific functions */ | |
75 | void __weak arch_cpu_idle_prepare(void) { } | |
76 | void __weak arch_cpu_idle_enter(void) { } | |
77 | void __weak arch_cpu_idle_exit(void) { } | |
071c44e4 | 78 | void __weak __noreturn arch_cpu_idle_dead(void) { while (1); } |
cf37b6b4 NP |
79 | void __weak arch_cpu_idle(void) |
80 | { | |
81 | cpu_idle_force_poll = 1; | |
cf37b6b4 NP |
82 | } |
83 | ||
2be2a197 TG |
84 | #ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST_IDLE |
85 | DEFINE_STATIC_KEY_FALSE(arch_needs_tick_broadcast); | |
86 | ||
87 | static inline void cond_tick_broadcast_enter(void) | |
88 | { | |
89 | if (static_branch_unlikely(&arch_needs_tick_broadcast)) | |
90 | tick_broadcast_enter(); | |
91 | } | |
92 | ||
93 | static inline void cond_tick_broadcast_exit(void) | |
94 | { | |
95 | if (static_branch_unlikely(&arch_needs_tick_broadcast)) | |
96 | tick_broadcast_exit(); | |
97 | } | |
98 | #else | |
99 | static inline void cond_tick_broadcast_enter(void) { } | |
100 | static inline void cond_tick_broadcast_exit(void) { } | |
101 | #endif | |
102 | ||
827a5aef RW |
103 | /** |
104 | * default_idle_call - Default CPU idle routine. | |
105 | * | |
106 | * To use when the cpuidle framework cannot be used. | |
107 | */ | |
6727ad9e | 108 | void __cpuidle default_idle_call(void) |
82f66327 | 109 | { |
a01353cf PZ |
110 | instrumentation_begin(); |
111 | if (!current_clr_polling_and_test()) { | |
2be2a197 | 112 | cond_tick_broadcast_enter(); |
9864f5b5 | 113 | trace_cpu_idle(1, smp_processor_id()); |
63caae84 | 114 | stop_critical_timings(); |
58c644ba | 115 | |
a01353cf | 116 | ct_cpuidle_enter(); |
82f66327 | 117 | arch_cpu_idle(); |
a01353cf | 118 | ct_cpuidle_exit(); |
58c644ba | 119 | |
63caae84 | 120 | start_critical_timings(); |
9864f5b5 | 121 | trace_cpu_idle(PWR_EVENT_EXIT, smp_processor_id()); |
2be2a197 | 122 | cond_tick_broadcast_exit(); |
63caae84 | 123 | } |
a01353cf PZ |
124 | local_irq_enable(); |
125 | instrumentation_end(); | |
82f66327 RW |
126 | } |
127 | ||
10e8b11e RW |
128 | static int call_cpuidle_s2idle(struct cpuidle_driver *drv, |
129 | struct cpuidle_device *dev) | |
130 | { | |
131 | if (current_clr_polling_and_test()) | |
132 | return -EBUSY; | |
133 | ||
134 | return cpuidle_enter_s2idle(drv, dev); | |
135 | } | |
136 | ||
bcf6ad8a RW |
137 | static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev, |
138 | int next_state) | |
139 | { | |
bcf6ad8a RW |
140 | /* |
141 | * The idle task must be scheduled, it is pointless to go to idle, just | |
142 | * update no idle residency and return. | |
143 | */ | |
144 | if (current_clr_polling_and_test()) { | |
c1d51f68 | 145 | dev->last_residency_ns = 0; |
bcf6ad8a RW |
146 | local_irq_enable(); |
147 | return -EBUSY; | |
148 | } | |
149 | ||
bcf6ad8a RW |
150 | /* |
151 | * Enter the idle state previously returned by the governor decision. | |
152 | * This function will block until an interrupt occurs and will take | |
153 | * care of re-enabling the local interrupts | |
154 | */ | |
827a5aef | 155 | return cpuidle_enter(drv, dev, next_state); |
bcf6ad8a RW |
156 | } |
157 | ||
30cdd69e DL |
158 | /** |
159 | * cpuidle_idle_call - the main idle function | |
160 | * | |
161 | * NOTE: no locks or semaphores should be used here | |
82c65d60 | 162 | * |
3b03706f | 163 | * On architectures that support TIF_POLLING_NRFLAG, is called with polling |
82c65d60 AL |
164 | * set, and it returns with polling set. If it ever stops polling, it |
165 | * must clear the polling bit. | |
30cdd69e | 166 | */ |
08c373e5 | 167 | static void cpuidle_idle_call(void) |
30cdd69e | 168 | { |
9bd616e3 | 169 | struct cpuidle_device *dev = cpuidle_get_device(); |
30cdd69e | 170 | struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev); |
37352273 | 171 | int next_state, entered_state; |
30cdd69e | 172 | |
a1d028bd DL |
173 | /* |
174 | * Check if the idle task must be rescheduled. If it is the | |
c444117f | 175 | * case, exit the function after re-enabling the local irq. |
a1d028bd | 176 | */ |
c444117f | 177 | if (need_resched()) { |
8ca3c642 | 178 | local_irq_enable(); |
08c373e5 | 179 | return; |
8ca3c642 DL |
180 | } |
181 | ||
a1d028bd | 182 | /* |
ed98c349 RW |
183 | * The RCU framework needs to be told that we are entering an idle |
184 | * section, so no more rcu read side critical sections and one more | |
a1d028bd DL |
185 | * step to the grace period |
186 | */ | |
c8cc7d4d | 187 | |
82f66327 | 188 | if (cpuidle_not_available(drv, dev)) { |
ed98c349 | 189 | tick_nohz_idle_stop_tick(); |
ed98c349 | 190 | |
82f66327 RW |
191 | default_idle_call(); |
192 | goto exit_idle; | |
193 | } | |
ef2b22ac | 194 | |
38106313 | 195 | /* |
f02f4f9d | 196 | * Suspend-to-idle ("s2idle") is a system state in which all user space |
38106313 | 197 | * has been frozen, all I/O devices have been suspended and the only |
3e0de271 | 198 | * activity happens here and in interrupts (if any). In that case bypass |
3b03706f | 199 | * the cpuidle governor and go straight for the deepest idle state |
38106313 RW |
200 | * available. Possibly also suspend the local tick and the entire |
201 | * timekeeping to prevent timer interrupts from kicking us out of idle | |
202 | * until a proper wakeup interrupt happens. | |
203 | */ | |
bb8313b6 | 204 | |
c55b51a0 | 205 | if (idle_should_enter_s2idle() || dev->forced_idle_latency_limit_ns) { |
5aa9ba63 DL |
206 | u64 max_latency_ns; |
207 | ||
f02f4f9d | 208 | if (idle_should_enter_s2idle()) { |
ed98c349 | 209 | |
10e8b11e RW |
210 | entered_state = call_cpuidle_s2idle(drv, dev); |
211 | if (entered_state > 0) | |
bb8313b6 | 212 | goto exit_idle; |
ed98c349 | 213 | |
5aa9ba63 DL |
214 | max_latency_ns = U64_MAX; |
215 | } else { | |
216 | max_latency_ns = dev->forced_idle_latency_limit_ns; | |
ef2b22ac RW |
217 | } |
218 | ||
ed98c349 | 219 | tick_nohz_idle_stop_tick(); |
ed98c349 | 220 | |
5aa9ba63 | 221 | next_state = cpuidle_find_deepest_state(drv, dev, max_latency_ns); |
bcf6ad8a | 222 | call_cpuidle(drv, dev, next_state); |
ef2b22ac | 223 | } else { |
45f1ff59 RW |
224 | bool stop_tick = true; |
225 | ||
ef2b22ac RW |
226 | /* |
227 | * Ask the cpuidle framework to choose a convenient idle state. | |
228 | */ | |
45f1ff59 | 229 | next_state = cpuidle_select(drv, dev, &stop_tick); |
554c8aa8 | 230 | |
7059b366 | 231 | if (stop_tick || tick_nohz_tick_stopped()) |
554c8aa8 RW |
232 | tick_nohz_idle_stop_tick(); |
233 | else | |
234 | tick_nohz_idle_retain_tick(); | |
235 | ||
bcf6ad8a RW |
236 | entered_state = call_cpuidle(drv, dev, next_state); |
237 | /* | |
238 | * Give the governor an opportunity to reflect on the outcome | |
239 | */ | |
ef2b22ac | 240 | cpuidle_reflect(dev, entered_state); |
bcf6ad8a | 241 | } |
37352273 PZ |
242 | |
243 | exit_idle: | |
8ca3c642 | 244 | __current_set_polling(); |
30cdd69e | 245 | |
a1d028bd | 246 | /* |
37352273 | 247 | * It is up to the idle functions to reenable local interrupts |
a1d028bd | 248 | */ |
c8cc7d4d DL |
249 | if (WARN_ON_ONCE(irqs_disabled())) |
250 | local_irq_enable(); | |
30cdd69e | 251 | } |
30cdd69e | 252 | |
cf37b6b4 NP |
253 | /* |
254 | * Generic idle loop implementation | |
82c65d60 AL |
255 | * |
256 | * Called with polling cleared. | |
cf37b6b4 | 257 | */ |
c1de45ca | 258 | static void do_idle(void) |
cf37b6b4 | 259 | { |
54b933c6 | 260 | int cpu = smp_processor_id(); |
c6f88654 VG |
261 | |
262 | /* | |
263 | * Check if we need to update blocked load | |
264 | */ | |
265 | nohz_run_idle_balance(cpu); | |
266 | ||
c1de45ca PZ |
267 | /* |
268 | * If the arch has a polling bit, we maintain an invariant: | |
269 | * | |
270 | * Our polling bit is clear if we're not scheduled (i.e. if rq->curr != | |
271 | * rq->idle). This means that, if rq->idle has the polling bit set, | |
272 | * then setting need_resched is guaranteed to cause the CPU to | |
273 | * reschedule. | |
274 | */ | |
cf37b6b4 | 275 | |
c1de45ca PZ |
276 | __current_set_polling(); |
277 | tick_nohz_idle_enter(); | |
cf37b6b4 | 278 | |
c1de45ca | 279 | while (!need_resched()) { |
c1de45ca | 280 | rmb(); |
cf37b6b4 | 281 | |
dd540386 FW |
282 | /* |
283 | * Interrupts shouldn't be re-enabled from that point on until | |
284 | * the CPU sleeping instruction is reached. Otherwise an interrupt | |
285 | * may fire and queue a timer that would be ignored until the CPU | |
286 | * wakes from the sleeping instruction. And testing need_resched() | |
287 | * doesn't tell about pending needed timer reprogram. | |
288 | * | |
289 | * Several cases to consider: | |
290 | * | |
291 | * - SLEEP-UNTIL-PENDING-INTERRUPT based instructions such as | |
292 | * "wfi" or "mwait" are fine because they can be entered with | |
293 | * interrupt disabled. | |
294 | * | |
295 | * - sti;mwait() couple is fine because the interrupts are | |
296 | * re-enabled only upon the execution of mwait, leaving no gap | |
297 | * in-between. | |
298 | * | |
299 | * - ROLLBACK based idle handlers with the sleeping instruction | |
300 | * called with interrupts enabled are NOT fine. In this scheme | |
301 | * when the interrupt detects it has interrupted an idle handler, | |
302 | * it rolls back to its beginning which performs the | |
303 | * need_resched() check before re-executing the sleeping | |
304 | * instruction. This can leak a pending needed timer reprogram. | |
305 | * If such a scheme is really mandatory due to the lack of an | |
306 | * appropriate CPU sleeping instruction, then a FAST-FORWARD | |
307 | * must instead be applied: when the interrupt detects it has | |
308 | * interrupted an idle handler, it must resume to the end of | |
309 | * this idle handler so that the generic idle loop is iterated | |
310 | * again to reprogram the tick. | |
311 | */ | |
e78a7614 PZ |
312 | local_irq_disable(); |
313 | ||
54b933c6 | 314 | if (cpu_is_offline(cpu)) { |
c1de45ca PZ |
315 | cpuhp_report_idle_dead(); |
316 | arch_cpu_idle_dead(); | |
cf37b6b4 | 317 | } |
06d50c65 | 318 | |
c1de45ca | 319 | arch_cpu_idle_enter(); |
43789ef3 | 320 | rcu_nocb_flush_deferred_wakeup(); |
82c65d60 AL |
321 | |
322 | /* | |
c1de45ca PZ |
323 | * In poll mode we reenable interrupts and spin. Also if we |
324 | * detected in the wakeup from idle path that the tick | |
325 | * broadcast device expired for us, we don't want to go deep | |
326 | * idle as we know that the IPI is going to arrive right away. | |
82c65d60 | 327 | */ |
2aaf709a RW |
328 | if (cpu_idle_force_poll || tick_check_broadcast_expired()) { |
329 | tick_nohz_idle_restart_tick(); | |
c1de45ca | 330 | cpu_idle_poll(); |
2aaf709a | 331 | } else { |
c1de45ca | 332 | cpuidle_idle_call(); |
2aaf709a | 333 | } |
c1de45ca | 334 | arch_cpu_idle_exit(); |
cf37b6b4 | 335 | } |
c1de45ca PZ |
336 | |
337 | /* | |
338 | * Since we fell out of the loop above, we know TIF_NEED_RESCHED must | |
339 | * be set, propagate it into PREEMPT_NEED_RESCHED. | |
340 | * | |
341 | * This is required because for polling idle loops we will not have had | |
342 | * an IPI to fold the state for us. | |
343 | */ | |
344 | preempt_set_need_resched(); | |
345 | tick_nohz_idle_exit(); | |
346 | __current_clr_polling(); | |
347 | ||
348 | /* | |
349 | * We promise to call sched_ttwu_pending() and reschedule if | |
350 | * need_resched() is set while polling is set. That means that clearing | |
351 | * polling needs to be visible before doing these things. | |
352 | */ | |
353 | smp_mb__after_atomic(); | |
354 | ||
b2a02fc4 PZ |
355 | /* |
356 | * RCU relies on this call to be done outside of an RCU read-side | |
357 | * critical section. | |
358 | */ | |
16bf5a5e | 359 | flush_smp_call_function_queue(); |
8663effb | 360 | schedule_idle(); |
d83a7cb3 JP |
361 | |
362 | if (unlikely(klp_patch_pending(current))) | |
363 | klp_update_patch_state(current); | |
cf37b6b4 NP |
364 | } |
365 | ||
6727ad9e CM |
366 | bool cpu_in_idle(unsigned long pc) |
367 | { | |
368 | return pc >= (unsigned long)__cpuidle_text_start && | |
369 | pc < (unsigned long)__cpuidle_text_end; | |
370 | } | |
371 | ||
c1de45ca PZ |
372 | struct idle_timer { |
373 | struct hrtimer timer; | |
374 | int done; | |
375 | }; | |
376 | ||
377 | static enum hrtimer_restart idle_inject_timer_fn(struct hrtimer *timer) | |
378 | { | |
379 | struct idle_timer *it = container_of(timer, struct idle_timer, timer); | |
380 | ||
381 | WRITE_ONCE(it->done, 1); | |
382 | set_tsk_need_resched(current); | |
383 | ||
384 | return HRTIMER_NORESTART; | |
385 | } | |
386 | ||
c55b51a0 | 387 | void play_idle_precise(u64 duration_ns, u64 latency_ns) |
c1de45ca PZ |
388 | { |
389 | struct idle_timer it; | |
390 | ||
391 | /* | |
392 | * Only FIFO tasks can disable the tick since they don't need the forced | |
393 | * preemption. | |
394 | */ | |
395 | WARN_ON_ONCE(current->policy != SCHED_FIFO); | |
396 | WARN_ON_ONCE(current->nr_cpus_allowed != 1); | |
397 | WARN_ON_ONCE(!(current->flags & PF_KTHREAD)); | |
398 | WARN_ON_ONCE(!(current->flags & PF_NO_SETAFFINITY)); | |
c55b51a0 | 399 | WARN_ON_ONCE(!duration_ns); |
618758ed | 400 | WARN_ON_ONCE(current->mm); |
c1de45ca PZ |
401 | |
402 | rcu_sleep_check(); | |
403 | preempt_disable(); | |
404 | current->flags |= PF_IDLE; | |
c55b51a0 | 405 | cpuidle_use_deepest_state(latency_ns); |
c1de45ca PZ |
406 | |
407 | it.done = 0; | |
98484179 | 408 | hrtimer_init_on_stack(&it.timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
c1de45ca | 409 | it.timer.function = idle_inject_timer_fn; |
c55b51a0 | 410 | hrtimer_start(&it.timer, ns_to_ktime(duration_ns), |
98484179 | 411 | HRTIMER_MODE_REL_PINNED_HARD); |
c1de45ca PZ |
412 | |
413 | while (!READ_ONCE(it.done)) | |
414 | do_idle(); | |
415 | ||
c55b51a0 | 416 | cpuidle_use_deepest_state(0); |
c1de45ca PZ |
417 | current->flags &= ~PF_IDLE; |
418 | ||
419 | preempt_fold_need_resched(); | |
420 | preempt_enable(); | |
421 | } | |
c55b51a0 | 422 | EXPORT_SYMBOL_GPL(play_idle_precise); |
c1de45ca | 423 | |
cf37b6b4 NP |
424 | void cpu_startup_entry(enum cpuhp_state state) |
425 | { | |
cff9b233 | 426 | current->flags |= PF_IDLE; |
cf37b6b4 | 427 | arch_cpu_idle_prepare(); |
8df3e07e | 428 | cpuhp_online_idle(state); |
c1de45ca PZ |
429 | while (1) |
430 | do_idle(); | |
cf37b6b4 | 431 | } |
a92057e1 IM |
432 | |
433 | /* | |
434 | * idle-task scheduling class. | |
435 | */ | |
436 | ||
437 | #ifdef CONFIG_SMP | |
438 | static int | |
3aef1551 | 439 | select_task_rq_idle(struct task_struct *p, int cpu, int flags) |
a92057e1 IM |
440 | { |
441 | return task_cpu(p); /* IDLE tasks as never migrated */ | |
442 | } | |
6e2df058 PZ |
443 | |
444 | static int | |
445 | balance_idle(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) | |
446 | { | |
447 | return WARN_ON_ONCE(1); | |
448 | } | |
a92057e1 IM |
449 | #endif |
450 | ||
451 | /* | |
452 | * Idle tasks are unconditionally rescheduled: | |
453 | */ | |
e23edc86 | 454 | static void wakeup_preempt_idle(struct rq *rq, struct task_struct *p, int flags) |
a92057e1 IM |
455 | { |
456 | resched_curr(rq); | |
457 | } | |
458 | ||
6e2df058 | 459 | static void put_prev_task_idle(struct rq *rq, struct task_struct *prev) |
03b7fad1 PZ |
460 | { |
461 | } | |
462 | ||
a0e813f2 | 463 | static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool first) |
a92057e1 | 464 | { |
a92057e1 IM |
465 | update_idle_core(rq); |
466 | schedstat_inc(rq->sched_goidle); | |
03b7fad1 PZ |
467 | } |
468 | ||
21f56ffe PZ |
469 | #ifdef CONFIG_SMP |
470 | static struct task_struct *pick_task_idle(struct rq *rq) | |
471 | { | |
472 | return rq->idle; | |
473 | } | |
474 | #endif | |
475 | ||
98c2f700 | 476 | struct task_struct *pick_next_task_idle(struct rq *rq) |
a92057e1 | 477 | { |
03b7fad1 PZ |
478 | struct task_struct *next = rq->idle; |
479 | ||
a0e813f2 | 480 | set_next_task_idle(rq, next, true); |
a92057e1 | 481 | |
03b7fad1 | 482 | return next; |
a92057e1 IM |
483 | } |
484 | ||
485 | /* | |
486 | * It is not legal to sleep in the idle task - print a warning | |
487 | * message if some code attempts to do it: | |
488 | */ | |
489 | static void | |
490 | dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags) | |
491 | { | |
5cb9eaa3 | 492 | raw_spin_rq_unlock_irq(rq); |
a92057e1 IM |
493 | printk(KERN_ERR "bad: scheduling from the idle thread!\n"); |
494 | dump_stack(); | |
5cb9eaa3 | 495 | raw_spin_rq_lock_irq(rq); |
a92057e1 IM |
496 | } |
497 | ||
a92057e1 IM |
498 | /* |
499 | * scheduler tick hitting a task of our scheduling class. | |
500 | * | |
501 | * NOTE: This function can be called remotely by the tick offload that | |
502 | * goes along full dynticks. Therefore no local assumption can be made | |
503 | * and everything must be accessed through the @rq and @curr passed in | |
504 | * parameters. | |
505 | */ | |
506 | static void task_tick_idle(struct rq *rq, struct task_struct *curr, int queued) | |
507 | { | |
508 | } | |
509 | ||
a92057e1 IM |
510 | static void switched_to_idle(struct rq *rq, struct task_struct *p) |
511 | { | |
512 | BUG(); | |
513 | } | |
514 | ||
515 | static void | |
516 | prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio) | |
517 | { | |
518 | BUG(); | |
519 | } | |
520 | ||
a92057e1 IM |
521 | static void update_curr_idle(struct rq *rq) |
522 | { | |
523 | } | |
524 | ||
525 | /* | |
526 | * Simple, special scheduling class for the per-CPU idle tasks: | |
527 | */ | |
43c31ac0 PZ |
528 | DEFINE_SCHED_CLASS(idle) = { |
529 | ||
a92057e1 IM |
530 | /* no enqueue/yield_task for idle tasks */ |
531 | ||
532 | /* dequeue is not valid, we print a debug message there: */ | |
533 | .dequeue_task = dequeue_task_idle, | |
534 | ||
e23edc86 | 535 | .wakeup_preempt = wakeup_preempt_idle, |
a92057e1 IM |
536 | |
537 | .pick_next_task = pick_next_task_idle, | |
538 | .put_prev_task = put_prev_task_idle, | |
03b7fad1 | 539 | .set_next_task = set_next_task_idle, |
a92057e1 IM |
540 | |
541 | #ifdef CONFIG_SMP | |
6e2df058 | 542 | .balance = balance_idle, |
21f56ffe | 543 | .pick_task = pick_task_idle, |
a92057e1 IM |
544 | .select_task_rq = select_task_rq_idle, |
545 | .set_cpus_allowed = set_cpus_allowed_common, | |
546 | #endif | |
547 | ||
a92057e1 IM |
548 | .task_tick = task_tick_idle, |
549 | ||
a92057e1 IM |
550 | .prio_changed = prio_changed_idle, |
551 | .switched_to = switched_to_idle, | |
552 | .update_curr = update_curr_idle, | |
553 | }; |