Commit | Line | Data |
---|---|---|
bb44e5d1 IM |
1 | /* |
2 | * Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR | |
3 | * policies) | |
4 | */ | |
5 | ||
4fd29176 | 6 | #ifdef CONFIG_SMP |
84de4274 | 7 | |
637f5085 | 8 | static inline int rt_overloaded(struct rq *rq) |
4fd29176 | 9 | { |
637f5085 | 10 | return atomic_read(&rq->rd->rto_count); |
4fd29176 | 11 | } |
84de4274 | 12 | |
4fd29176 SR |
13 | static inline void rt_set_overload(struct rq *rq) |
14 | { | |
1f11eb6a GH |
15 | if (!rq->online) |
16 | return; | |
17 | ||
637f5085 | 18 | cpu_set(rq->cpu, rq->rd->rto_mask); |
4fd29176 SR |
19 | /* |
20 | * Make sure the mask is visible before we set | |
21 | * the overload count. That is checked to determine | |
22 | * if we should look at the mask. It would be a shame | |
23 | * if we looked at the mask, but the mask was not | |
24 | * updated yet. | |
25 | */ | |
26 | wmb(); | |
637f5085 | 27 | atomic_inc(&rq->rd->rto_count); |
4fd29176 | 28 | } |
84de4274 | 29 | |
4fd29176 SR |
30 | static inline void rt_clear_overload(struct rq *rq) |
31 | { | |
1f11eb6a GH |
32 | if (!rq->online) |
33 | return; | |
34 | ||
4fd29176 | 35 | /* the order here really doesn't matter */ |
637f5085 GH |
36 | atomic_dec(&rq->rd->rto_count); |
37 | cpu_clear(rq->cpu, rq->rd->rto_mask); | |
4fd29176 | 38 | } |
73fe6aae GH |
39 | |
40 | static void update_rt_migration(struct rq *rq) | |
41 | { | |
637f5085 | 42 | if (rq->rt.rt_nr_migratory && (rq->rt.rt_nr_running > 1)) { |
cdc8eb98 GH |
43 | if (!rq->rt.overloaded) { |
44 | rt_set_overload(rq); | |
45 | rq->rt.overloaded = 1; | |
46 | } | |
47 | } else if (rq->rt.overloaded) { | |
73fe6aae | 48 | rt_clear_overload(rq); |
637f5085 GH |
49 | rq->rt.overloaded = 0; |
50 | } | |
73fe6aae | 51 | } |
4fd29176 SR |
52 | #endif /* CONFIG_SMP */ |
53 | ||
6f505b16 | 54 | static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se) |
fa85ae24 | 55 | { |
6f505b16 PZ |
56 | return container_of(rt_se, struct task_struct, rt); |
57 | } | |
58 | ||
59 | static inline int on_rt_rq(struct sched_rt_entity *rt_se) | |
60 | { | |
61 | return !list_empty(&rt_se->run_list); | |
62 | } | |
63 | ||
052f1dc7 | 64 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 | 65 | |
9f0c1e56 | 66 | static inline u64 sched_rt_runtime(struct rt_rq *rt_rq) |
6f505b16 PZ |
67 | { |
68 | if (!rt_rq->tg) | |
9f0c1e56 | 69 | return RUNTIME_INF; |
6f505b16 | 70 | |
ac086bc2 PZ |
71 | return rt_rq->rt_runtime; |
72 | } | |
73 | ||
74 | static inline u64 sched_rt_period(struct rt_rq *rt_rq) | |
75 | { | |
76 | return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period); | |
6f505b16 PZ |
77 | } |
78 | ||
79 | #define for_each_leaf_rt_rq(rt_rq, rq) \ | |
80 | list_for_each_entry(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list) | |
81 | ||
82 | static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) | |
83 | { | |
84 | return rt_rq->rq; | |
85 | } | |
86 | ||
87 | static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) | |
88 | { | |
89 | return rt_se->rt_rq; | |
90 | } | |
91 | ||
92 | #define for_each_sched_rt_entity(rt_se) \ | |
93 | for (; rt_se; rt_se = rt_se->parent) | |
94 | ||
95 | static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) | |
96 | { | |
97 | return rt_se->my_q; | |
98 | } | |
99 | ||
100 | static void enqueue_rt_entity(struct sched_rt_entity *rt_se); | |
101 | static void dequeue_rt_entity(struct sched_rt_entity *rt_se); | |
102 | ||
9f0c1e56 | 103 | static void sched_rt_rq_enqueue(struct rt_rq *rt_rq) |
6f505b16 PZ |
104 | { |
105 | struct sched_rt_entity *rt_se = rt_rq->rt_se; | |
106 | ||
107 | if (rt_se && !on_rt_rq(rt_se) && rt_rq->rt_nr_running) { | |
1020387f PZ |
108 | struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr; |
109 | ||
6f505b16 | 110 | enqueue_rt_entity(rt_se); |
1020387f PZ |
111 | if (rt_rq->highest_prio < curr->prio) |
112 | resched_task(curr); | |
6f505b16 PZ |
113 | } |
114 | } | |
115 | ||
9f0c1e56 | 116 | static void sched_rt_rq_dequeue(struct rt_rq *rt_rq) |
6f505b16 PZ |
117 | { |
118 | struct sched_rt_entity *rt_se = rt_rq->rt_se; | |
119 | ||
120 | if (rt_se && on_rt_rq(rt_se)) | |
121 | dequeue_rt_entity(rt_se); | |
122 | } | |
123 | ||
23b0fdfc PZ |
124 | static inline int rt_rq_throttled(struct rt_rq *rt_rq) |
125 | { | |
126 | return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted; | |
127 | } | |
128 | ||
129 | static int rt_se_boosted(struct sched_rt_entity *rt_se) | |
130 | { | |
131 | struct rt_rq *rt_rq = group_rt_rq(rt_se); | |
132 | struct task_struct *p; | |
133 | ||
134 | if (rt_rq) | |
135 | return !!rt_rq->rt_nr_boosted; | |
136 | ||
137 | p = rt_task_of(rt_se); | |
138 | return p->prio != p->normal_prio; | |
139 | } | |
140 | ||
d0b27fa7 PZ |
141 | #ifdef CONFIG_SMP |
142 | static inline cpumask_t sched_rt_period_mask(void) | |
143 | { | |
144 | return cpu_rq(smp_processor_id())->rd->span; | |
145 | } | |
6f505b16 | 146 | #else |
d0b27fa7 PZ |
147 | static inline cpumask_t sched_rt_period_mask(void) |
148 | { | |
149 | return cpu_online_map; | |
150 | } | |
151 | #endif | |
6f505b16 | 152 | |
d0b27fa7 PZ |
153 | static inline |
154 | struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu) | |
6f505b16 | 155 | { |
d0b27fa7 PZ |
156 | return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu]; |
157 | } | |
9f0c1e56 | 158 | |
ac086bc2 PZ |
159 | static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq) |
160 | { | |
161 | return &rt_rq->tg->rt_bandwidth; | |
162 | } | |
163 | ||
d0b27fa7 PZ |
164 | #else |
165 | ||
166 | static inline u64 sched_rt_runtime(struct rt_rq *rt_rq) | |
167 | { | |
ac086bc2 PZ |
168 | return rt_rq->rt_runtime; |
169 | } | |
170 | ||
171 | static inline u64 sched_rt_period(struct rt_rq *rt_rq) | |
172 | { | |
173 | return ktime_to_ns(def_rt_bandwidth.rt_period); | |
6f505b16 PZ |
174 | } |
175 | ||
176 | #define for_each_leaf_rt_rq(rt_rq, rq) \ | |
177 | for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL) | |
178 | ||
179 | static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) | |
180 | { | |
181 | return container_of(rt_rq, struct rq, rt); | |
182 | } | |
183 | ||
184 | static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) | |
185 | { | |
186 | struct task_struct *p = rt_task_of(rt_se); | |
187 | struct rq *rq = task_rq(p); | |
188 | ||
189 | return &rq->rt; | |
190 | } | |
191 | ||
192 | #define for_each_sched_rt_entity(rt_se) \ | |
193 | for (; rt_se; rt_se = NULL) | |
194 | ||
195 | static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se) | |
196 | { | |
197 | return NULL; | |
198 | } | |
199 | ||
9f0c1e56 | 200 | static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq) |
6f505b16 PZ |
201 | { |
202 | } | |
203 | ||
9f0c1e56 | 204 | static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq) |
6f505b16 PZ |
205 | { |
206 | } | |
207 | ||
23b0fdfc PZ |
208 | static inline int rt_rq_throttled(struct rt_rq *rt_rq) |
209 | { | |
210 | return rt_rq->rt_throttled; | |
211 | } | |
d0b27fa7 PZ |
212 | |
213 | static inline cpumask_t sched_rt_period_mask(void) | |
214 | { | |
215 | return cpu_online_map; | |
216 | } | |
217 | ||
218 | static inline | |
219 | struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu) | |
220 | { | |
221 | return &cpu_rq(cpu)->rt; | |
222 | } | |
223 | ||
ac086bc2 PZ |
224 | static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq) |
225 | { | |
226 | return &def_rt_bandwidth; | |
227 | } | |
228 | ||
6f505b16 PZ |
229 | #endif |
230 | ||
d0b27fa7 PZ |
231 | static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) |
232 | { | |
233 | int i, idle = 1; | |
234 | cpumask_t span; | |
235 | ||
236 | if (rt_b->rt_runtime == RUNTIME_INF) | |
237 | return 1; | |
238 | ||
239 | span = sched_rt_period_mask(); | |
240 | for_each_cpu_mask(i, span) { | |
241 | int enqueue = 0; | |
242 | struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i); | |
243 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
244 | ||
245 | spin_lock(&rq->lock); | |
246 | if (rt_rq->rt_time) { | |
ac086bc2 | 247 | u64 runtime; |
d0b27fa7 | 248 | |
ac086bc2 PZ |
249 | spin_lock(&rt_rq->rt_runtime_lock); |
250 | runtime = rt_rq->rt_runtime; | |
d0b27fa7 PZ |
251 | rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime); |
252 | if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) { | |
253 | rt_rq->rt_throttled = 0; | |
254 | enqueue = 1; | |
255 | } | |
256 | if (rt_rq->rt_time || rt_rq->rt_nr_running) | |
257 | idle = 0; | |
ac086bc2 | 258 | spin_unlock(&rt_rq->rt_runtime_lock); |
d0b27fa7 PZ |
259 | } |
260 | ||
261 | if (enqueue) | |
262 | sched_rt_rq_enqueue(rt_rq); | |
263 | spin_unlock(&rq->lock); | |
264 | } | |
265 | ||
266 | return idle; | |
267 | } | |
268 | ||
ac086bc2 PZ |
269 | #ifdef CONFIG_SMP |
270 | static int balance_runtime(struct rt_rq *rt_rq) | |
271 | { | |
272 | struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq); | |
273 | struct root_domain *rd = cpu_rq(smp_processor_id())->rd; | |
274 | int i, weight, more = 0; | |
275 | u64 rt_period; | |
276 | ||
277 | weight = cpus_weight(rd->span); | |
278 | ||
279 | spin_lock(&rt_b->rt_runtime_lock); | |
280 | rt_period = ktime_to_ns(rt_b->rt_period); | |
281 | for_each_cpu_mask(i, rd->span) { | |
282 | struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i); | |
283 | s64 diff; | |
284 | ||
285 | if (iter == rt_rq) | |
286 | continue; | |
287 | ||
288 | spin_lock(&iter->rt_runtime_lock); | |
289 | diff = iter->rt_runtime - iter->rt_time; | |
290 | if (diff > 0) { | |
291 | do_div(diff, weight); | |
292 | if (rt_rq->rt_runtime + diff > rt_period) | |
293 | diff = rt_period - rt_rq->rt_runtime; | |
294 | iter->rt_runtime -= diff; | |
295 | rt_rq->rt_runtime += diff; | |
296 | more = 1; | |
297 | if (rt_rq->rt_runtime == rt_period) { | |
298 | spin_unlock(&iter->rt_runtime_lock); | |
299 | break; | |
300 | } | |
301 | } | |
302 | spin_unlock(&iter->rt_runtime_lock); | |
303 | } | |
304 | spin_unlock(&rt_b->rt_runtime_lock); | |
305 | ||
306 | return more; | |
307 | } | |
308 | #endif | |
309 | ||
6f505b16 PZ |
310 | static inline int rt_se_prio(struct sched_rt_entity *rt_se) |
311 | { | |
052f1dc7 | 312 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 PZ |
313 | struct rt_rq *rt_rq = group_rt_rq(rt_se); |
314 | ||
315 | if (rt_rq) | |
316 | return rt_rq->highest_prio; | |
317 | #endif | |
318 | ||
319 | return rt_task_of(rt_se)->prio; | |
320 | } | |
321 | ||
9f0c1e56 | 322 | static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq) |
6f505b16 | 323 | { |
9f0c1e56 | 324 | u64 runtime = sched_rt_runtime(rt_rq); |
fa85ae24 | 325 | |
9f0c1e56 | 326 | if (runtime == RUNTIME_INF) |
fa85ae24 PZ |
327 | return 0; |
328 | ||
329 | if (rt_rq->rt_throttled) | |
23b0fdfc | 330 | return rt_rq_throttled(rt_rq); |
fa85ae24 | 331 | |
ac086bc2 PZ |
332 | if (sched_rt_runtime(rt_rq) >= sched_rt_period(rt_rq)) |
333 | return 0; | |
334 | ||
335 | #ifdef CONFIG_SMP | |
336 | if (rt_rq->rt_time > runtime) { | |
337 | int more; | |
338 | ||
339 | spin_unlock(&rt_rq->rt_runtime_lock); | |
340 | more = balance_runtime(rt_rq); | |
341 | spin_lock(&rt_rq->rt_runtime_lock); | |
342 | ||
343 | if (more) | |
344 | runtime = sched_rt_runtime(rt_rq); | |
345 | } | |
346 | #endif | |
347 | ||
9f0c1e56 | 348 | if (rt_rq->rt_time > runtime) { |
6f505b16 | 349 | rt_rq->rt_throttled = 1; |
23b0fdfc | 350 | if (rt_rq_throttled(rt_rq)) { |
9f0c1e56 | 351 | sched_rt_rq_dequeue(rt_rq); |
23b0fdfc PZ |
352 | return 1; |
353 | } | |
fa85ae24 PZ |
354 | } |
355 | ||
356 | return 0; | |
357 | } | |
358 | ||
bb44e5d1 IM |
359 | /* |
360 | * Update the current task's runtime statistics. Skip current tasks that | |
361 | * are not in our scheduling class. | |
362 | */ | |
a9957449 | 363 | static void update_curr_rt(struct rq *rq) |
bb44e5d1 IM |
364 | { |
365 | struct task_struct *curr = rq->curr; | |
6f505b16 PZ |
366 | struct sched_rt_entity *rt_se = &curr->rt; |
367 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); | |
bb44e5d1 IM |
368 | u64 delta_exec; |
369 | ||
370 | if (!task_has_rt_policy(curr)) | |
371 | return; | |
372 | ||
d281918d | 373 | delta_exec = rq->clock - curr->se.exec_start; |
bb44e5d1 IM |
374 | if (unlikely((s64)delta_exec < 0)) |
375 | delta_exec = 0; | |
6cfb0d5d IM |
376 | |
377 | schedstat_set(curr->se.exec_max, max(curr->se.exec_max, delta_exec)); | |
bb44e5d1 IM |
378 | |
379 | curr->se.sum_exec_runtime += delta_exec; | |
d281918d | 380 | curr->se.exec_start = rq->clock; |
d842de87 | 381 | cpuacct_charge(curr, delta_exec); |
fa85ae24 | 382 | |
354d60c2 DG |
383 | for_each_sched_rt_entity(rt_se) { |
384 | rt_rq = rt_rq_of_se(rt_se); | |
385 | ||
386 | spin_lock(&rt_rq->rt_runtime_lock); | |
387 | rt_rq->rt_time += delta_exec; | |
388 | if (sched_rt_runtime_exceeded(rt_rq)) | |
389 | resched_task(curr); | |
390 | spin_unlock(&rt_rq->rt_runtime_lock); | |
391 | } | |
bb44e5d1 IM |
392 | } |
393 | ||
6f505b16 PZ |
394 | static inline |
395 | void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
63489e45 | 396 | { |
6f505b16 PZ |
397 | WARN_ON(!rt_prio(rt_se_prio(rt_se))); |
398 | rt_rq->rt_nr_running++; | |
052f1dc7 | 399 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
6e0534f2 GH |
400 | if (rt_se_prio(rt_se) < rt_rq->highest_prio) { |
401 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
6f505b16 | 402 | rt_rq->highest_prio = rt_se_prio(rt_se); |
1f11eb6a GH |
403 | |
404 | if (rq->online) | |
405 | cpupri_set(&rq->rd->cpupri, rq->cpu, | |
406 | rt_se_prio(rt_se)); | |
6e0534f2 | 407 | } |
6f505b16 | 408 | #endif |
764a9d6f | 409 | #ifdef CONFIG_SMP |
6f505b16 PZ |
410 | if (rt_se->nr_cpus_allowed > 1) { |
411 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
73fe6aae | 412 | rq->rt.rt_nr_migratory++; |
6f505b16 | 413 | } |
73fe6aae | 414 | |
6f505b16 PZ |
415 | update_rt_migration(rq_of_rt_rq(rt_rq)); |
416 | #endif | |
052f1dc7 | 417 | #ifdef CONFIG_RT_GROUP_SCHED |
23b0fdfc PZ |
418 | if (rt_se_boosted(rt_se)) |
419 | rt_rq->rt_nr_boosted++; | |
d0b27fa7 PZ |
420 | |
421 | if (rt_rq->tg) | |
422 | start_rt_bandwidth(&rt_rq->tg->rt_bandwidth); | |
423 | #else | |
424 | start_rt_bandwidth(&def_rt_bandwidth); | |
23b0fdfc | 425 | #endif |
63489e45 SR |
426 | } |
427 | ||
6f505b16 PZ |
428 | static inline |
429 | void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) | |
63489e45 | 430 | { |
6e0534f2 GH |
431 | #ifdef CONFIG_SMP |
432 | int highest_prio = rt_rq->highest_prio; | |
433 | #endif | |
434 | ||
6f505b16 PZ |
435 | WARN_ON(!rt_prio(rt_se_prio(rt_se))); |
436 | WARN_ON(!rt_rq->rt_nr_running); | |
437 | rt_rq->rt_nr_running--; | |
052f1dc7 | 438 | #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
6f505b16 | 439 | if (rt_rq->rt_nr_running) { |
764a9d6f SR |
440 | struct rt_prio_array *array; |
441 | ||
6f505b16 PZ |
442 | WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio); |
443 | if (rt_se_prio(rt_se) == rt_rq->highest_prio) { | |
764a9d6f | 444 | /* recalculate */ |
6f505b16 PZ |
445 | array = &rt_rq->active; |
446 | rt_rq->highest_prio = | |
764a9d6f SR |
447 | sched_find_first_bit(array->bitmap); |
448 | } /* otherwise leave rq->highest prio alone */ | |
449 | } else | |
6f505b16 PZ |
450 | rt_rq->highest_prio = MAX_RT_PRIO; |
451 | #endif | |
452 | #ifdef CONFIG_SMP | |
453 | if (rt_se->nr_cpus_allowed > 1) { | |
454 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
73fe6aae | 455 | rq->rt.rt_nr_migratory--; |
6f505b16 | 456 | } |
73fe6aae | 457 | |
6e0534f2 GH |
458 | if (rt_rq->highest_prio != highest_prio) { |
459 | struct rq *rq = rq_of_rt_rq(rt_rq); | |
1f11eb6a GH |
460 | |
461 | if (rq->online) | |
462 | cpupri_set(&rq->rd->cpupri, rq->cpu, | |
463 | rt_rq->highest_prio); | |
6e0534f2 GH |
464 | } |
465 | ||
6f505b16 | 466 | update_rt_migration(rq_of_rt_rq(rt_rq)); |
764a9d6f | 467 | #endif /* CONFIG_SMP */ |
052f1dc7 | 468 | #ifdef CONFIG_RT_GROUP_SCHED |
23b0fdfc PZ |
469 | if (rt_se_boosted(rt_se)) |
470 | rt_rq->rt_nr_boosted--; | |
471 | ||
472 | WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted); | |
473 | #endif | |
63489e45 SR |
474 | } |
475 | ||
6f505b16 | 476 | static void enqueue_rt_entity(struct sched_rt_entity *rt_se) |
bb44e5d1 | 477 | { |
6f505b16 PZ |
478 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); |
479 | struct rt_prio_array *array = &rt_rq->active; | |
480 | struct rt_rq *group_rq = group_rt_rq(rt_se); | |
bb44e5d1 | 481 | |
23b0fdfc | 482 | if (group_rq && rt_rq_throttled(group_rq)) |
6f505b16 | 483 | return; |
63489e45 | 484 | |
45c01e82 GH |
485 | if (rt_se->nr_cpus_allowed == 1) |
486 | list_add_tail(&rt_se->run_list, | |
487 | array->xqueue + rt_se_prio(rt_se)); | |
488 | else | |
489 | list_add_tail(&rt_se->run_list, | |
490 | array->squeue + rt_se_prio(rt_se)); | |
491 | ||
6f505b16 | 492 | __set_bit(rt_se_prio(rt_se), array->bitmap); |
78f2c7db | 493 | |
6f505b16 PZ |
494 | inc_rt_tasks(rt_se, rt_rq); |
495 | } | |
496 | ||
497 | static void dequeue_rt_entity(struct sched_rt_entity *rt_se) | |
498 | { | |
499 | struct rt_rq *rt_rq = rt_rq_of_se(rt_se); | |
500 | struct rt_prio_array *array = &rt_rq->active; | |
501 | ||
502 | list_del_init(&rt_se->run_list); | |
45c01e82 GH |
503 | if (list_empty(array->squeue + rt_se_prio(rt_se)) |
504 | && list_empty(array->xqueue + rt_se_prio(rt_se))) | |
6f505b16 PZ |
505 | __clear_bit(rt_se_prio(rt_se), array->bitmap); |
506 | ||
507 | dec_rt_tasks(rt_se, rt_rq); | |
508 | } | |
509 | ||
510 | /* | |
511 | * Because the prio of an upper entry depends on the lower | |
512 | * entries, we must remove entries top - down. | |
6f505b16 PZ |
513 | */ |
514 | static void dequeue_rt_stack(struct task_struct *p) | |
515 | { | |
58d6c2d7 | 516 | struct sched_rt_entity *rt_se, *back = NULL; |
6f505b16 | 517 | |
58d6c2d7 PZ |
518 | rt_se = &p->rt; |
519 | for_each_sched_rt_entity(rt_se) { | |
520 | rt_se->back = back; | |
521 | back = rt_se; | |
522 | } | |
523 | ||
524 | for (rt_se = back; rt_se; rt_se = rt_se->back) { | |
525 | if (on_rt_rq(rt_se)) | |
526 | dequeue_rt_entity(rt_se); | |
527 | } | |
bb44e5d1 IM |
528 | } |
529 | ||
530 | /* | |
531 | * Adding/removing a task to/from a priority array: | |
532 | */ | |
6f505b16 PZ |
533 | static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup) |
534 | { | |
535 | struct sched_rt_entity *rt_se = &p->rt; | |
536 | ||
537 | if (wakeup) | |
538 | rt_se->timeout = 0; | |
539 | ||
540 | dequeue_rt_stack(p); | |
541 | ||
542 | /* | |
543 | * enqueue everybody, bottom - up. | |
544 | */ | |
545 | for_each_sched_rt_entity(rt_se) | |
546 | enqueue_rt_entity(rt_se); | |
6f505b16 PZ |
547 | } |
548 | ||
f02231e5 | 549 | static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep) |
bb44e5d1 | 550 | { |
6f505b16 PZ |
551 | struct sched_rt_entity *rt_se = &p->rt; |
552 | struct rt_rq *rt_rq; | |
bb44e5d1 | 553 | |
f1e14ef6 | 554 | update_curr_rt(rq); |
bb44e5d1 | 555 | |
6f505b16 PZ |
556 | dequeue_rt_stack(p); |
557 | ||
558 | /* | |
559 | * re-enqueue all non-empty rt_rq entities. | |
560 | */ | |
561 | for_each_sched_rt_entity(rt_se) { | |
562 | rt_rq = group_rt_rq(rt_se); | |
563 | if (rt_rq && rt_rq->rt_nr_running) | |
564 | enqueue_rt_entity(rt_se); | |
565 | } | |
bb44e5d1 IM |
566 | } |
567 | ||
568 | /* | |
569 | * Put task to the end of the run list without the overhead of dequeue | |
570 | * followed by enqueue. | |
45c01e82 GH |
571 | * |
572 | * Note: We always enqueue the task to the shared-queue, regardless of its | |
573 | * previous position w.r.t. exclusive vs shared. This is so that exclusive RR | |
574 | * tasks fairly round-robin with all tasks on the runqueue, not just other | |
575 | * exclusive tasks. | |
bb44e5d1 | 576 | */ |
6f505b16 PZ |
577 | static |
578 | void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se) | |
579 | { | |
580 | struct rt_prio_array *array = &rt_rq->active; | |
581 | ||
45c01e82 GH |
582 | list_del_init(&rt_se->run_list); |
583 | list_add_tail(&rt_se->run_list, array->squeue + rt_se_prio(rt_se)); | |
6f505b16 PZ |
584 | } |
585 | ||
bb44e5d1 IM |
586 | static void requeue_task_rt(struct rq *rq, struct task_struct *p) |
587 | { | |
6f505b16 PZ |
588 | struct sched_rt_entity *rt_se = &p->rt; |
589 | struct rt_rq *rt_rq; | |
bb44e5d1 | 590 | |
6f505b16 PZ |
591 | for_each_sched_rt_entity(rt_se) { |
592 | rt_rq = rt_rq_of_se(rt_se); | |
593 | requeue_rt_entity(rt_rq, rt_se); | |
594 | } | |
bb44e5d1 IM |
595 | } |
596 | ||
6f505b16 | 597 | static void yield_task_rt(struct rq *rq) |
bb44e5d1 | 598 | { |
4530d7ab | 599 | requeue_task_rt(rq, rq->curr); |
bb44e5d1 IM |
600 | } |
601 | ||
e7693a36 | 602 | #ifdef CONFIG_SMP |
318e0893 GH |
603 | static int find_lowest_rq(struct task_struct *task); |
604 | ||
e7693a36 GH |
605 | static int select_task_rq_rt(struct task_struct *p, int sync) |
606 | { | |
318e0893 GH |
607 | struct rq *rq = task_rq(p); |
608 | ||
609 | /* | |
e1f47d89 SR |
610 | * If the current task is an RT task, then |
611 | * try to see if we can wake this RT task up on another | |
612 | * runqueue. Otherwise simply start this RT task | |
613 | * on its current runqueue. | |
614 | * | |
615 | * We want to avoid overloading runqueues. Even if | |
616 | * the RT task is of higher priority than the current RT task. | |
617 | * RT tasks behave differently than other tasks. If | |
618 | * one gets preempted, we try to push it off to another queue. | |
619 | * So trying to keep a preempting RT task on the same | |
620 | * cache hot CPU will force the running RT task to | |
621 | * a cold CPU. So we waste all the cache for the lower | |
622 | * RT task in hopes of saving some of a RT task | |
623 | * that is just being woken and probably will have | |
624 | * cold cache anyway. | |
318e0893 | 625 | */ |
17b3279b | 626 | if (unlikely(rt_task(rq->curr)) && |
6f505b16 | 627 | (p->rt.nr_cpus_allowed > 1)) { |
318e0893 GH |
628 | int cpu = find_lowest_rq(p); |
629 | ||
630 | return (cpu == -1) ? task_cpu(p) : cpu; | |
631 | } | |
632 | ||
633 | /* | |
634 | * Otherwise, just let it ride on the affined RQ and the | |
635 | * post-schedule router will push the preempted task away | |
636 | */ | |
e7693a36 GH |
637 | return task_cpu(p); |
638 | } | |
639 | #endif /* CONFIG_SMP */ | |
640 | ||
45c01e82 GH |
641 | static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, |
642 | struct rt_rq *rt_rq); | |
643 | ||
bb44e5d1 IM |
644 | /* |
645 | * Preempt the current task with a newly woken task if needed: | |
646 | */ | |
647 | static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p) | |
648 | { | |
45c01e82 | 649 | if (p->prio < rq->curr->prio) { |
bb44e5d1 | 650 | resched_task(rq->curr); |
45c01e82 GH |
651 | return; |
652 | } | |
653 | ||
654 | #ifdef CONFIG_SMP | |
655 | /* | |
656 | * If: | |
657 | * | |
658 | * - the newly woken task is of equal priority to the current task | |
659 | * - the newly woken task is non-migratable while current is migratable | |
660 | * - current will be preempted on the next reschedule | |
661 | * | |
662 | * we should check to see if current can readily move to a different | |
663 | * cpu. If so, we will reschedule to allow the push logic to try | |
664 | * to move current somewhere else, making room for our non-migratable | |
665 | * task. | |
666 | */ | |
667 | if((p->prio == rq->curr->prio) | |
668 | && p->rt.nr_cpus_allowed == 1 | |
669 | && rq->curr->rt.nr_cpus_allowed != 1 | |
670 | && pick_next_rt_entity(rq, &rq->rt) != &rq->curr->rt) { | |
671 | cpumask_t mask; | |
672 | ||
673 | if (cpupri_find(&rq->rd->cpupri, rq->curr, &mask)) | |
674 | /* | |
675 | * There appears to be other cpus that can accept | |
676 | * current, so lets reschedule to try and push it away | |
677 | */ | |
678 | resched_task(rq->curr); | |
679 | } | |
680 | #endif | |
bb44e5d1 IM |
681 | } |
682 | ||
6f505b16 PZ |
683 | static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq, |
684 | struct rt_rq *rt_rq) | |
bb44e5d1 | 685 | { |
6f505b16 PZ |
686 | struct rt_prio_array *array = &rt_rq->active; |
687 | struct sched_rt_entity *next = NULL; | |
bb44e5d1 IM |
688 | struct list_head *queue; |
689 | int idx; | |
690 | ||
691 | idx = sched_find_first_bit(array->bitmap); | |
6f505b16 | 692 | BUG_ON(idx >= MAX_RT_PRIO); |
bb44e5d1 | 693 | |
45c01e82 GH |
694 | queue = array->xqueue + idx; |
695 | if (!list_empty(queue)) | |
696 | next = list_entry(queue->next, struct sched_rt_entity, | |
697 | run_list); | |
698 | else { | |
699 | queue = array->squeue + idx; | |
700 | next = list_entry(queue->next, struct sched_rt_entity, | |
701 | run_list); | |
702 | } | |
326587b8 | 703 | |
6f505b16 PZ |
704 | return next; |
705 | } | |
bb44e5d1 | 706 | |
6f505b16 PZ |
707 | static struct task_struct *pick_next_task_rt(struct rq *rq) |
708 | { | |
709 | struct sched_rt_entity *rt_se; | |
710 | struct task_struct *p; | |
711 | struct rt_rq *rt_rq; | |
bb44e5d1 | 712 | |
6f505b16 PZ |
713 | rt_rq = &rq->rt; |
714 | ||
715 | if (unlikely(!rt_rq->rt_nr_running)) | |
716 | return NULL; | |
717 | ||
23b0fdfc | 718 | if (rt_rq_throttled(rt_rq)) |
6f505b16 PZ |
719 | return NULL; |
720 | ||
721 | do { | |
722 | rt_se = pick_next_rt_entity(rq, rt_rq); | |
326587b8 | 723 | BUG_ON(!rt_se); |
6f505b16 PZ |
724 | rt_rq = group_rt_rq(rt_se); |
725 | } while (rt_rq); | |
726 | ||
727 | p = rt_task_of(rt_se); | |
728 | p->se.exec_start = rq->clock; | |
729 | return p; | |
bb44e5d1 IM |
730 | } |
731 | ||
31ee529c | 732 | static void put_prev_task_rt(struct rq *rq, struct task_struct *p) |
bb44e5d1 | 733 | { |
f1e14ef6 | 734 | update_curr_rt(rq); |
bb44e5d1 IM |
735 | p->se.exec_start = 0; |
736 | } | |
737 | ||
681f3e68 | 738 | #ifdef CONFIG_SMP |
6f505b16 | 739 | |
e8fa1362 SR |
740 | /* Only try algorithms three times */ |
741 | #define RT_MAX_TRIES 3 | |
742 | ||
743 | static int double_lock_balance(struct rq *this_rq, struct rq *busiest); | |
744 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep); | |
745 | ||
f65eda4f SR |
746 | static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu) |
747 | { | |
748 | if (!task_running(rq, p) && | |
73fe6aae | 749 | (cpu < 0 || cpu_isset(cpu, p->cpus_allowed)) && |
6f505b16 | 750 | (p->rt.nr_cpus_allowed > 1)) |
f65eda4f SR |
751 | return 1; |
752 | return 0; | |
753 | } | |
754 | ||
e8fa1362 | 755 | /* Return the second highest RT task, NULL otherwise */ |
79064fbf | 756 | static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu) |
e8fa1362 | 757 | { |
6f505b16 PZ |
758 | struct task_struct *next = NULL; |
759 | struct sched_rt_entity *rt_se; | |
760 | struct rt_prio_array *array; | |
761 | struct rt_rq *rt_rq; | |
e8fa1362 SR |
762 | int idx; |
763 | ||
6f505b16 PZ |
764 | for_each_leaf_rt_rq(rt_rq, rq) { |
765 | array = &rt_rq->active; | |
766 | idx = sched_find_first_bit(array->bitmap); | |
767 | next_idx: | |
768 | if (idx >= MAX_RT_PRIO) | |
769 | continue; | |
770 | if (next && next->prio < idx) | |
771 | continue; | |
45c01e82 | 772 | list_for_each_entry(rt_se, array->squeue + idx, run_list) { |
6f505b16 PZ |
773 | struct task_struct *p = rt_task_of(rt_se); |
774 | if (pick_rt_task(rq, p, cpu)) { | |
775 | next = p; | |
776 | break; | |
777 | } | |
778 | } | |
779 | if (!next) { | |
780 | idx = find_next_bit(array->bitmap, MAX_RT_PRIO, idx+1); | |
781 | goto next_idx; | |
782 | } | |
f65eda4f SR |
783 | } |
784 | ||
e8fa1362 SR |
785 | return next; |
786 | } | |
787 | ||
788 | static DEFINE_PER_CPU(cpumask_t, local_cpu_mask); | |
789 | ||
6e1254d2 GH |
790 | static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask) |
791 | { | |
792 | int first; | |
793 | ||
794 | /* "this_cpu" is cheaper to preempt than a remote processor */ | |
795 | if ((this_cpu != -1) && cpu_isset(this_cpu, *mask)) | |
796 | return this_cpu; | |
797 | ||
798 | first = first_cpu(*mask); | |
799 | if (first != NR_CPUS) | |
800 | return first; | |
801 | ||
802 | return -1; | |
803 | } | |
804 | ||
805 | static int find_lowest_rq(struct task_struct *task) | |
806 | { | |
807 | struct sched_domain *sd; | |
808 | cpumask_t *lowest_mask = &__get_cpu_var(local_cpu_mask); | |
809 | int this_cpu = smp_processor_id(); | |
810 | int cpu = task_cpu(task); | |
06f90dbd | 811 | |
6e0534f2 GH |
812 | if (task->rt.nr_cpus_allowed == 1) |
813 | return -1; /* No other targets possible */ | |
6e1254d2 | 814 | |
6e0534f2 GH |
815 | if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask)) |
816 | return -1; /* No targets found */ | |
6e1254d2 GH |
817 | |
818 | /* | |
819 | * At this point we have built a mask of cpus representing the | |
820 | * lowest priority tasks in the system. Now we want to elect | |
821 | * the best one based on our affinity and topology. | |
822 | * | |
823 | * We prioritize the last cpu that the task executed on since | |
824 | * it is most likely cache-hot in that location. | |
825 | */ | |
826 | if (cpu_isset(cpu, *lowest_mask)) | |
827 | return cpu; | |
828 | ||
829 | /* | |
830 | * Otherwise, we consult the sched_domains span maps to figure | |
831 | * out which cpu is logically closest to our hot cache data. | |
832 | */ | |
833 | if (this_cpu == cpu) | |
834 | this_cpu = -1; /* Skip this_cpu opt if the same */ | |
835 | ||
836 | for_each_domain(cpu, sd) { | |
837 | if (sd->flags & SD_WAKE_AFFINE) { | |
838 | cpumask_t domain_mask; | |
839 | int best_cpu; | |
840 | ||
841 | cpus_and(domain_mask, sd->span, *lowest_mask); | |
842 | ||
843 | best_cpu = pick_optimal_cpu(this_cpu, | |
844 | &domain_mask); | |
845 | if (best_cpu != -1) | |
846 | return best_cpu; | |
847 | } | |
848 | } | |
849 | ||
850 | /* | |
851 | * And finally, if there were no matches within the domains | |
852 | * just give the caller *something* to work with from the compatible | |
853 | * locations. | |
854 | */ | |
855 | return pick_optimal_cpu(this_cpu, lowest_mask); | |
07b4032c GH |
856 | } |
857 | ||
858 | /* Will lock the rq it finds */ | |
4df64c0b | 859 | static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq) |
07b4032c GH |
860 | { |
861 | struct rq *lowest_rq = NULL; | |
07b4032c | 862 | int tries; |
4df64c0b | 863 | int cpu; |
e8fa1362 | 864 | |
07b4032c GH |
865 | for (tries = 0; tries < RT_MAX_TRIES; tries++) { |
866 | cpu = find_lowest_rq(task); | |
867 | ||
2de0b463 | 868 | if ((cpu == -1) || (cpu == rq->cpu)) |
e8fa1362 SR |
869 | break; |
870 | ||
07b4032c GH |
871 | lowest_rq = cpu_rq(cpu); |
872 | ||
e8fa1362 | 873 | /* if the prio of this runqueue changed, try again */ |
07b4032c | 874 | if (double_lock_balance(rq, lowest_rq)) { |
e8fa1362 SR |
875 | /* |
876 | * We had to unlock the run queue. In | |
877 | * the mean time, task could have | |
878 | * migrated already or had its affinity changed. | |
879 | * Also make sure that it wasn't scheduled on its rq. | |
880 | */ | |
07b4032c | 881 | if (unlikely(task_rq(task) != rq || |
4df64c0b IM |
882 | !cpu_isset(lowest_rq->cpu, |
883 | task->cpus_allowed) || | |
07b4032c | 884 | task_running(rq, task) || |
e8fa1362 | 885 | !task->se.on_rq)) { |
4df64c0b | 886 | |
e8fa1362 SR |
887 | spin_unlock(&lowest_rq->lock); |
888 | lowest_rq = NULL; | |
889 | break; | |
890 | } | |
891 | } | |
892 | ||
893 | /* If this rq is still suitable use it. */ | |
894 | if (lowest_rq->rt.highest_prio > task->prio) | |
895 | break; | |
896 | ||
897 | /* try again */ | |
898 | spin_unlock(&lowest_rq->lock); | |
899 | lowest_rq = NULL; | |
900 | } | |
901 | ||
902 | return lowest_rq; | |
903 | } | |
904 | ||
905 | /* | |
906 | * If the current CPU has more than one RT task, see if the non | |
907 | * running task can migrate over to a CPU that is running a task | |
908 | * of lesser priority. | |
909 | */ | |
697f0a48 | 910 | static int push_rt_task(struct rq *rq) |
e8fa1362 SR |
911 | { |
912 | struct task_struct *next_task; | |
913 | struct rq *lowest_rq; | |
914 | int ret = 0; | |
915 | int paranoid = RT_MAX_TRIES; | |
916 | ||
a22d7fc1 GH |
917 | if (!rq->rt.overloaded) |
918 | return 0; | |
919 | ||
697f0a48 | 920 | next_task = pick_next_highest_task_rt(rq, -1); |
e8fa1362 SR |
921 | if (!next_task) |
922 | return 0; | |
923 | ||
924 | retry: | |
697f0a48 | 925 | if (unlikely(next_task == rq->curr)) { |
f65eda4f | 926 | WARN_ON(1); |
e8fa1362 | 927 | return 0; |
f65eda4f | 928 | } |
e8fa1362 SR |
929 | |
930 | /* | |
931 | * It's possible that the next_task slipped in of | |
932 | * higher priority than current. If that's the case | |
933 | * just reschedule current. | |
934 | */ | |
697f0a48 GH |
935 | if (unlikely(next_task->prio < rq->curr->prio)) { |
936 | resched_task(rq->curr); | |
e8fa1362 SR |
937 | return 0; |
938 | } | |
939 | ||
697f0a48 | 940 | /* We might release rq lock */ |
e8fa1362 SR |
941 | get_task_struct(next_task); |
942 | ||
943 | /* find_lock_lowest_rq locks the rq if found */ | |
697f0a48 | 944 | lowest_rq = find_lock_lowest_rq(next_task, rq); |
e8fa1362 SR |
945 | if (!lowest_rq) { |
946 | struct task_struct *task; | |
947 | /* | |
697f0a48 | 948 | * find lock_lowest_rq releases rq->lock |
e8fa1362 SR |
949 | * so it is possible that next_task has changed. |
950 | * If it has, then try again. | |
951 | */ | |
697f0a48 | 952 | task = pick_next_highest_task_rt(rq, -1); |
e8fa1362 SR |
953 | if (unlikely(task != next_task) && task && paranoid--) { |
954 | put_task_struct(next_task); | |
955 | next_task = task; | |
956 | goto retry; | |
957 | } | |
958 | goto out; | |
959 | } | |
960 | ||
697f0a48 | 961 | deactivate_task(rq, next_task, 0); |
e8fa1362 SR |
962 | set_task_cpu(next_task, lowest_rq->cpu); |
963 | activate_task(lowest_rq, next_task, 0); | |
964 | ||
965 | resched_task(lowest_rq->curr); | |
966 | ||
967 | spin_unlock(&lowest_rq->lock); | |
968 | ||
969 | ret = 1; | |
970 | out: | |
971 | put_task_struct(next_task); | |
972 | ||
973 | return ret; | |
974 | } | |
975 | ||
976 | /* | |
977 | * TODO: Currently we just use the second highest prio task on | |
978 | * the queue, and stop when it can't migrate (or there's | |
979 | * no more RT tasks). There may be a case where a lower | |
980 | * priority RT task has a different affinity than the | |
981 | * higher RT task. In this case the lower RT task could | |
982 | * possibly be able to migrate where as the higher priority | |
983 | * RT task could not. We currently ignore this issue. | |
984 | * Enhancements are welcome! | |
985 | */ | |
986 | static void push_rt_tasks(struct rq *rq) | |
987 | { | |
988 | /* push_rt_task will return true if it moved an RT */ | |
989 | while (push_rt_task(rq)) | |
990 | ; | |
991 | } | |
992 | ||
f65eda4f SR |
993 | static int pull_rt_task(struct rq *this_rq) |
994 | { | |
80bf3171 IM |
995 | int this_cpu = this_rq->cpu, ret = 0, cpu; |
996 | struct task_struct *p, *next; | |
f65eda4f | 997 | struct rq *src_rq; |
f65eda4f | 998 | |
637f5085 | 999 | if (likely(!rt_overloaded(this_rq))) |
f65eda4f SR |
1000 | return 0; |
1001 | ||
1002 | next = pick_next_task_rt(this_rq); | |
1003 | ||
637f5085 | 1004 | for_each_cpu_mask(cpu, this_rq->rd->rto_mask) { |
f65eda4f SR |
1005 | if (this_cpu == cpu) |
1006 | continue; | |
1007 | ||
1008 | src_rq = cpu_rq(cpu); | |
f65eda4f SR |
1009 | /* |
1010 | * We can potentially drop this_rq's lock in | |
1011 | * double_lock_balance, and another CPU could | |
1012 | * steal our next task - hence we must cause | |
1013 | * the caller to recalculate the next task | |
1014 | * in that case: | |
1015 | */ | |
1016 | if (double_lock_balance(this_rq, src_rq)) { | |
1017 | struct task_struct *old_next = next; | |
80bf3171 | 1018 | |
f65eda4f SR |
1019 | next = pick_next_task_rt(this_rq); |
1020 | if (next != old_next) | |
1021 | ret = 1; | |
1022 | } | |
1023 | ||
1024 | /* | |
1025 | * Are there still pullable RT tasks? | |
1026 | */ | |
614ee1f6 MG |
1027 | if (src_rq->rt.rt_nr_running <= 1) |
1028 | goto skip; | |
f65eda4f | 1029 | |
f65eda4f SR |
1030 | p = pick_next_highest_task_rt(src_rq, this_cpu); |
1031 | ||
1032 | /* | |
1033 | * Do we have an RT task that preempts | |
1034 | * the to-be-scheduled task? | |
1035 | */ | |
1036 | if (p && (!next || (p->prio < next->prio))) { | |
1037 | WARN_ON(p == src_rq->curr); | |
1038 | WARN_ON(!p->se.on_rq); | |
1039 | ||
1040 | /* | |
1041 | * There's a chance that p is higher in priority | |
1042 | * than what's currently running on its cpu. | |
1043 | * This is just that p is wakeing up and hasn't | |
1044 | * had a chance to schedule. We only pull | |
1045 | * p if it is lower in priority than the | |
1046 | * current task on the run queue or | |
1047 | * this_rq next task is lower in prio than | |
1048 | * the current task on that rq. | |
1049 | */ | |
1050 | if (p->prio < src_rq->curr->prio || | |
1051 | (next && next->prio < src_rq->curr->prio)) | |
614ee1f6 | 1052 | goto skip; |
f65eda4f SR |
1053 | |
1054 | ret = 1; | |
1055 | ||
1056 | deactivate_task(src_rq, p, 0); | |
1057 | set_task_cpu(p, this_cpu); | |
1058 | activate_task(this_rq, p, 0); | |
1059 | /* | |
1060 | * We continue with the search, just in | |
1061 | * case there's an even higher prio task | |
1062 | * in another runqueue. (low likelyhood | |
1063 | * but possible) | |
80bf3171 | 1064 | * |
f65eda4f SR |
1065 | * Update next so that we won't pick a task |
1066 | * on another cpu with a priority lower (or equal) | |
1067 | * than the one we just picked. | |
1068 | */ | |
1069 | next = p; | |
1070 | ||
1071 | } | |
614ee1f6 | 1072 | skip: |
f65eda4f SR |
1073 | spin_unlock(&src_rq->lock); |
1074 | } | |
1075 | ||
1076 | return ret; | |
1077 | } | |
1078 | ||
9a897c5a | 1079 | static void pre_schedule_rt(struct rq *rq, struct task_struct *prev) |
f65eda4f SR |
1080 | { |
1081 | /* Try to pull RT tasks here if we lower this rq's prio */ | |
7f51f298 | 1082 | if (unlikely(rt_task(prev)) && rq->rt.highest_prio > prev->prio) |
f65eda4f SR |
1083 | pull_rt_task(rq); |
1084 | } | |
1085 | ||
9a897c5a | 1086 | static void post_schedule_rt(struct rq *rq) |
e8fa1362 SR |
1087 | { |
1088 | /* | |
1089 | * If we have more than one rt_task queued, then | |
1090 | * see if we can push the other rt_tasks off to other CPUS. | |
1091 | * Note we may release the rq lock, and since | |
1092 | * the lock was owned by prev, we need to release it | |
1093 | * first via finish_lock_switch and then reaquire it here. | |
1094 | */ | |
a22d7fc1 | 1095 | if (unlikely(rq->rt.overloaded)) { |
e8fa1362 SR |
1096 | spin_lock_irq(&rq->lock); |
1097 | push_rt_tasks(rq); | |
1098 | spin_unlock_irq(&rq->lock); | |
1099 | } | |
1100 | } | |
1101 | ||
8ae121ac GH |
1102 | /* |
1103 | * If we are not running and we are not going to reschedule soon, we should | |
1104 | * try to push tasks away now | |
1105 | */ | |
9a897c5a | 1106 | static void task_wake_up_rt(struct rq *rq, struct task_struct *p) |
4642dafd | 1107 | { |
9a897c5a | 1108 | if (!task_running(rq, p) && |
8ae121ac | 1109 | !test_tsk_need_resched(rq->curr) && |
a22d7fc1 | 1110 | rq->rt.overloaded) |
4642dafd SR |
1111 | push_rt_tasks(rq); |
1112 | } | |
1113 | ||
43010659 | 1114 | static unsigned long |
bb44e5d1 | 1115 | load_balance_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, |
e1d1484f PW |
1116 | unsigned long max_load_move, |
1117 | struct sched_domain *sd, enum cpu_idle_type idle, | |
1118 | int *all_pinned, int *this_best_prio) | |
bb44e5d1 | 1119 | { |
c7a1e46a SR |
1120 | /* don't touch RT tasks */ |
1121 | return 0; | |
e1d1484f PW |
1122 | } |
1123 | ||
1124 | static int | |
1125 | move_one_task_rt(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
1126 | struct sched_domain *sd, enum cpu_idle_type idle) | |
1127 | { | |
c7a1e46a SR |
1128 | /* don't touch RT tasks */ |
1129 | return 0; | |
bb44e5d1 | 1130 | } |
deeeccd4 | 1131 | |
cd8ba7cd MT |
1132 | static void set_cpus_allowed_rt(struct task_struct *p, |
1133 | const cpumask_t *new_mask) | |
73fe6aae GH |
1134 | { |
1135 | int weight = cpus_weight(*new_mask); | |
1136 | ||
1137 | BUG_ON(!rt_task(p)); | |
1138 | ||
1139 | /* | |
1140 | * Update the migration status of the RQ if we have an RT task | |
1141 | * which is running AND changing its weight value. | |
1142 | */ | |
6f505b16 | 1143 | if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) { |
73fe6aae GH |
1144 | struct rq *rq = task_rq(p); |
1145 | ||
6f505b16 | 1146 | if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) { |
73fe6aae | 1147 | rq->rt.rt_nr_migratory++; |
6f505b16 | 1148 | } else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) { |
73fe6aae GH |
1149 | BUG_ON(!rq->rt.rt_nr_migratory); |
1150 | rq->rt.rt_nr_migratory--; | |
1151 | } | |
1152 | ||
1153 | update_rt_migration(rq); | |
45c01e82 GH |
1154 | |
1155 | if (unlikely(weight == 1 || p->rt.nr_cpus_allowed == 1)) | |
1156 | /* | |
1157 | * If either the new or old weight is a "1", we need | |
1158 | * to requeue to properly move between shared and | |
1159 | * exclusive queues. | |
1160 | */ | |
1161 | requeue_task_rt(rq, p); | |
73fe6aae GH |
1162 | } |
1163 | ||
1164 | p->cpus_allowed = *new_mask; | |
6f505b16 | 1165 | p->rt.nr_cpus_allowed = weight; |
73fe6aae | 1166 | } |
deeeccd4 | 1167 | |
bdd7c81b | 1168 | /* Assumes rq->lock is held */ |
1f11eb6a | 1169 | static void rq_online_rt(struct rq *rq) |
bdd7c81b IM |
1170 | { |
1171 | if (rq->rt.overloaded) | |
1172 | rt_set_overload(rq); | |
6e0534f2 GH |
1173 | |
1174 | cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio); | |
bdd7c81b IM |
1175 | } |
1176 | ||
1177 | /* Assumes rq->lock is held */ | |
1f11eb6a | 1178 | static void rq_offline_rt(struct rq *rq) |
bdd7c81b IM |
1179 | { |
1180 | if (rq->rt.overloaded) | |
1181 | rt_clear_overload(rq); | |
6e0534f2 GH |
1182 | |
1183 | cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID); | |
bdd7c81b | 1184 | } |
cb469845 SR |
1185 | |
1186 | /* | |
1187 | * When switch from the rt queue, we bring ourselves to a position | |
1188 | * that we might want to pull RT tasks from other runqueues. | |
1189 | */ | |
1190 | static void switched_from_rt(struct rq *rq, struct task_struct *p, | |
1191 | int running) | |
1192 | { | |
1193 | /* | |
1194 | * If there are other RT tasks then we will reschedule | |
1195 | * and the scheduling of the other RT tasks will handle | |
1196 | * the balancing. But if we are the last RT task | |
1197 | * we may need to handle the pulling of RT tasks | |
1198 | * now. | |
1199 | */ | |
1200 | if (!rq->rt.rt_nr_running) | |
1201 | pull_rt_task(rq); | |
1202 | } | |
1203 | #endif /* CONFIG_SMP */ | |
1204 | ||
1205 | /* | |
1206 | * When switching a task to RT, we may overload the runqueue | |
1207 | * with RT tasks. In this case we try to push them off to | |
1208 | * other runqueues. | |
1209 | */ | |
1210 | static void switched_to_rt(struct rq *rq, struct task_struct *p, | |
1211 | int running) | |
1212 | { | |
1213 | int check_resched = 1; | |
1214 | ||
1215 | /* | |
1216 | * If we are already running, then there's nothing | |
1217 | * that needs to be done. But if we are not running | |
1218 | * we may need to preempt the current running task. | |
1219 | * If that current running task is also an RT task | |
1220 | * then see if we can move to another run queue. | |
1221 | */ | |
1222 | if (!running) { | |
1223 | #ifdef CONFIG_SMP | |
1224 | if (rq->rt.overloaded && push_rt_task(rq) && | |
1225 | /* Don't resched if we changed runqueues */ | |
1226 | rq != task_rq(p)) | |
1227 | check_resched = 0; | |
1228 | #endif /* CONFIG_SMP */ | |
1229 | if (check_resched && p->prio < rq->curr->prio) | |
1230 | resched_task(rq->curr); | |
1231 | } | |
1232 | } | |
1233 | ||
1234 | /* | |
1235 | * Priority of the task has changed. This may cause | |
1236 | * us to initiate a push or pull. | |
1237 | */ | |
1238 | static void prio_changed_rt(struct rq *rq, struct task_struct *p, | |
1239 | int oldprio, int running) | |
1240 | { | |
1241 | if (running) { | |
1242 | #ifdef CONFIG_SMP | |
1243 | /* | |
1244 | * If our priority decreases while running, we | |
1245 | * may need to pull tasks to this runqueue. | |
1246 | */ | |
1247 | if (oldprio < p->prio) | |
1248 | pull_rt_task(rq); | |
1249 | /* | |
1250 | * If there's a higher priority task waiting to run | |
6fa46fa5 SR |
1251 | * then reschedule. Note, the above pull_rt_task |
1252 | * can release the rq lock and p could migrate. | |
1253 | * Only reschedule if p is still on the same runqueue. | |
cb469845 | 1254 | */ |
6fa46fa5 | 1255 | if (p->prio > rq->rt.highest_prio && rq->curr == p) |
cb469845 SR |
1256 | resched_task(p); |
1257 | #else | |
1258 | /* For UP simply resched on drop of prio */ | |
1259 | if (oldprio < p->prio) | |
1260 | resched_task(p); | |
e8fa1362 | 1261 | #endif /* CONFIG_SMP */ |
cb469845 SR |
1262 | } else { |
1263 | /* | |
1264 | * This task is not running, but if it is | |
1265 | * greater than the current running task | |
1266 | * then reschedule. | |
1267 | */ | |
1268 | if (p->prio < rq->curr->prio) | |
1269 | resched_task(rq->curr); | |
1270 | } | |
1271 | } | |
1272 | ||
78f2c7db PZ |
1273 | static void watchdog(struct rq *rq, struct task_struct *p) |
1274 | { | |
1275 | unsigned long soft, hard; | |
1276 | ||
1277 | if (!p->signal) | |
1278 | return; | |
1279 | ||
1280 | soft = p->signal->rlim[RLIMIT_RTTIME].rlim_cur; | |
1281 | hard = p->signal->rlim[RLIMIT_RTTIME].rlim_max; | |
1282 | ||
1283 | if (soft != RLIM_INFINITY) { | |
1284 | unsigned long next; | |
1285 | ||
1286 | p->rt.timeout++; | |
1287 | next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ); | |
5a52dd50 | 1288 | if (p->rt.timeout > next) |
78f2c7db PZ |
1289 | p->it_sched_expires = p->se.sum_exec_runtime; |
1290 | } | |
1291 | } | |
bb44e5d1 | 1292 | |
8f4d37ec | 1293 | static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued) |
bb44e5d1 | 1294 | { |
67e2be02 PZ |
1295 | update_curr_rt(rq); |
1296 | ||
78f2c7db PZ |
1297 | watchdog(rq, p); |
1298 | ||
bb44e5d1 IM |
1299 | /* |
1300 | * RR tasks need a special form of timeslice management. | |
1301 | * FIFO tasks have no timeslices. | |
1302 | */ | |
1303 | if (p->policy != SCHED_RR) | |
1304 | return; | |
1305 | ||
fa717060 | 1306 | if (--p->rt.time_slice) |
bb44e5d1 IM |
1307 | return; |
1308 | ||
fa717060 | 1309 | p->rt.time_slice = DEF_TIMESLICE; |
bb44e5d1 | 1310 | |
98fbc798 DA |
1311 | /* |
1312 | * Requeue to the end of queue if we are not the only element | |
1313 | * on the queue: | |
1314 | */ | |
fa717060 | 1315 | if (p->rt.run_list.prev != p->rt.run_list.next) { |
98fbc798 DA |
1316 | requeue_task_rt(rq, p); |
1317 | set_tsk_need_resched(p); | |
1318 | } | |
bb44e5d1 IM |
1319 | } |
1320 | ||
83b699ed SV |
1321 | static void set_curr_task_rt(struct rq *rq) |
1322 | { | |
1323 | struct task_struct *p = rq->curr; | |
1324 | ||
1325 | p->se.exec_start = rq->clock; | |
1326 | } | |
1327 | ||
2abdad0a | 1328 | static const struct sched_class rt_sched_class = { |
5522d5d5 | 1329 | .next = &fair_sched_class, |
bb44e5d1 IM |
1330 | .enqueue_task = enqueue_task_rt, |
1331 | .dequeue_task = dequeue_task_rt, | |
1332 | .yield_task = yield_task_rt, | |
e7693a36 GH |
1333 | #ifdef CONFIG_SMP |
1334 | .select_task_rq = select_task_rq_rt, | |
1335 | #endif /* CONFIG_SMP */ | |
bb44e5d1 IM |
1336 | |
1337 | .check_preempt_curr = check_preempt_curr_rt, | |
1338 | ||
1339 | .pick_next_task = pick_next_task_rt, | |
1340 | .put_prev_task = put_prev_task_rt, | |
1341 | ||
681f3e68 | 1342 | #ifdef CONFIG_SMP |
bb44e5d1 | 1343 | .load_balance = load_balance_rt, |
e1d1484f | 1344 | .move_one_task = move_one_task_rt, |
73fe6aae | 1345 | .set_cpus_allowed = set_cpus_allowed_rt, |
1f11eb6a GH |
1346 | .rq_online = rq_online_rt, |
1347 | .rq_offline = rq_offline_rt, | |
9a897c5a SR |
1348 | .pre_schedule = pre_schedule_rt, |
1349 | .post_schedule = post_schedule_rt, | |
1350 | .task_wake_up = task_wake_up_rt, | |
cb469845 | 1351 | .switched_from = switched_from_rt, |
681f3e68 | 1352 | #endif |
bb44e5d1 | 1353 | |
83b699ed | 1354 | .set_curr_task = set_curr_task_rt, |
bb44e5d1 | 1355 | .task_tick = task_tick_rt, |
cb469845 SR |
1356 | |
1357 | .prio_changed = prio_changed_rt, | |
1358 | .switched_to = switched_to_rt, | |
bb44e5d1 | 1359 | }; |