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1 | /* |
1 | /* |
2 | * Copyright (C) 2001-2004 Jakub Jermar |
2 | * Copyright (C) 2001-2004 Jakub Jermar |
3 | * All rights reserved. |
3 | * All rights reserved. |
4 | * |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
7 | * are met: |
8 | * |
8 | * |
9 | * - Redistributions of source code must retain the above copyright |
9 | * - Redistributions of source code must retain the above copyright |
10 | * notice, this list of conditions and the following disclaimer. |
10 | * notice, this list of conditions and the following disclaimer. |
11 | * - Redistributions in binary form must reproduce the above copyright |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
13 | * documentation and/or other materials provided with the distribution. |
14 | * - The name of the author may not be used to endorse or promote products |
14 | * - The name of the author may not be used to endorse or promote products |
15 | * derived from this software without specific prior written permission. |
15 | * derived from this software without specific prior written permission. |
16 | * |
16 | * |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
27 | */ |
28 | 28 | ||
29 | #include <proc/scheduler.h> |
29 | #include <proc/scheduler.h> |
30 | #include <proc/thread.h> |
30 | #include <proc/thread.h> |
31 | #include <proc/task.h> |
31 | #include <proc/task.h> |
32 | #include <mm/heap.h> |
32 | #include <mm/heap.h> |
33 | #include <mm/frame.h> |
33 | #include <mm/frame.h> |
34 | #include <mm/page.h> |
34 | #include <mm/page.h> |
35 | #include <mm/as.h> |
35 | #include <mm/as.h> |
36 | #include <arch/asm.h> |
36 | #include <arch/asm.h> |
37 | #include <arch/faddr.h> |
37 | #include <arch/faddr.h> |
38 | #include <arch/atomic.h> |
38 | #include <arch/atomic.h> |
39 | #include <synch/spinlock.h> |
39 | #include <synch/spinlock.h> |
40 | #include <config.h> |
40 | #include <config.h> |
41 | #include <context.h> |
41 | #include <context.h> |
42 | #include <func.h> |
42 | #include <func.h> |
43 | #include <arch.h> |
43 | #include <arch.h> |
44 | #include <list.h> |
44 | #include <list.h> |
45 | #include <panic.h> |
45 | #include <panic.h> |
46 | #include <typedefs.h> |
46 | #include <typedefs.h> |
47 | #include <cpu.h> |
47 | #include <cpu.h> |
48 | #include <print.h> |
48 | #include <print.h> |
49 | #include <debug.h> |
49 | #include <debug.h> |
50 | 50 | ||
51 | atomic_t nrdy; |
51 | atomic_t nrdy; |
52 | 52 | ||
53 | /** Take actions before new thread runs |
53 | /** Take actions before new thread runs |
54 | * |
54 | * |
55 | * Perform actions that need to be |
55 | * Perform actions that need to be |
56 | * taken before the newly selected |
56 | * taken before the newly selected |
57 | * tread is passed control. |
57 | * tread is passed control. |
58 | * |
58 | * |
59 | */ |
59 | */ |
60 | void before_thread_runs(void) |
60 | void before_thread_runs(void) |
61 | { |
61 | { |
62 | before_thread_runs_arch(); |
62 | before_thread_runs_arch(); |
63 | #ifdef CONFIG_FPU_LAZY |
63 | #ifdef CONFIG_FPU_LAZY |
64 | if(THREAD==CPU->fpu_owner) |
64 | if(THREAD==CPU->fpu_owner) |
65 | fpu_enable(); |
65 | fpu_enable(); |
66 | else |
66 | else |
67 | fpu_disable(); |
67 | fpu_disable(); |
68 | #else |
68 | #else |
69 | fpu_enable(); |
69 | fpu_enable(); |
70 | if (THREAD->fpu_context_exists) |
70 | if (THREAD->fpu_context_exists) |
71 | fpu_context_restore(&(THREAD->saved_fpu_context)); |
71 | fpu_context_restore(&(THREAD->saved_fpu_context)); |
72 | else { |
72 | else { |
73 | fpu_init(); |
73 | fpu_init(); |
74 | THREAD->fpu_context_exists=1; |
74 | THREAD->fpu_context_exists=1; |
75 | } |
75 | } |
76 | #endif |
76 | #endif |
77 | } |
77 | } |
78 | 78 | ||
79 | #ifdef CONFIG_FPU_LAZY |
79 | #ifdef CONFIG_FPU_LAZY |
80 | void scheduler_fpu_lazy_request(void) |
80 | void scheduler_fpu_lazy_request(void) |
81 | { |
81 | { |
82 | fpu_enable(); |
82 | fpu_enable(); |
83 | if (CPU->fpu_owner != NULL) { |
83 | if (CPU->fpu_owner != NULL) { |
84 | fpu_context_save(&CPU->fpu_owner->saved_fpu_context); |
84 | fpu_context_save(&CPU->fpu_owner->saved_fpu_context); |
85 | /* don't prevent migration */ |
85 | /* don't prevent migration */ |
86 | CPU->fpu_owner->fpu_context_engaged=0; |
86 | CPU->fpu_owner->fpu_context_engaged=0; |
87 | } |
87 | } |
88 | if (THREAD->fpu_context_exists) |
88 | if (THREAD->fpu_context_exists) |
89 | fpu_context_restore(&THREAD->saved_fpu_context); |
89 | fpu_context_restore(&THREAD->saved_fpu_context); |
90 | else { |
90 | else { |
91 | fpu_init(); |
91 | fpu_init(); |
92 | THREAD->fpu_context_exists=1; |
92 | THREAD->fpu_context_exists=1; |
93 | } |
93 | } |
94 | CPU->fpu_owner=THREAD; |
94 | CPU->fpu_owner=THREAD; |
95 | THREAD->fpu_context_engaged = 1; |
95 | THREAD->fpu_context_engaged = 1; |
96 | } |
96 | } |
97 | #endif |
97 | #endif |
98 | 98 | ||
99 | /** Initialize scheduler |
99 | /** Initialize scheduler |
100 | * |
100 | * |
101 | * Initialize kernel scheduler. |
101 | * Initialize kernel scheduler. |
102 | * |
102 | * |
103 | */ |
103 | */ |
104 | void scheduler_init(void) |
104 | void scheduler_init(void) |
105 | { |
105 | { |
106 | } |
106 | } |
107 | 107 | ||
108 | 108 | ||
109 | /** Get thread to be scheduled |
109 | /** Get thread to be scheduled |
110 | * |
110 | * |
111 | * Get the optimal thread to be scheduled |
111 | * Get the optimal thread to be scheduled |
112 | * according to thread accounting and scheduler |
112 | * according to thread accounting and scheduler |
113 | * policy. |
113 | * policy. |
114 | * |
114 | * |
115 | * @return Thread to be scheduled. |
115 | * @return Thread to be scheduled. |
116 | * |
116 | * |
117 | */ |
117 | */ |
118 | static thread_t *find_best_thread(void) |
118 | static thread_t *find_best_thread(void) |
119 | { |
119 | { |
120 | thread_t *t; |
120 | thread_t *t; |
121 | runq_t *r; |
121 | runq_t *r; |
122 | int i; |
122 | int i; |
123 | 123 | ||
124 | ASSERT(CPU != NULL); |
124 | ASSERT(CPU != NULL); |
125 | 125 | ||
126 | loop: |
126 | loop: |
127 | interrupts_enable(); |
127 | interrupts_enable(); |
128 | 128 | ||
129 | if (atomic_get(&CPU->nrdy) == 0) { |
129 | if (atomic_get(&CPU->nrdy) == 0) { |
130 | /* |
130 | /* |
131 | * For there was nothing to run, the CPU goes to sleep |
131 | * For there was nothing to run, the CPU goes to sleep |
132 | * until a hardware interrupt or an IPI comes. |
132 | * until a hardware interrupt or an IPI comes. |
133 | * This improves energy saving and hyperthreading. |
133 | * This improves energy saving and hyperthreading. |
- | 134 | * |
|
- | 135 | * - we might get an interrupt here that makes some thread runnable, |
|
- | 136 | * in such a case we must wait for the next quantum to come |
|
134 | */ |
137 | */ |
135 | cpu_sleep(); |
138 | cpu_sleep(); |
136 | goto loop; |
139 | goto loop; |
137 | } |
140 | } |
138 | 141 | ||
139 | interrupts_disable(); |
142 | interrupts_disable(); |
140 | 143 | ||
141 | i = 0; |
144 | i = 0; |
142 | for (; i<RQ_COUNT; i++) { |
145 | for (; i<RQ_COUNT; i++) { |
143 | r = &CPU->rq[i]; |
146 | r = &CPU->rq[i]; |
144 | spinlock_lock(&r->lock); |
147 | spinlock_lock(&r->lock); |
145 | if (r->n == 0) { |
148 | if (r->n == 0) { |
146 | /* |
149 | /* |
147 | * If this queue is empty, try a lower-priority queue. |
150 | * If this queue is empty, try a lower-priority queue. |
148 | */ |
151 | */ |
149 | spinlock_unlock(&r->lock); |
152 | spinlock_unlock(&r->lock); |
150 | continue; |
153 | continue; |
151 | } |
154 | } |
152 | 155 | ||
153 | atomic_dec(&CPU->nrdy); |
156 | atomic_dec(&CPU->nrdy); |
154 | atomic_dec(&nrdy); |
157 | atomic_dec(&nrdy); |
155 | r->n--; |
158 | r->n--; |
156 | 159 | ||
157 | /* |
160 | /* |
158 | * Take the first thread from the queue. |
161 | * Take the first thread from the queue. |
159 | */ |
162 | */ |
160 | t = list_get_instance(r->rq_head.next, thread_t, rq_link); |
163 | t = list_get_instance(r->rq_head.next, thread_t, rq_link); |
161 | list_remove(&t->rq_link); |
164 | list_remove(&t->rq_link); |
162 | 165 | ||
163 | spinlock_unlock(&r->lock); |
166 | spinlock_unlock(&r->lock); |
164 | 167 | ||
165 | spinlock_lock(&t->lock); |
168 | spinlock_lock(&t->lock); |
166 | t->cpu = CPU; |
169 | t->cpu = CPU; |
167 | 170 | ||
168 | t->ticks = us2ticks((i+1)*10000); |
171 | t->ticks = us2ticks((i+1)*10000); |
169 | t->priority = i; /* eventually correct rq index */ |
172 | t->priority = i; /* eventually correct rq index */ |
170 | 173 | ||
171 | /* |
174 | /* |
172 | * Clear the X_STOLEN flag so that t can be migrated when load balancing needs emerge. |
175 | * Clear the X_STOLEN flag so that t can be migrated when load balancing needs emerge. |
173 | */ |
176 | */ |
174 | t->flags &= ~X_STOLEN; |
177 | t->flags &= ~X_STOLEN; |
175 | spinlock_unlock(&t->lock); |
178 | spinlock_unlock(&t->lock); |
176 | 179 | ||
177 | return t; |
180 | return t; |
178 | } |
181 | } |
179 | goto loop; |
182 | goto loop; |
180 | 183 | ||
181 | } |
184 | } |
182 | 185 | ||
183 | 186 | ||
184 | /** Prevent rq starvation |
187 | /** Prevent rq starvation |
185 | * |
188 | * |
186 | * Prevent low priority threads from starving in rq's. |
189 | * Prevent low priority threads from starving in rq's. |
187 | * |
190 | * |
188 | * When the function decides to relink rq's, it reconnects |
191 | * When the function decides to relink rq's, it reconnects |
189 | * respective pointers so that in result threads with 'pri' |
192 | * respective pointers so that in result threads with 'pri' |
190 | * greater or equal 'start' are moved to a higher-priority queue. |
193 | * greater or equal 'start' are moved to a higher-priority queue. |
191 | * |
194 | * |
192 | * @param start Threshold priority. |
195 | * @param start Threshold priority. |
193 | * |
196 | * |
194 | */ |
197 | */ |
195 | static void relink_rq(int start) |
198 | static void relink_rq(int start) |
196 | { |
199 | { |
197 | link_t head; |
200 | link_t head; |
198 | runq_t *r; |
201 | runq_t *r; |
199 | int i, n; |
202 | int i, n; |
200 | 203 | ||
201 | list_initialize(&head); |
204 | list_initialize(&head); |
202 | spinlock_lock(&CPU->lock); |
205 | spinlock_lock(&CPU->lock); |
203 | if (CPU->needs_relink > NEEDS_RELINK_MAX) { |
206 | if (CPU->needs_relink > NEEDS_RELINK_MAX) { |
204 | for (i = start; i<RQ_COUNT-1; i++) { |
207 | for (i = start; i<RQ_COUNT-1; i++) { |
205 | /* remember and empty rq[i + 1] */ |
208 | /* remember and empty rq[i + 1] */ |
206 | r = &CPU->rq[i + 1]; |
209 | r = &CPU->rq[i + 1]; |
207 | spinlock_lock(&r->lock); |
210 | spinlock_lock(&r->lock); |
208 | list_concat(&head, &r->rq_head); |
211 | list_concat(&head, &r->rq_head); |
209 | n = r->n; |
212 | n = r->n; |
210 | r->n = 0; |
213 | r->n = 0; |
211 | spinlock_unlock(&r->lock); |
214 | spinlock_unlock(&r->lock); |
212 | 215 | ||
213 | /* append rq[i + 1] to rq[i] */ |
216 | /* append rq[i + 1] to rq[i] */ |
214 | r = &CPU->rq[i]; |
217 | r = &CPU->rq[i]; |
215 | spinlock_lock(&r->lock); |
218 | spinlock_lock(&r->lock); |
216 | list_concat(&r->rq_head, &head); |
219 | list_concat(&r->rq_head, &head); |
217 | r->n += n; |
220 | r->n += n; |
218 | spinlock_unlock(&r->lock); |
221 | spinlock_unlock(&r->lock); |
219 | } |
222 | } |
220 | CPU->needs_relink = 0; |
223 | CPU->needs_relink = 0; |
221 | } |
224 | } |
222 | spinlock_unlock(&CPU->lock); |
225 | spinlock_unlock(&CPU->lock); |
223 | 226 | ||
224 | } |
227 | } |
225 | 228 | ||
226 | 229 | ||
227 | /** Scheduler stack switch wrapper |
230 | /** Scheduler stack switch wrapper |
228 | * |
231 | * |
229 | * Second part of the scheduler() function |
232 | * Second part of the scheduler() function |
230 | * using new stack. Handling the actual context |
233 | * using new stack. Handling the actual context |
231 | * switch to a new thread. |
234 | * switch to a new thread. |
232 | * |
235 | * |
233 | */ |
236 | */ |
234 | static void scheduler_separated_stack(void) |
237 | static void scheduler_separated_stack(void) |
235 | { |
238 | { |
236 | int priority; |
239 | int priority; |
237 | 240 | ||
238 | ASSERT(CPU != NULL); |
241 | ASSERT(CPU != NULL); |
239 | 242 | ||
240 | if (THREAD) { |
243 | if (THREAD) { |
241 | switch (THREAD->state) { |
244 | switch (THREAD->state) { |
242 | case Running: |
245 | case Running: |
243 | THREAD->state = Ready; |
246 | THREAD->state = Ready; |
244 | spinlock_unlock(&THREAD->lock); |
247 | spinlock_unlock(&THREAD->lock); |
245 | thread_ready(THREAD); |
248 | thread_ready(THREAD); |
246 | break; |
249 | break; |
247 | 250 | ||
248 | case Exiting: |
251 | case Exiting: |
249 | frame_free((__address) THREAD->kstack); |
252 | frame_free((__address) THREAD->kstack); |
250 | if (THREAD->ustack) { |
253 | if (THREAD->ustack) { |
251 | frame_free((__address) THREAD->ustack); |
254 | frame_free((__address) THREAD->ustack); |
252 | } |
255 | } |
253 | 256 | ||
254 | /* |
257 | /* |
255 | * Detach from the containing task. |
258 | * Detach from the containing task. |
256 | */ |
259 | */ |
257 | spinlock_lock(&TASK->lock); |
260 | spinlock_lock(&TASK->lock); |
258 | list_remove(&THREAD->th_link); |
261 | list_remove(&THREAD->th_link); |
259 | spinlock_unlock(&TASK->lock); |
262 | spinlock_unlock(&TASK->lock); |
260 | 263 | ||
261 | spinlock_unlock(&THREAD->lock); |
264 | spinlock_unlock(&THREAD->lock); |
262 | 265 | ||
263 | spinlock_lock(&threads_lock); |
266 | spinlock_lock(&threads_lock); |
264 | list_remove(&THREAD->threads_link); |
267 | list_remove(&THREAD->threads_link); |
265 | spinlock_unlock(&threads_lock); |
268 | spinlock_unlock(&threads_lock); |
266 | 269 | ||
267 | spinlock_lock(&CPU->lock); |
270 | spinlock_lock(&CPU->lock); |
268 | if(CPU->fpu_owner==THREAD) |
271 | if(CPU->fpu_owner==THREAD) |
269 | CPU->fpu_owner=NULL; |
272 | CPU->fpu_owner=NULL; |
270 | spinlock_unlock(&CPU->lock); |
273 | spinlock_unlock(&CPU->lock); |
271 | 274 | ||
272 | free(THREAD); |
275 | free(THREAD); |
273 | 276 | ||
274 | break; |
277 | break; |
275 | 278 | ||
276 | case Sleeping: |
279 | case Sleeping: |
277 | /* |
280 | /* |
278 | * Prefer the thread after it's woken up. |
281 | * Prefer the thread after it's woken up. |
279 | */ |
282 | */ |
280 | THREAD->priority = -1; |
283 | THREAD->priority = -1; |
281 | 284 | ||
282 | /* |
285 | /* |
283 | * We need to release wq->lock which we locked in waitq_sleep(). |
286 | * We need to release wq->lock which we locked in waitq_sleep(). |
284 | * Address of wq->lock is kept in THREAD->sleep_queue. |
287 | * Address of wq->lock is kept in THREAD->sleep_queue. |
285 | */ |
288 | */ |
286 | spinlock_unlock(&THREAD->sleep_queue->lock); |
289 | spinlock_unlock(&THREAD->sleep_queue->lock); |
287 | 290 | ||
288 | /* |
291 | /* |
289 | * Check for possible requests for out-of-context invocation. |
292 | * Check for possible requests for out-of-context invocation. |
290 | */ |
293 | */ |
291 | if (THREAD->call_me) { |
294 | if (THREAD->call_me) { |
292 | THREAD->call_me(THREAD->call_me_with); |
295 | THREAD->call_me(THREAD->call_me_with); |
293 | THREAD->call_me = NULL; |
296 | THREAD->call_me = NULL; |
294 | THREAD->call_me_with = NULL; |
297 | THREAD->call_me_with = NULL; |
295 | } |
298 | } |
296 | 299 | ||
297 | spinlock_unlock(&THREAD->lock); |
300 | spinlock_unlock(&THREAD->lock); |
298 | 301 | ||
299 | break; |
302 | break; |
300 | 303 | ||
301 | default: |
304 | default: |
302 | /* |
305 | /* |
303 | * Entering state is unexpected. |
306 | * Entering state is unexpected. |
304 | */ |
307 | */ |
305 | panic("tid%d: unexpected state %s\n", THREAD->tid, thread_states[THREAD->state]); |
308 | panic("tid%d: unexpected state %s\n", THREAD->tid, thread_states[THREAD->state]); |
306 | break; |
309 | break; |
307 | } |
310 | } |
308 | THREAD = NULL; |
311 | THREAD = NULL; |
309 | } |
312 | } |
310 | 313 | ||
311 | 314 | ||
312 | THREAD = find_best_thread(); |
315 | THREAD = find_best_thread(); |
313 | 316 | ||
314 | spinlock_lock(&THREAD->lock); |
317 | spinlock_lock(&THREAD->lock); |
315 | priority = THREAD->priority; |
318 | priority = THREAD->priority; |
316 | spinlock_unlock(&THREAD->lock); |
319 | spinlock_unlock(&THREAD->lock); |
317 | 320 | ||
318 | relink_rq(priority); |
321 | relink_rq(priority); |
319 | 322 | ||
320 | spinlock_lock(&THREAD->lock); |
323 | spinlock_lock(&THREAD->lock); |
321 | 324 | ||
322 | /* |
325 | /* |
323 | * If both the old and the new task are the same, lots of work is avoided. |
326 | * If both the old and the new task are the same, lots of work is avoided. |
324 | */ |
327 | */ |
325 | if (TASK != THREAD->task) { |
328 | if (TASK != THREAD->task) { |
326 | as_t *as1 = NULL; |
329 | as_t *as1 = NULL; |
327 | as_t *as2; |
330 | as_t *as2; |
328 | 331 | ||
329 | if (TASK) { |
332 | if (TASK) { |
330 | spinlock_lock(&TASK->lock); |
333 | spinlock_lock(&TASK->lock); |
331 | as1 = TASK->as; |
334 | as1 = TASK->as; |
332 | spinlock_unlock(&TASK->lock); |
335 | spinlock_unlock(&TASK->lock); |
333 | } |
336 | } |
334 | 337 | ||
335 | spinlock_lock(&THREAD->task->lock); |
338 | spinlock_lock(&THREAD->task->lock); |
336 | as2 = THREAD->task->as; |
339 | as2 = THREAD->task->as; |
337 | spinlock_unlock(&THREAD->task->lock); |
340 | spinlock_unlock(&THREAD->task->lock); |
338 | 341 | ||
339 | /* |
342 | /* |
340 | * Note that it is possible for two tasks to share one address space. |
343 | * Note that it is possible for two tasks to share one address space. |
341 | */ |
344 | */ |
342 | if (as1 != as2) { |
345 | if (as1 != as2) { |
343 | /* |
346 | /* |
344 | * Both tasks and address spaces are different. |
347 | * Both tasks and address spaces are different. |
345 | * Replace the old one with the new one. |
348 | * Replace the old one with the new one. |
346 | */ |
349 | */ |
347 | as_install(as2); |
350 | as_install(as2); |
348 | } |
351 | } |
349 | TASK = THREAD->task; |
352 | TASK = THREAD->task; |
350 | } |
353 | } |
351 | 354 | ||
352 | THREAD->state = Running; |
355 | THREAD->state = Running; |
353 | 356 | ||
354 | #ifdef SCHEDULER_VERBOSE |
357 | #ifdef SCHEDULER_VERBOSE |
355 | printf("cpu%d: tid %d (priority=%d,ticks=%d,nrdy=%d)\n", CPU->id, THREAD->tid, THREAD->priority, THREAD->ticks, CPU->nrdy); |
358 | printf("cpu%d: tid %d (priority=%d,ticks=%d,nrdy=%d)\n", CPU->id, THREAD->tid, THREAD->priority, THREAD->ticks, CPU->nrdy); |
356 | #endif |
359 | #endif |
357 | 360 | ||
358 | /* |
361 | /* |
359 | * Copy the knowledge of CPU, TASK, THREAD and preemption counter to thread's stack. |
362 | * Copy the knowledge of CPU, TASK, THREAD and preemption counter to thread's stack. |
360 | */ |
363 | */ |
361 | the_copy(THE, (the_t *) THREAD->kstack); |
364 | the_copy(THE, (the_t *) THREAD->kstack); |
362 | 365 | ||
363 | context_restore(&THREAD->saved_context); |
366 | context_restore(&THREAD->saved_context); |
364 | /* not reached */ |
367 | /* not reached */ |
365 | } |
368 | } |
366 | 369 | ||
367 | 370 | ||
368 | /** The scheduler |
371 | /** The scheduler |
369 | * |
372 | * |
370 | * The thread scheduling procedure. |
373 | * The thread scheduling procedure. |
371 | * Passes control directly to |
374 | * Passes control directly to |
372 | * scheduler_separated_stack(). |
375 | * scheduler_separated_stack(). |
373 | * |
376 | * |
374 | */ |
377 | */ |
375 | void scheduler(void) |
378 | void scheduler(void) |
376 | { |
379 | { |
377 | volatile ipl_t ipl; |
380 | volatile ipl_t ipl; |
378 | 381 | ||
379 | ASSERT(CPU != NULL); |
382 | ASSERT(CPU != NULL); |
380 | 383 | ||
381 | ipl = interrupts_disable(); |
384 | ipl = interrupts_disable(); |
382 | 385 | ||
383 | if (atomic_get(&haltstate)) |
386 | if (atomic_get(&haltstate)) |
384 | halt(); |
387 | halt(); |
385 | 388 | ||
386 | if (THREAD) { |
389 | if (THREAD) { |
387 | spinlock_lock(&THREAD->lock); |
390 | spinlock_lock(&THREAD->lock); |
388 | #ifndef CONFIG_FPU_LAZY |
391 | #ifndef CONFIG_FPU_LAZY |
389 | fpu_context_save(&(THREAD->saved_fpu_context)); |
392 | fpu_context_save(&(THREAD->saved_fpu_context)); |
390 | #endif |
393 | #endif |
391 | if (!context_save(&THREAD->saved_context)) { |
394 | if (!context_save(&THREAD->saved_context)) { |
392 | /* |
395 | /* |
393 | * This is the place where threads leave scheduler(); |
396 | * This is the place where threads leave scheduler(); |
394 | */ |
397 | */ |
395 | before_thread_runs(); |
398 | before_thread_runs(); |
396 | spinlock_unlock(&THREAD->lock); |
399 | spinlock_unlock(&THREAD->lock); |
397 | interrupts_restore(THREAD->saved_context.ipl); |
400 | interrupts_restore(THREAD->saved_context.ipl); |
398 | return; |
401 | return; |
399 | } |
402 | } |
400 | 403 | ||
401 | /* |
404 | /* |
402 | * Interrupt priority level of preempted thread is recorded here |
405 | * Interrupt priority level of preempted thread is recorded here |
403 | * to facilitate scheduler() invocations from interrupts_disable()'d |
406 | * to facilitate scheduler() invocations from interrupts_disable()'d |
404 | * code (e.g. waitq_sleep_timeout()). |
407 | * code (e.g. waitq_sleep_timeout()). |
405 | */ |
408 | */ |
406 | THREAD->saved_context.ipl = ipl; |
409 | THREAD->saved_context.ipl = ipl; |
407 | } |
410 | } |
408 | 411 | ||
409 | /* |
412 | /* |
410 | * Through the 'THE' structure, we keep track of THREAD, TASK, CPU, VM |
413 | * Through the 'THE' structure, we keep track of THREAD, TASK, CPU, VM |
411 | * and preemption counter. At this point THE could be coming either |
414 | * and preemption counter. At this point THE could be coming either |
412 | * from THREAD's or CPU's stack. |
415 | * from THREAD's or CPU's stack. |
413 | */ |
416 | */ |
414 | the_copy(THE, (the_t *) CPU->stack); |
417 | the_copy(THE, (the_t *) CPU->stack); |
415 | 418 | ||
416 | /* |
419 | /* |
417 | * We may not keep the old stack. |
420 | * We may not keep the old stack. |
418 | * Reason: If we kept the old stack and got blocked, for instance, in |
421 | * Reason: If we kept the old stack and got blocked, for instance, in |
419 | * find_best_thread(), the old thread could get rescheduled by another |
422 | * find_best_thread(), the old thread could get rescheduled by another |
420 | * CPU and overwrite the part of its own stack that was also used by |
423 | * CPU and overwrite the part of its own stack that was also used by |
421 | * the scheduler on this CPU. |
424 | * the scheduler on this CPU. |
422 | * |
425 | * |
423 | * Moreover, we have to bypass the compiler-generated POP sequence |
426 | * Moreover, we have to bypass the compiler-generated POP sequence |
424 | * which is fooled by SP being set to the very top of the stack. |
427 | * which is fooled by SP being set to the very top of the stack. |
425 | * Therefore the scheduler() function continues in |
428 | * Therefore the scheduler() function continues in |
426 | * scheduler_separated_stack(). |
429 | * scheduler_separated_stack(). |
427 | */ |
430 | */ |
428 | context_save(&CPU->saved_context); |
431 | context_save(&CPU->saved_context); |
429 | context_set(&CPU->saved_context, FADDR(scheduler_separated_stack), (__address) CPU->stack, CPU_STACK_SIZE); |
432 | context_set(&CPU->saved_context, FADDR(scheduler_separated_stack), (__address) CPU->stack, CPU_STACK_SIZE); |
430 | context_restore(&CPU->saved_context); |
433 | context_restore(&CPU->saved_context); |
431 | /* not reached */ |
434 | /* not reached */ |
432 | } |
435 | } |
433 | 436 | ||
434 | 437 | ||
435 | 438 | ||
436 | 439 | ||
437 | 440 | ||
438 | #ifdef CONFIG_SMP |
441 | #ifdef CONFIG_SMP |
439 | /** Load balancing thread |
442 | /** Load balancing thread |
440 | * |
443 | * |
441 | * SMP load balancing thread, supervising thread supplies |
444 | * SMP load balancing thread, supervising thread supplies |
442 | * for the CPU it's wired to. |
445 | * for the CPU it's wired to. |
443 | * |
446 | * |
444 | * @param arg Generic thread argument (unused). |
447 | * @param arg Generic thread argument (unused). |
445 | * |
448 | * |
446 | */ |
449 | */ |
447 | void kcpulb(void *arg) |
450 | void kcpulb(void *arg) |
448 | { |
451 | { |
449 | thread_t *t; |
452 | thread_t *t; |
450 | int count, average, i, j, k = 0; |
453 | int count, average, i, j, k = 0; |
451 | ipl_t ipl; |
454 | ipl_t ipl; |
452 | 455 | ||
453 | loop: |
456 | loop: |
454 | /* |
457 | /* |
455 | * Work in 1s intervals. |
458 | * Work in 1s intervals. |
456 | */ |
459 | */ |
457 | thread_sleep(1); |
460 | thread_sleep(1); |
458 | 461 | ||
459 | not_satisfied: |
462 | not_satisfied: |
460 | /* |
463 | /* |
461 | * Calculate the number of threads that will be migrated/stolen from |
464 | * Calculate the number of threads that will be migrated/stolen from |
462 | * other CPU's. Note that situation can have changed between two |
465 | * other CPU's. Note that situation can have changed between two |
463 | * passes. Each time get the most up to date counts. |
466 | * passes. Each time get the most up to date counts. |
464 | */ |
467 | */ |
465 | average = atomic_get(&nrdy) / config.cpu_active; |
468 | average = atomic_get(&nrdy) / config.cpu_active + 1; |
466 | count = average - atomic_get(&CPU->nrdy); |
469 | count = average - atomic_get(&CPU->nrdy); |
467 | 470 | ||
468 | if (count < 0) |
471 | if (count <= 0) |
469 | goto satisfied; |
472 | goto satisfied; |
470 | 473 | ||
471 | if (!count) { /* Try to steal threads from CPU's that have more then average count */ |
- | |
472 | count = 1; |
- | |
473 | average += 1; |
- | |
474 | } |
- | |
475 | - | ||
476 | /* |
474 | /* |
477 | * Searching least priority queues on all CPU's first and most priority queues on all CPU's last. |
475 | * Searching least priority queues on all CPU's first and most priority queues on all CPU's last. |
478 | */ |
476 | */ |
479 | for (j=RQ_COUNT-1; j >= 0; j--) { |
477 | for (j=RQ_COUNT-1; j >= 0; j--) { |
480 | for (i=0; i < config.cpu_active; i++) { |
478 | for (i=0; i < config.cpu_active; i++) { |
481 | link_t *l; |
479 | link_t *l; |
482 | runq_t *r; |
480 | runq_t *r; |
483 | cpu_t *cpu; |
481 | cpu_t *cpu; |
484 | 482 | ||
485 | cpu = &cpus[(i + k) % config.cpu_active]; |
483 | cpu = &cpus[(i + k) % config.cpu_active]; |
486 | 484 | ||
487 | /* |
485 | /* |
488 | * Not interested in ourselves. |
486 | * Not interested in ourselves. |
489 | * Doesn't require interrupt disabling for kcpulb is X_WIRED. |
487 | * Doesn't require interrupt disabling for kcpulb is X_WIRED. |
490 | */ |
488 | */ |
491 | if (CPU == cpu) |
489 | if (CPU == cpu) |
492 | continue; |
490 | continue; |
493 | if (atomic_get(&cpu->nrdy) <= average) |
491 | if (atomic_get(&cpu->nrdy) <= average) |
494 | continue; |
492 | continue; |
495 | 493 | ||
496 | restart: ipl = interrupts_disable(); |
494 | ipl = interrupts_disable(); |
497 | r = &cpu->rq[j]; |
495 | r = &cpu->rq[j]; |
498 | spinlock_lock(&r->lock); |
496 | spinlock_lock(&r->lock); |
499 | if (r->n == 0) { |
497 | if (r->n == 0) { |
500 | spinlock_unlock(&r->lock); |
498 | spinlock_unlock(&r->lock); |
501 | interrupts_restore(ipl); |
499 | interrupts_restore(ipl); |
502 | continue; |
500 | continue; |
503 | } |
501 | } |
504 | 502 | ||
505 | t = NULL; |
503 | t = NULL; |
506 | l = r->rq_head.prev; /* search rq from the back */ |
504 | l = r->rq_head.prev; /* search rq from the back */ |
507 | while (l != &r->rq_head) { |
505 | while (l != &r->rq_head) { |
508 | t = list_get_instance(l, thread_t, rq_link); |
506 | t = list_get_instance(l, thread_t, rq_link); |
509 | /* |
507 | /* |
510 | * We don't want to steal CPU-wired threads neither threads already stolen. |
508 | * We don't want to steal CPU-wired threads neither threads already stolen. |
511 | * The latter prevents threads from migrating between CPU's without ever being run. |
509 | * The latter prevents threads from migrating between CPU's without ever being run. |
512 | * We don't want to steal threads whose FPU context is still in CPU. |
510 | * We don't want to steal threads whose FPU context is still in CPU. |
513 | */ |
511 | */ |
514 | spinlock_lock(&t->lock); |
512 | spinlock_lock(&t->lock); |
515 | if ( (!(t->flags & (X_WIRED | X_STOLEN))) && (!(t->fpu_context_engaged)) ) { |
513 | if ( (!(t->flags & (X_WIRED | X_STOLEN))) && (!(t->fpu_context_engaged)) ) { |
516 | - | ||
517 | /* |
514 | /* |
518 | * Remove t from r. |
515 | * Remove t from r. |
519 | */ |
516 | */ |
520 | - | ||
521 | spinlock_unlock(&t->lock); |
517 | spinlock_unlock(&t->lock); |
522 | 518 | ||
523 | /* |
- | |
524 | * Here we have to avoid deadlock with relink_rq(), |
- | |
525 | * because it locks cpu and r in a different order than we do. |
- | |
526 | */ |
- | |
527 | if (!spinlock_trylock(&cpu->lock)) { |
- | |
528 | /* Release all locks and try again. */ |
- | |
529 | spinlock_unlock(&r->lock); |
- | |
530 | interrupts_restore(ipl); |
- | |
531 | goto restart; |
- | |
532 | } |
- | |
533 | atomic_dec(&cpu->nrdy); |
519 | atomic_dec(&cpu->nrdy); |
534 | spinlock_unlock(&cpu->lock); |
- | |
535 | - | ||
536 | atomic_dec(&nrdy); |
520 | atomic_dec(&nrdy); |
537 | 521 | ||
538 | r->n--; |
522 | r->n--; |
539 | list_remove(&t->rq_link); |
523 | list_remove(&t->rq_link); |
540 | 524 | ||
541 | break; |
525 | break; |
542 | } |
526 | } |
543 | spinlock_unlock(&t->lock); |
527 | spinlock_unlock(&t->lock); |
544 | l = l->prev; |
528 | l = l->prev; |
545 | t = NULL; |
529 | t = NULL; |
546 | } |
530 | } |
547 | spinlock_unlock(&r->lock); |
531 | spinlock_unlock(&r->lock); |
548 | 532 | ||
549 | if (t) { |
533 | if (t) { |
550 | /* |
534 | /* |
551 | * Ready t on local CPU |
535 | * Ready t on local CPU |
552 | */ |
536 | */ |
553 | spinlock_lock(&t->lock); |
537 | spinlock_lock(&t->lock); |
554 | #ifdef KCPULB_VERBOSE |
538 | #ifdef KCPULB_VERBOSE |
555 | printf("kcpulb%d: TID %d -> cpu%d, nrdy=%d, avg=%d\n", CPU->id, t->tid, CPU->id, atomic_get(&CPU->nrdy), atomic_get(&nrdy) / config.cpu_active); |
539 | printf("kcpulb%d: TID %d -> cpu%d, nrdy=%d, avg=%d\n", CPU->id, t->tid, CPU->id, atomic_get(&CPU->nrdy), atomic_get(&nrdy) / config.cpu_active); |
556 | #endif |
540 | #endif |
557 | t->flags |= X_STOLEN; |
541 | t->flags |= X_STOLEN; |
558 | spinlock_unlock(&t->lock); |
542 | spinlock_unlock(&t->lock); |
559 | 543 | ||
560 | thread_ready(t); |
544 | thread_ready(t); |
561 | 545 | ||
562 | interrupts_restore(ipl); |
546 | interrupts_restore(ipl); |
563 | 547 | ||
564 | if (--count == 0) |
548 | if (--count == 0) |
565 | goto satisfied; |
549 | goto satisfied; |
566 | 550 | ||
567 | /* |
551 | /* |
568 | * We are not satisfied yet, focus on another CPU next time. |
552 | * We are not satisfied yet, focus on another CPU next time. |
569 | */ |
553 | */ |
570 | k++; |
554 | k++; |
571 | 555 | ||
572 | continue; |
556 | continue; |
573 | } |
557 | } |
574 | interrupts_restore(ipl); |
558 | interrupts_restore(ipl); |
575 | } |
559 | } |
576 | } |
560 | } |
577 | 561 | ||
578 | if (atomic_get(&CPU->nrdy)) { |
562 | if (atomic_get(&CPU->nrdy)) { |
579 | /* |
563 | /* |
580 | * Be a little bit light-weight and let migrated threads run. |
564 | * Be a little bit light-weight and let migrated threads run. |
581 | */ |
565 | */ |
582 | scheduler(); |
566 | scheduler(); |
583 | } else { |
567 | } else { |
584 | /* |
568 | /* |
585 | * We failed to migrate a single thread. |
569 | * We failed to migrate a single thread. |
586 | * Give up this turn. |
570 | * Give up this turn. |
587 | */ |
571 | */ |
588 | goto loop; |
572 | goto loop; |
589 | } |
573 | } |
590 | 574 | ||
591 | goto not_satisfied; |
575 | goto not_satisfied; |
592 | 576 | ||
593 | satisfied: |
577 | satisfied: |
594 | goto loop; |
578 | goto loop; |
595 | } |
579 | } |
596 | 580 | ||
597 | #endif /* CONFIG_SMP */ |
581 | #endif /* CONFIG_SMP */ |
598 | 582 | ||
599 | 583 | ||
600 | /** Print information about threads & scheduler queues */ |
584 | /** Print information about threads & scheduler queues */ |
601 | void sched_print_list(void) |
585 | void sched_print_list(void) |
602 | { |
586 | { |
603 | ipl_t ipl; |
587 | ipl_t ipl; |
604 | int cpu,i; |
588 | int cpu,i; |
605 | runq_t *r; |
589 | runq_t *r; |
606 | thread_t *t; |
590 | thread_t *t; |
607 | link_t *cur; |
591 | link_t *cur; |
608 | 592 | ||
609 | /* We are going to mess with scheduler structures, |
593 | /* We are going to mess with scheduler structures, |
610 | * let's not be interrupted */ |
594 | * let's not be interrupted */ |
611 | ipl = interrupts_disable(); |
595 | ipl = interrupts_disable(); |
612 | printf("*********** Scheduler dump ***********\n"); |
596 | printf("*********** Scheduler dump ***********\n"); |
613 | for (cpu=0;cpu < config.cpu_count; cpu++) { |
597 | for (cpu=0;cpu < config.cpu_count; cpu++) { |
614 | if (!cpus[cpu].active) |
598 | if (!cpus[cpu].active) |
615 | continue; |
599 | continue; |
616 | spinlock_lock(&cpus[cpu].lock); |
600 | spinlock_lock(&cpus[cpu].lock); |
617 | printf("cpu%d: nrdy: %d needs_relink: %d\n", |
601 | printf("cpu%d: nrdy: %d needs_relink: %d\n", |
618 | cpus[cpu].id, atomic_get(&cpus[cpu].nrdy), cpus[cpu].needs_relink); |
602 | cpus[cpu].id, atomic_get(&cpus[cpu].nrdy), cpus[cpu].needs_relink); |
619 | 603 | ||
620 | for (i=0; i<RQ_COUNT; i++) { |
604 | for (i=0; i<RQ_COUNT; i++) { |
621 | r = &cpus[cpu].rq[i]; |
605 | r = &cpus[cpu].rq[i]; |
622 | spinlock_lock(&r->lock); |
606 | spinlock_lock(&r->lock); |
623 | if (!r->n) { |
607 | if (!r->n) { |
624 | spinlock_unlock(&r->lock); |
608 | spinlock_unlock(&r->lock); |
625 | continue; |
609 | continue; |
626 | } |
610 | } |
627 | printf("\tRq %d: ", i); |
611 | printf("\tRq %d: ", i); |
628 | for (cur=r->rq_head.next; cur!=&r->rq_head; cur=cur->next) { |
612 | for (cur=r->rq_head.next; cur!=&r->rq_head; cur=cur->next) { |
629 | t = list_get_instance(cur, thread_t, rq_link); |
613 | t = list_get_instance(cur, thread_t, rq_link); |
630 | printf("%d(%s) ", t->tid, |
614 | printf("%d(%s) ", t->tid, |
631 | thread_states[t->state]); |
615 | thread_states[t->state]); |
632 | } |
616 | } |
633 | printf("\n"); |
617 | printf("\n"); |
634 | spinlock_unlock(&r->lock); |
618 | spinlock_unlock(&r->lock); |
635 | } |
619 | } |
636 | spinlock_unlock(&cpus[cpu].lock); |
620 | spinlock_unlock(&cpus[cpu].lock); |
637 | } |
621 | } |
638 | 622 | ||
639 | interrupts_restore(ipl); |
623 | interrupts_restore(ipl); |
640 | } |
624 | } |
641 | 625 |