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authorGlenn Elliott <gelliott@cs.unc.edu>2012-05-26 17:29:58 -0400
committerGlenn Elliott <gelliott@cs.unc.edu>2012-05-26 17:29:58 -0400
commita463f9a9e04385f0729f7435a0a6dff7d89b25de (patch)
tree00ff42c305926c800e18b13df8440a4de1a1a041 /litmus/litmus_softirq.c
parent6a00f206debf8a5c8899055726ad127dbeeed098 (diff)
GPUSync patch for Litmus 2012.1.
Diffstat (limited to 'litmus/litmus_softirq.c')
-rw-r--r--litmus/litmus_softirq.c1582
1 files changed, 1582 insertions, 0 deletions
diff --git a/litmus/litmus_softirq.c b/litmus/litmus_softirq.c
new file mode 100644
index 000000000000..9f7d9da5facb
--- /dev/null
+++ b/litmus/litmus_softirq.c
@@ -0,0 +1,1582 @@
1#include <linux/interrupt.h>
2#include <linux/percpu.h>
3#include <linux/cpu.h>
4#include <linux/kthread.h>
5#include <linux/ftrace.h>
6#include <linux/smp.h>
7#include <linux/slab.h>
8#include <linux/mutex.h>
9
10#include <linux/sched.h>
11#include <linux/cpuset.h>
12
13#include <litmus/litmus.h>
14#include <litmus/sched_trace.h>
15#include <litmus/jobs.h>
16#include <litmus/sched_plugin.h>
17#include <litmus/litmus_softirq.h>
18
19/* TODO: Remove unneeded mb() and other barriers. */
20
21
22/* counts number of daemons ready to handle litmus irqs. */
23static atomic_t num_ready_klitirqds = ATOMIC_INIT(0);
24
25enum pending_flags
26{
27 LIT_TASKLET_LOW = 0x1,
28 LIT_TASKLET_HI = LIT_TASKLET_LOW<<1,
29 LIT_WORK = LIT_TASKLET_HI<<1
30};
31
32/* only support tasklet processing for now. */
33struct tasklet_head
34{
35 struct tasklet_struct *head;
36 struct tasklet_struct **tail;
37};
38
39struct klitirqd_info
40{
41 struct task_struct* klitirqd;
42 struct task_struct* current_owner;
43 int terminating;
44
45
46 raw_spinlock_t lock;
47
48 u32 pending;
49 atomic_t num_hi_pending;
50 atomic_t num_low_pending;
51 atomic_t num_work_pending;
52
53 /* in order of priority */
54 struct tasklet_head pending_tasklets_hi;
55 struct tasklet_head pending_tasklets;
56 struct list_head worklist;
57};
58
59/* one list for each klitirqd */
60static struct klitirqd_info klitirqds[NR_LITMUS_SOFTIRQD];
61
62
63
64
65
66int proc_read_klitirqd_stats(char *page, char **start,
67 off_t off, int count,
68 int *eof, void *data)
69{
70 int len = snprintf(page, PAGE_SIZE,
71 "num ready klitirqds: %d\n\n",
72 atomic_read(&num_ready_klitirqds));
73
74 if(klitirqd_is_ready())
75 {
76 int i;
77 for(i = 0; i < NR_LITMUS_SOFTIRQD; ++i)
78 {
79 len +=
80 snprintf(page + len - 1, PAGE_SIZE, /* -1 to strip off \0 */
81 "klitirqd_th%d: %s/%d\n"
82 "\tcurrent_owner: %s/%d\n"
83 "\tpending: %x\n"
84 "\tnum hi: %d\n"
85 "\tnum low: %d\n"
86 "\tnum work: %d\n\n",
87 i,
88 klitirqds[i].klitirqd->comm, klitirqds[i].klitirqd->pid,
89 (klitirqds[i].current_owner != NULL) ?
90 klitirqds[i].current_owner->comm : "(null)",
91 (klitirqds[i].current_owner != NULL) ?
92 klitirqds[i].current_owner->pid : 0,
93 klitirqds[i].pending,
94 atomic_read(&klitirqds[i].num_hi_pending),
95 atomic_read(&klitirqds[i].num_low_pending),
96 atomic_read(&klitirqds[i].num_work_pending));
97 }
98 }
99
100 return(len);
101}
102
103
104
105
106
107#if 0
108static atomic_t dump_id = ATOMIC_INIT(0);
109
110static void __dump_state(struct klitirqd_info* which, const char* caller)
111{
112 struct tasklet_struct* list;
113
114 int id = atomic_inc_return(&dump_id);
115
116 //if(in_interrupt())
117 {
118 if(which->current_owner)
119 {
120 TRACE("(id: %d caller: %s)\n"
121 "klitirqd: %s/%d\n"
122 "current owner: %s/%d\n"
123 "pending: %x\n",
124 id, caller,
125 which->klitirqd->comm, which->klitirqd->pid,
126 which->current_owner->comm, which->current_owner->pid,
127 which->pending);
128 }
129 else
130 {
131 TRACE("(id: %d caller: %s)\n"
132 "klitirqd: %s/%d\n"
133 "current owner: %p\n"
134 "pending: %x\n",
135 id, caller,
136 which->klitirqd->comm, which->klitirqd->pid,
137 NULL,
138 which->pending);
139 }
140
141 list = which->pending_tasklets.head;
142 while(list)
143 {
144 struct tasklet_struct *t = list;
145 list = list->next; /* advance */
146 if(t->owner)
147 TRACE("(id: %d caller: %s) Tasklet: %x, Owner = %s/%d\n", id, caller, t, t->owner->comm, t->owner->pid);
148 else
149 TRACE("(id: %d caller: %s) Tasklet: %x, Owner = %p\n", id, caller, t, NULL);
150 }
151 }
152}
153
154static void dump_state(struct klitirqd_info* which, const char* caller)
155{
156 unsigned long flags;
157
158 raw_spin_lock_irqsave(&which->lock, flags);
159 __dump_state(which, caller);
160 raw_spin_unlock_irqrestore(&which->lock, flags);
161}
162#endif
163
164
165/* forward declarations */
166static void ___litmus_tasklet_schedule(struct tasklet_struct *t,
167 struct klitirqd_info *which,
168 int wakeup);
169static void ___litmus_tasklet_hi_schedule(struct tasklet_struct *t,
170 struct klitirqd_info *which,
171 int wakeup);
172static void ___litmus_schedule_work(struct work_struct *w,
173 struct klitirqd_info *which,
174 int wakeup);
175
176
177
178inline unsigned int klitirqd_id(struct task_struct* tsk)
179{
180 int i;
181 for(i = 0; i < NR_LITMUS_SOFTIRQD; ++i)
182 {
183 if(klitirqds[i].klitirqd == tsk)
184 {
185 return i;
186 }
187 }
188
189 BUG();
190
191 return 0;
192}
193
194
195inline static u32 litirq_pending_hi_irqoff(struct klitirqd_info* which)
196{
197 return (which->pending & LIT_TASKLET_HI);
198}
199
200inline static u32 litirq_pending_low_irqoff(struct klitirqd_info* which)
201{
202 return (which->pending & LIT_TASKLET_LOW);
203}
204
205inline static u32 litirq_pending_work_irqoff(struct klitirqd_info* which)
206{
207 return (which->pending & LIT_WORK);
208}
209
210inline static u32 litirq_pending_irqoff(struct klitirqd_info* which)
211{
212 return(which->pending);
213}
214
215
216inline static u32 litirq_pending(struct klitirqd_info* which)
217{
218 unsigned long flags;
219 u32 pending;
220
221 raw_spin_lock_irqsave(&which->lock, flags);
222 pending = litirq_pending_irqoff(which);
223 raw_spin_unlock_irqrestore(&which->lock, flags);
224
225 return pending;
226};
227
228inline static u32 litirq_pending_with_owner(struct klitirqd_info* which, struct task_struct* owner)
229{
230 unsigned long flags;
231 u32 pending;
232
233 raw_spin_lock_irqsave(&which->lock, flags);
234 pending = litirq_pending_irqoff(which);
235 if(pending)
236 {
237 if(which->current_owner != owner)
238 {
239 pending = 0; // owner switch!
240 }
241 }
242 raw_spin_unlock_irqrestore(&which->lock, flags);
243
244 return pending;
245}
246
247
248inline static u32 litirq_pending_and_sem_and_owner(struct klitirqd_info* which,
249 struct mutex** sem,
250 struct task_struct** t)
251{
252 unsigned long flags;
253 u32 pending;
254
255 /* init values */
256 *sem = NULL;
257 *t = NULL;
258
259 raw_spin_lock_irqsave(&which->lock, flags);
260
261 pending = litirq_pending_irqoff(which);
262 if(pending)
263 {
264 if(which->current_owner != NULL)
265 {
266 *t = which->current_owner;
267 *sem = &tsk_rt(which->current_owner)->klitirqd_sem;
268 }
269 else
270 {
271 BUG();
272 }
273 }
274 raw_spin_unlock_irqrestore(&which->lock, flags);
275
276 if(likely(*sem))
277 {
278 return pending;
279 }
280 else
281 {
282 return 0;
283 }
284}
285
286/* returns true if the next piece of work to do is from a different owner.
287 */
288static int tasklet_ownership_change(
289 struct klitirqd_info* which,
290 enum pending_flags taskletQ)
291{
292 /* this function doesn't have to look at work objects since they have
293 priority below tasklets. */
294
295 unsigned long flags;
296 int ret = 0;
297
298 raw_spin_lock_irqsave(&which->lock, flags);
299
300 switch(taskletQ)
301 {
302 case LIT_TASKLET_HI:
303 if(litirq_pending_hi_irqoff(which))
304 {
305 ret = (which->pending_tasklets_hi.head->owner !=
306 which->current_owner);
307 }
308 break;
309 case LIT_TASKLET_LOW:
310 if(litirq_pending_low_irqoff(which))
311 {
312 ret = (which->pending_tasklets.head->owner !=
313 which->current_owner);
314 }
315 break;
316 default:
317 break;
318 }
319
320 raw_spin_unlock_irqrestore(&which->lock, flags);
321
322 TRACE_TASK(which->klitirqd, "ownership change needed: %d\n", ret);
323
324 return ret;
325}
326
327
328static void __reeval_prio(struct klitirqd_info* which)
329{
330 struct task_struct* next_owner = NULL;
331 struct task_struct* klitirqd = which->klitirqd;
332
333 /* Check in prio-order */
334 u32 pending = litirq_pending_irqoff(which);
335
336 //__dump_state(which, "__reeval_prio: before");
337
338 if(pending)
339 {
340 if(pending & LIT_TASKLET_HI)
341 {
342 next_owner = which->pending_tasklets_hi.head->owner;
343 }
344 else if(pending & LIT_TASKLET_LOW)
345 {
346 next_owner = which->pending_tasklets.head->owner;
347 }
348 else if(pending & LIT_WORK)
349 {
350 struct work_struct* work =
351 list_first_entry(&which->worklist, struct work_struct, entry);
352 next_owner = work->owner;
353 }
354 }
355
356 if(next_owner != which->current_owner)
357 {
358 struct task_struct* old_owner = which->current_owner;
359
360 /* bind the next owner. */
361 which->current_owner = next_owner;
362 mb();
363
364 if(next_owner != NULL)
365 {
366 if(!in_interrupt())
367 {
368 TRACE_CUR("%s: Ownership change: %s/%d to %s/%d\n", __FUNCTION__,
369 ((tsk_rt(klitirqd)->inh_task) ? tsk_rt(klitirqd)->inh_task : klitirqd)->comm,
370 ((tsk_rt(klitirqd)->inh_task) ? tsk_rt(klitirqd)->inh_task : klitirqd)->pid,
371 next_owner->comm, next_owner->pid);
372 }
373 else
374 {
375 TRACE("%s: Ownership change: %s/%d to %s/%d\n", __FUNCTION__,
376 ((tsk_rt(klitirqd)->inh_task) ? tsk_rt(klitirqd)->inh_task : klitirqd)->comm,
377 ((tsk_rt(klitirqd)->inh_task) ? tsk_rt(klitirqd)->inh_task : klitirqd)->pid,
378 next_owner->comm, next_owner->pid);
379 }
380
381 litmus->increase_prio_inheritance_klitirqd(klitirqd, old_owner, next_owner);
382 }
383 else
384 {
385 if(likely(!in_interrupt()))
386 {
387 TRACE_CUR("%s: Ownership change: %s/%d to NULL (reverting)\n",
388 __FUNCTION__, klitirqd->comm, klitirqd->pid);
389 }
390 else
391 {
392 // is this a bug?
393 TRACE("%s: Ownership change: %s/%d to NULL (reverting)\n",
394 __FUNCTION__, klitirqd->comm, klitirqd->pid);
395 }
396
397 BUG_ON(pending != 0);
398 litmus->decrease_prio_inheritance_klitirqd(klitirqd, old_owner, NULL);
399 }
400 }
401
402 //__dump_state(which, "__reeval_prio: after");
403}
404
405static void reeval_prio(struct klitirqd_info* which)
406{
407 unsigned long flags;
408
409 raw_spin_lock_irqsave(&which->lock, flags);
410 __reeval_prio(which);
411 raw_spin_unlock_irqrestore(&which->lock, flags);
412}
413
414
415static void wakeup_litirqd_locked(struct klitirqd_info* which)
416{
417 /* Interrupts are disabled: no need to stop preemption */
418 if (which && which->klitirqd)
419 {
420 __reeval_prio(which); /* configure the proper priority */
421
422 if(which->klitirqd->state != TASK_RUNNING)
423 {
424 TRACE("%s: Waking up klitirqd: %s/%d\n", __FUNCTION__,
425 which->klitirqd->comm, which->klitirqd->pid);
426
427 wake_up_process(which->klitirqd);
428 }
429 }
430}
431
432
433static void do_lit_tasklet(struct klitirqd_info* which,
434 struct tasklet_head* pending_tasklets)
435{
436 unsigned long flags;
437 struct tasklet_struct *list;
438 atomic_t* count;
439
440 raw_spin_lock_irqsave(&which->lock, flags);
441
442 //__dump_state(which, "do_lit_tasklet: before steal");
443
444 /* copy out the tasklets for our private use. */
445 list = pending_tasklets->head;
446 pending_tasklets->head = NULL;
447 pending_tasklets->tail = &pending_tasklets->head;
448
449 /* remove pending flag */
450 which->pending &= (pending_tasklets == &which->pending_tasklets) ?
451 ~LIT_TASKLET_LOW :
452 ~LIT_TASKLET_HI;
453
454 count = (pending_tasklets == &which->pending_tasklets) ?
455 &which->num_low_pending:
456 &which->num_hi_pending;
457
458 //__dump_state(which, "do_lit_tasklet: after steal");
459
460 raw_spin_unlock_irqrestore(&which->lock, flags);
461
462
463 while(list)
464 {
465 struct tasklet_struct *t = list;
466
467 /* advance, lest we forget */
468 list = list->next;
469
470 /* execute tasklet if it has my priority and is free */
471 if ((t->owner == which->current_owner) && tasklet_trylock(t)) {
472 if (!atomic_read(&t->count)) {
473
474 sched_trace_tasklet_begin(t->owner);
475
476 if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
477 {
478 BUG();
479 }
480 TRACE_CUR("%s: Invoking tasklet.\n", __FUNCTION__);
481 t->func(t->data);
482 tasklet_unlock(t);
483
484 atomic_dec(count);
485
486 sched_trace_tasklet_end(t->owner, 0ul);
487
488 continue; /* process more tasklets */
489 }
490 tasklet_unlock(t);
491 }
492
493 TRACE_CUR("%s: Could not invoke tasklet. Requeuing.\n", __FUNCTION__);
494
495 /* couldn't process tasklet. put it back at the end of the queue. */
496 if(pending_tasklets == &which->pending_tasklets)
497 ___litmus_tasklet_schedule(t, which, 0);
498 else
499 ___litmus_tasklet_hi_schedule(t, which, 0);
500 }
501}
502
503
504// returns 1 if priorities need to be changed to continue processing
505// pending tasklets.
506static int do_litirq(struct klitirqd_info* which)
507{
508 u32 pending;
509 int resched = 0;
510
511 if(in_interrupt())
512 {
513 TRACE("%s: exiting early: in interrupt context!\n", __FUNCTION__);
514 return(0);
515 }
516
517 if(which->klitirqd != current)
518 {
519 TRACE_CUR("%s: exiting early: thread/info mismatch! Running %s/%d but given %s/%d.\n",
520 __FUNCTION__, current->comm, current->pid,
521 which->klitirqd->comm, which->klitirqd->pid);
522 return(0);
523 }
524
525 if(!is_realtime(current))
526 {
527 TRACE_CUR("%s: exiting early: klitirqd is not real-time. Sched Policy = %d\n",
528 __FUNCTION__, current->policy);
529 return(0);
530 }
531
532
533 /* We only handle tasklets & work objects, no need for RCU triggers? */
534
535 pending = litirq_pending(which);
536 if(pending)
537 {
538 /* extract the work to do and do it! */
539 if(pending & LIT_TASKLET_HI)
540 {
541 TRACE_CUR("%s: Invoking HI tasklets.\n", __FUNCTION__);
542 do_lit_tasklet(which, &which->pending_tasklets_hi);
543 resched = tasklet_ownership_change(which, LIT_TASKLET_HI);
544
545 if(resched)
546 {
547 TRACE_CUR("%s: HI tasklets of another owner remain. "
548 "Skipping any LOW tasklets.\n", __FUNCTION__);
549 }
550 }
551
552 if(!resched && (pending & LIT_TASKLET_LOW))
553 {
554 TRACE_CUR("%s: Invoking LOW tasklets.\n", __FUNCTION__);
555 do_lit_tasklet(which, &which->pending_tasklets);
556 resched = tasklet_ownership_change(which, LIT_TASKLET_LOW);
557
558 if(resched)
559 {
560 TRACE_CUR("%s: LOW tasklets of another owner remain. "
561 "Skipping any work objects.\n", __FUNCTION__);
562 }
563 }
564 }
565
566 return(resched);
567}
568
569
570static void do_work(struct klitirqd_info* which)
571{
572 unsigned long flags;
573 work_func_t f;
574 struct work_struct* work;
575
576 // only execute one work-queue item to yield to tasklets.
577 // ...is this a good idea, or should we just batch them?
578 raw_spin_lock_irqsave(&which->lock, flags);
579
580 if(!litirq_pending_work_irqoff(which))
581 {
582 raw_spin_unlock_irqrestore(&which->lock, flags);
583 goto no_work;
584 }
585
586 work = list_first_entry(&which->worklist, struct work_struct, entry);
587 list_del_init(&work->entry);
588
589 if(list_empty(&which->worklist))
590 {
591 which->pending &= ~LIT_WORK;
592 }
593
594 raw_spin_unlock_irqrestore(&which->lock, flags);
595
596
597
598 /* safe to read current_owner outside of lock since only this thread
599 may write to the pointer. */
600 if(work->owner == which->current_owner)
601 {
602 TRACE_CUR("%s: Invoking work object.\n", __FUNCTION__);
603 // do the work!
604 work_clear_pending(work);
605 f = work->func;
606 f(work); /* can't touch 'work' after this point,
607 the user may have freed it. */
608
609 atomic_dec(&which->num_work_pending);
610 }
611 else
612 {
613 TRACE_CUR("%s: Could not invoke work object. Requeuing.\n",
614 __FUNCTION__);
615 ___litmus_schedule_work(work, which, 0);
616 }
617
618no_work:
619 return;
620}
621
622
623static int set_litmus_daemon_sched(void)
624{
625 /* set up a daemon job that will never complete.
626 it should only ever run on behalf of another
627 real-time task.
628
629 TODO: Transition to a new job whenever a
630 new tasklet is handled */
631
632 int ret = 0;
633
634 struct rt_task tp = {
635 .exec_cost = 0,
636 .period = 1000000000, /* dummy 1 second period */
637 .phase = 0,
638 .cpu = task_cpu(current),
639 .budget_policy = NO_ENFORCEMENT,
640 .cls = RT_CLASS_BEST_EFFORT
641 };
642
643 struct sched_param param = { .sched_priority = 0};
644
645
646 /* set task params, mark as proxy thread, and init other data */
647 tsk_rt(current)->task_params = tp;
648 tsk_rt(current)->is_proxy_thread = 1;
649 tsk_rt(current)->cur_klitirqd = NULL;
650 mutex_init(&tsk_rt(current)->klitirqd_sem);
651 atomic_set(&tsk_rt(current)->klitirqd_sem_stat, NOT_HELD);
652
653 /* inform the OS we're SCHED_LITMUS --
654 sched_setscheduler_nocheck() calls litmus_admit_task(). */
655 sched_setscheduler_nocheck(current, SCHED_LITMUS, &param);
656
657 return ret;
658}
659
660static void enter_execution_phase(struct klitirqd_info* which,
661 struct mutex* sem,
662 struct task_struct* t)
663{
664 TRACE_CUR("%s: Trying to enter execution phase. "
665 "Acquiring semaphore of %s/%d\n", __FUNCTION__,
666 t->comm, t->pid);
667 down_and_set_stat(current, HELD, sem);
668 TRACE_CUR("%s: Execution phase entered! "
669 "Acquired semaphore of %s/%d\n", __FUNCTION__,
670 t->comm, t->pid);
671}
672
673static void exit_execution_phase(struct klitirqd_info* which,
674 struct mutex* sem,
675 struct task_struct* t)
676{
677 TRACE_CUR("%s: Exiting execution phase. "
678 "Releasing semaphore of %s/%d\n", __FUNCTION__,
679 t->comm, t->pid);
680 if(atomic_read(&tsk_rt(current)->klitirqd_sem_stat) == HELD)
681 {
682 up_and_set_stat(current, NOT_HELD, sem);
683 TRACE_CUR("%s: Execution phase exited! "
684 "Released semaphore of %s/%d\n", __FUNCTION__,
685 t->comm, t->pid);
686 }
687 else
688 {
689 TRACE_CUR("%s: COULDN'T RELEASE SEMAPHORE BECAUSE ONE IS NOT HELD!\n", __FUNCTION__);
690 }
691}
692
693/* main loop for klitsoftirqd */
694static int run_klitirqd(void* unused)
695{
696 struct klitirqd_info* which = &klitirqds[klitirqd_id(current)];
697 struct mutex* sem;
698 struct task_struct* owner;
699
700 int rt_status = set_litmus_daemon_sched();
701
702 if(rt_status != 0)
703 {
704 TRACE_CUR("%s: Failed to transition to rt-task.\n", __FUNCTION__);
705 goto rt_failed;
706 }
707
708 atomic_inc(&num_ready_klitirqds);
709
710 set_current_state(TASK_INTERRUPTIBLE);
711
712 while (!kthread_should_stop())
713 {
714 preempt_disable();
715 if (!litirq_pending(which))
716 {
717 /* sleep for work */
718 TRACE_CUR("%s: No more tasklets or work objects. Going to sleep.\n",
719 __FUNCTION__);
720 preempt_enable_no_resched();
721 schedule();
722
723 if(kthread_should_stop()) /* bail out */
724 {
725 TRACE_CUR("%s:%d: Signaled to terminate.\n", __FUNCTION__, __LINE__);
726 continue;
727 }
728
729 preempt_disable();
730 }
731
732 __set_current_state(TASK_RUNNING);
733
734 while (litirq_pending_and_sem_and_owner(which, &sem, &owner))
735 {
736 int needs_resched = 0;
737
738 preempt_enable_no_resched();
739
740 BUG_ON(sem == NULL);
741
742 // wait to enter execution phase; wait for 'current_owner' to block.
743 enter_execution_phase(which, sem, owner);
744
745 if(kthread_should_stop())
746 {
747 TRACE_CUR("%s:%d: Signaled to terminate.\n", __FUNCTION__, __LINE__);
748 break;
749 }
750
751 preempt_disable();
752
753 /* Double check that there's still pending work and the owner hasn't
754 * changed. Pending items may have been flushed while we were sleeping.
755 */
756 if(litirq_pending_with_owner(which, owner))
757 {
758 TRACE_CUR("%s: Executing tasklets and/or work objects.\n",
759 __FUNCTION__);
760
761 needs_resched = do_litirq(which);
762
763 preempt_enable_no_resched();
764
765 // work objects are preemptible.
766 if(!needs_resched)
767 {
768 do_work(which);
769 }
770
771 // exit execution phase.
772 exit_execution_phase(which, sem, owner);
773
774 TRACE_CUR("%s: Setting up next priority.\n", __FUNCTION__);
775 reeval_prio(which); /* check if we need to change priority here */
776 }
777 else
778 {
779 TRACE_CUR("%s: Pending work was flushed! Prev owner was %s/%d\n",
780 __FUNCTION__,
781 owner->comm, owner->pid);
782 preempt_enable_no_resched();
783
784 // exit execution phase.
785 exit_execution_phase(which, sem, owner);
786 }
787
788 cond_resched();
789 preempt_disable();
790 }
791 preempt_enable();
792 set_current_state(TASK_INTERRUPTIBLE);
793 }
794 __set_current_state(TASK_RUNNING);
795
796 atomic_dec(&num_ready_klitirqds);
797
798rt_failed:
799 litmus_exit_task(current);
800
801 return rt_status;
802}
803
804
805struct klitirqd_launch_data
806{
807 int* cpu_affinity;
808 struct work_struct work;
809};
810
811/* executed by a kworker from workqueues */
812static void launch_klitirqd(struct work_struct *work)
813{
814 int i;
815
816 struct klitirqd_launch_data* launch_data =
817 container_of(work, struct klitirqd_launch_data, work);
818
819 TRACE("%s: Creating %d klitirqds\n", __FUNCTION__, NR_LITMUS_SOFTIRQD);
820
821 /* create the daemon threads */
822 for(i = 0; i < NR_LITMUS_SOFTIRQD; ++i)
823 {
824 if(launch_data->cpu_affinity)
825 {
826 klitirqds[i].klitirqd =
827 kthread_create(
828 run_klitirqd,
829 /* treat the affinity as a pointer, we'll cast it back later */
830 (void*)(long long)launch_data->cpu_affinity[i],
831 "klitirqd_th%d/%d",
832 i,
833 launch_data->cpu_affinity[i]);
834
835 /* litmus will put is in the right cluster. */
836 kthread_bind(klitirqds[i].klitirqd, launch_data->cpu_affinity[i]);
837 }
838 else
839 {
840 klitirqds[i].klitirqd =
841 kthread_create(
842 run_klitirqd,
843 /* treat the affinity as a pointer, we'll cast it back later */
844 (void*)(long long)(-1),
845 "klitirqd_th%d",
846 i);
847 }
848 }
849
850 TRACE("%s: Launching %d klitirqds\n", __FUNCTION__, NR_LITMUS_SOFTIRQD);
851
852 /* unleash the daemons */
853 for(i = 0; i < NR_LITMUS_SOFTIRQD; ++i)
854 {
855 wake_up_process(klitirqds[i].klitirqd);
856 }
857
858 if(launch_data->cpu_affinity)
859 kfree(launch_data->cpu_affinity);
860 kfree(launch_data);
861}
862
863
864void spawn_klitirqd(int* affinity)
865{
866 int i;
867 struct klitirqd_launch_data* delayed_launch;
868
869 if(atomic_read(&num_ready_klitirqds) != 0)
870 {
871 TRACE("%s: At least one klitirqd is already running! Need to call kill_klitirqd()?\n");
872 return;
873 }
874
875 /* init the tasklet & work queues */
876 for(i = 0; i < NR_LITMUS_SOFTIRQD; ++i)
877 {
878 klitirqds[i].terminating = 0;
879 klitirqds[i].pending = 0;
880
881 klitirqds[i].num_hi_pending.counter = 0;
882 klitirqds[i].num_low_pending.counter = 0;
883 klitirqds[i].num_work_pending.counter = 0;
884
885 klitirqds[i].pending_tasklets_hi.head = NULL;
886 klitirqds[i].pending_tasklets_hi.tail = &klitirqds[i].pending_tasklets_hi.head;
887
888 klitirqds[i].pending_tasklets.head = NULL;
889 klitirqds[i].pending_tasklets.tail = &klitirqds[i].pending_tasklets.head;
890
891 INIT_LIST_HEAD(&klitirqds[i].worklist);
892
893 raw_spin_lock_init(&klitirqds[i].lock);
894 }
895
896 /* wait to flush the initializations to memory since other threads
897 will access it. */
898 mb();
899
900 /* tell a work queue to launch the threads. we can't make scheduling
901 calls since we're in an atomic state. */
902 TRACE("%s: Setting callback up to launch klitirqds\n", __FUNCTION__);
903 delayed_launch = kmalloc(sizeof(struct klitirqd_launch_data), GFP_ATOMIC);
904 if(affinity)
905 {
906 delayed_launch->cpu_affinity =
907 kmalloc(sizeof(int)*NR_LITMUS_SOFTIRQD, GFP_ATOMIC);
908
909 memcpy(delayed_launch->cpu_affinity, affinity,
910 sizeof(int)*NR_LITMUS_SOFTIRQD);
911 }
912 else
913 {
914 delayed_launch->cpu_affinity = NULL;
915 }
916 INIT_WORK(&delayed_launch->work, launch_klitirqd);
917 schedule_work(&delayed_launch->work);
918}
919
920
921void kill_klitirqd(void)
922{
923 if(!klitirqd_is_dead())
924 {
925 int i;
926
927 TRACE("%s: Killing %d klitirqds\n", __FUNCTION__, NR_LITMUS_SOFTIRQD);
928
929 for(i = 0; i < NR_LITMUS_SOFTIRQD; ++i)
930 {
931 if(klitirqds[i].terminating != 1)
932 {
933 klitirqds[i].terminating = 1;
934 mb(); /* just to be sure? */
935 flush_pending(klitirqds[i].klitirqd, NULL);
936
937 /* signal termination */
938 kthread_stop(klitirqds[i].klitirqd);
939 }
940 }
941 }
942}
943
944
945int klitirqd_is_ready(void)
946{
947 return(atomic_read(&num_ready_klitirqds) == NR_LITMUS_SOFTIRQD);
948}
949
950int klitirqd_is_dead(void)
951{
952 return(atomic_read(&num_ready_klitirqds) == 0);
953}
954
955
956struct task_struct* get_klitirqd(unsigned int k_id)
957{
958 return(klitirqds[k_id].klitirqd);
959}
960
961
962void flush_pending(struct task_struct* klitirqd_thread,
963 struct task_struct* owner)
964{
965 unsigned int k_id = klitirqd_id(klitirqd_thread);
966 struct klitirqd_info *which = &klitirqds[k_id];
967
968 unsigned long flags;
969 struct tasklet_struct *list;
970
971 u32 work_flushed = 0;
972
973 raw_spin_lock_irqsave(&which->lock, flags);
974
975 //__dump_state(which, "flush_pending: before");
976
977 // flush hi tasklets.
978 if(litirq_pending_hi_irqoff(which))
979 {
980 which->pending &= ~LIT_TASKLET_HI;
981
982 list = which->pending_tasklets_hi.head;
983 which->pending_tasklets_hi.head = NULL;
984 which->pending_tasklets_hi.tail = &which->pending_tasklets_hi.head;
985
986 TRACE("%s: Handing HI tasklets back to Linux.\n", __FUNCTION__);
987
988 while(list)
989 {
990 struct tasklet_struct *t = list;
991 list = list->next;
992
993 if(likely((t->owner == owner) || (owner == NULL)))
994 {
995 if(unlikely(!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)))
996 {
997 BUG();
998 }
999
1000 work_flushed |= LIT_TASKLET_HI;
1001
1002 t->owner = NULL;
1003
1004 // WTF?
1005 if(!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
1006 {
1007 atomic_dec(&which->num_hi_pending);
1008 ___tasklet_hi_schedule(t);
1009 }
1010 else
1011 {
1012 TRACE("%s: dropped hi tasklet??\n", __FUNCTION__);
1013 BUG();
1014 }
1015 }
1016 else
1017 {
1018 TRACE("%s: Could not flush a HI tasklet.\n", __FUNCTION__);
1019 // put back on queue.
1020 ___litmus_tasklet_hi_schedule(t, which, 0);
1021 }
1022 }
1023 }
1024
1025 // flush low tasklets.
1026 if(litirq_pending_low_irqoff(which))
1027 {
1028 which->pending &= ~LIT_TASKLET_LOW;
1029
1030 list = which->pending_tasklets.head;
1031 which->pending_tasklets.head = NULL;
1032 which->pending_tasklets.tail = &which->pending_tasklets.head;
1033
1034 TRACE("%s: Handing LOW tasklets back to Linux.\n", __FUNCTION__);
1035
1036 while(list)
1037 {
1038 struct tasklet_struct *t = list;
1039 list = list->next;
1040
1041 if(likely((t->owner == owner) || (owner == NULL)))
1042 {
1043 if(unlikely(!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)))
1044 {
1045 BUG();
1046 }
1047
1048 work_flushed |= LIT_TASKLET_LOW;
1049
1050 t->owner = NULL;
1051 sched_trace_tasklet_end(owner, 1ul);
1052
1053 if(!test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
1054 {
1055 atomic_dec(&which->num_low_pending);
1056 ___tasklet_schedule(t);
1057 }
1058 else
1059 {
1060 TRACE("%s: dropped tasklet??\n", __FUNCTION__);
1061 BUG();
1062 }
1063 }
1064 else
1065 {
1066 TRACE("%s: Could not flush a LOW tasklet.\n", __FUNCTION__);
1067 // put back on queue
1068 ___litmus_tasklet_schedule(t, which, 0);
1069 }
1070 }
1071 }
1072
1073 // flush work objects
1074 if(litirq_pending_work_irqoff(which))
1075 {
1076 which->pending &= ~LIT_WORK;
1077
1078 TRACE("%s: Handing work objects back to Linux.\n", __FUNCTION__);
1079
1080 while(!list_empty(&which->worklist))
1081 {
1082 struct work_struct* work =
1083 list_first_entry(&which->worklist, struct work_struct, entry);
1084 list_del_init(&work->entry);
1085
1086 if(likely((work->owner == owner) || (owner == NULL)))
1087 {
1088 work_flushed |= LIT_WORK;
1089 atomic_dec(&which->num_work_pending);
1090
1091 work->owner = NULL;
1092 sched_trace_work_end(owner, current, 1ul);
1093 __schedule_work(work);
1094 }
1095 else
1096 {
1097 TRACE("%s: Could not flush a work object.\n", __FUNCTION__);
1098 // put back on queue
1099 ___litmus_schedule_work(work, which, 0);
1100 }
1101 }
1102 }
1103
1104 //__dump_state(which, "flush_pending: after (before reeval prio)");
1105
1106
1107 mb(); /* commit changes to pending flags */
1108
1109 /* reset the scheduling priority */
1110 if(work_flushed)
1111 {
1112 __reeval_prio(which);
1113
1114 /* Try to offload flushed tasklets to Linux's ksoftirqd. */
1115 if(work_flushed & (LIT_TASKLET_LOW | LIT_TASKLET_HI))
1116 {
1117 wakeup_softirqd();
1118 }
1119 }
1120 else
1121 {
1122 TRACE_CUR("%s: no work flushed, so __reeval_prio() skipped\n", __FUNCTION__);
1123 }
1124
1125 raw_spin_unlock_irqrestore(&which->lock, flags);
1126}
1127
1128
1129
1130
1131static void ___litmus_tasklet_schedule(struct tasklet_struct *t,
1132 struct klitirqd_info *which,
1133 int wakeup)
1134{
1135 unsigned long flags;
1136 u32 old_pending;
1137
1138 t->next = NULL;
1139
1140 raw_spin_lock_irqsave(&which->lock, flags);
1141
1142 //__dump_state(which, "___litmus_tasklet_schedule: before queuing");
1143
1144 *(which->pending_tasklets.tail) = t;
1145 which->pending_tasklets.tail = &t->next;
1146
1147 old_pending = which->pending;
1148 which->pending |= LIT_TASKLET_LOW;
1149
1150 atomic_inc(&which->num_low_pending);
1151
1152 mb();
1153
1154 if(!old_pending && wakeup)
1155 {
1156 wakeup_litirqd_locked(which); /* wake up the klitirqd */
1157 }
1158
1159 //__dump_state(which, "___litmus_tasklet_schedule: after queuing");
1160
1161 raw_spin_unlock_irqrestore(&which->lock, flags);
1162}
1163
1164int __litmus_tasklet_schedule(struct tasklet_struct *t, unsigned int k_id)
1165{
1166 int ret = 0; /* assume failure */
1167 if(unlikely((t->owner == NULL) || !is_realtime(t->owner)))
1168 {
1169 TRACE("%s: No owner associated with this tasklet!\n", __FUNCTION__);
1170 BUG();
1171 }
1172
1173 if(unlikely(k_id >= NR_LITMUS_SOFTIRQD))
1174 {
1175 TRACE("%s: No klitirqd_th%d!\n", __FUNCTION__, k_id);
1176 BUG();
1177 }
1178
1179 if(likely(!klitirqds[k_id].terminating))
1180 {
1181 /* Can't accept tasklets while we're processing a workqueue
1182 because they're handled by the same thread. This case is
1183 very RARE.
1184
1185 TODO: Use a separate thread for work objects!!!!!!
1186 */
1187 if(likely(atomic_read(&klitirqds[k_id].num_work_pending) == 0))
1188 {
1189 ret = 1;
1190 ___litmus_tasklet_schedule(t, &klitirqds[k_id], 1);
1191 }
1192 else
1193 {
1194 TRACE("%s: rejected tasklet because of pending work.\n",
1195 __FUNCTION__);
1196 }
1197 }
1198 return(ret);
1199}
1200
1201EXPORT_SYMBOL(__litmus_tasklet_schedule);
1202
1203
1204static void ___litmus_tasklet_hi_schedule(struct tasklet_struct *t,
1205 struct klitirqd_info *which,
1206 int wakeup)
1207{
1208 unsigned long flags;
1209 u32 old_pending;
1210
1211 t->next = NULL;
1212
1213 raw_spin_lock_irqsave(&which->lock, flags);
1214
1215 *(which->pending_tasklets_hi.tail) = t;
1216 which->pending_tasklets_hi.tail = &t->next;
1217
1218 old_pending = which->pending;
1219 which->pending |= LIT_TASKLET_HI;
1220
1221 atomic_inc(&which->num_hi_pending);
1222
1223 mb();
1224
1225 if(!old_pending && wakeup)
1226 {
1227 wakeup_litirqd_locked(which); /* wake up the klitirqd */
1228 }
1229
1230 raw_spin_unlock_irqrestore(&which->lock, flags);
1231}
1232
1233int __litmus_tasklet_hi_schedule(struct tasklet_struct *t, unsigned int k_id)
1234{
1235 int ret = 0; /* assume failure */
1236 if(unlikely((t->owner == NULL) || !is_realtime(t->owner)))
1237 {
1238 TRACE("%s: No owner associated with this tasklet!\n", __FUNCTION__);
1239 BUG();
1240 }
1241
1242 if(unlikely(k_id >= NR_LITMUS_SOFTIRQD))
1243 {
1244 TRACE("%s: No klitirqd_th%d!\n", __FUNCTION__, k_id);
1245 BUG();
1246 }
1247
1248 if(unlikely(!klitirqd_is_ready()))
1249 {
1250 TRACE("%s: klitirqd is not ready!\n", __FUNCTION__, k_id);
1251 BUG();
1252 }
1253
1254 if(likely(!klitirqds[k_id].terminating))
1255 {
1256 if(likely(atomic_read(&klitirqds[k_id].num_work_pending) == 0))
1257 {
1258 ret = 1;
1259 ___litmus_tasklet_hi_schedule(t, &klitirqds[k_id], 1);
1260 }
1261 else
1262 {
1263 TRACE("%s: rejected tasklet because of pending work.\n",
1264 __FUNCTION__);
1265 }
1266 }
1267 return(ret);
1268}
1269
1270EXPORT_SYMBOL(__litmus_tasklet_hi_schedule);
1271
1272
1273int __litmus_tasklet_hi_schedule_first(struct tasklet_struct *t, unsigned int k_id)
1274{
1275 int ret = 0; /* assume failure */
1276 u32 old_pending;
1277
1278 BUG_ON(!irqs_disabled());
1279
1280 if(unlikely((t->owner == NULL) || !is_realtime(t->owner)))
1281 {
1282 TRACE("%s: No owner associated with this tasklet!\n", __FUNCTION__);
1283 BUG();
1284 }
1285
1286 if(unlikely(k_id >= NR_LITMUS_SOFTIRQD))
1287 {
1288 TRACE("%s: No klitirqd_th%u!\n", __FUNCTION__, k_id);
1289 BUG();
1290 }
1291
1292 if(unlikely(!klitirqd_is_ready()))
1293 {
1294 TRACE("%s: klitirqd is not ready!\n", __FUNCTION__, k_id);
1295 BUG();
1296 }
1297
1298 if(likely(!klitirqds[k_id].terminating))
1299 {
1300 raw_spin_lock(&klitirqds[k_id].lock);
1301
1302 if(likely(atomic_read(&klitirqds[k_id].num_work_pending) == 0))
1303 {
1304 ret = 1; // success!
1305
1306 t->next = klitirqds[k_id].pending_tasklets_hi.head;
1307 klitirqds[k_id].pending_tasklets_hi.head = t;
1308
1309 old_pending = klitirqds[k_id].pending;
1310 klitirqds[k_id].pending |= LIT_TASKLET_HI;
1311
1312 atomic_inc(&klitirqds[k_id].num_hi_pending);
1313
1314 mb();
1315
1316 if(!old_pending)
1317 wakeup_litirqd_locked(&klitirqds[k_id]); /* wake up the klitirqd */
1318 }
1319 else
1320 {
1321 TRACE("%s: rejected tasklet because of pending work.\n",
1322 __FUNCTION__);
1323 }
1324
1325 raw_spin_unlock(&klitirqds[k_id].lock);
1326 }
1327 return(ret);
1328}
1329
1330EXPORT_SYMBOL(__litmus_tasklet_hi_schedule_first);
1331
1332
1333
1334static void ___litmus_schedule_work(struct work_struct *w,
1335 struct klitirqd_info *which,
1336 int wakeup)
1337{
1338 unsigned long flags;
1339 u32 old_pending;
1340
1341 raw_spin_lock_irqsave(&which->lock, flags);
1342
1343 work_pending(w);
1344 list_add_tail(&w->entry, &which->worklist);
1345
1346 old_pending = which->pending;
1347 which->pending |= LIT_WORK;
1348
1349 atomic_inc(&which->num_work_pending);
1350
1351 mb();
1352
1353 if(!old_pending && wakeup)
1354 {
1355 wakeup_litirqd_locked(which); /* wakeup the klitirqd */
1356 }
1357
1358 raw_spin_unlock_irqrestore(&which->lock, flags);
1359}
1360
1361int __litmus_schedule_work(struct work_struct *w, unsigned int k_id)
1362{
1363 int ret = 1; /* assume success */
1364 if(unlikely(w->owner == NULL) || !is_realtime(w->owner))
1365 {
1366 TRACE("%s: No owner associated with this work object!\n", __FUNCTION__);
1367 BUG();
1368 }
1369
1370 if(unlikely(k_id >= NR_LITMUS_SOFTIRQD))
1371 {
1372 TRACE("%s: No klitirqd_th%u!\n", k_id);
1373 BUG();
1374 }
1375
1376 if(unlikely(!klitirqd_is_ready()))
1377 {
1378 TRACE("%s: klitirqd is not ready!\n", __FUNCTION__, k_id);
1379 BUG();
1380 }
1381
1382 if(likely(!klitirqds[k_id].terminating))
1383 ___litmus_schedule_work(w, &klitirqds[k_id], 1);
1384 else
1385 ret = 0;
1386 return(ret);
1387}
1388EXPORT_SYMBOL(__litmus_schedule_work);
1389
1390
1391static int set_klitirqd_sem_status(unsigned long stat)
1392{
1393 TRACE_CUR("SETTING STATUS FROM %d TO %d\n",
1394 atomic_read(&tsk_rt(current)->klitirqd_sem_stat),
1395 stat);
1396 atomic_set(&tsk_rt(current)->klitirqd_sem_stat, stat);
1397 //mb();
1398
1399 return(0);
1400}
1401
1402static int set_klitirqd_sem_status_if_not_held(unsigned long stat)
1403{
1404 if(atomic_read(&tsk_rt(current)->klitirqd_sem_stat) != HELD)
1405 {
1406 return(set_klitirqd_sem_status(stat));
1407 }
1408 return(-1);
1409}
1410
1411
1412void __down_and_reset_and_set_stat(struct task_struct* t,
1413 enum klitirqd_sem_status to_reset,
1414 enum klitirqd_sem_status to_set,
1415 struct mutex* sem)
1416{
1417#if 0
1418 struct rt_param* param = container_of(sem, struct rt_param, klitirqd_sem);
1419 struct task_struct* task = container_of(param, struct task_struct, rt_param);
1420
1421 TRACE_CUR("%s: entered. Locking semaphore of %s/%d\n",
1422 __FUNCTION__, task->comm, task->pid);
1423#endif
1424
1425 mutex_lock_sfx(sem,
1426 set_klitirqd_sem_status_if_not_held, to_reset,
1427 set_klitirqd_sem_status, to_set);
1428#if 0
1429 TRACE_CUR("%s: exiting. Have semaphore of %s/%d\n",
1430 __FUNCTION__, task->comm, task->pid);
1431#endif
1432}
1433
1434void down_and_set_stat(struct task_struct* t,
1435 enum klitirqd_sem_status to_set,
1436 struct mutex* sem)
1437{
1438#if 0
1439 struct rt_param* param = container_of(sem, struct rt_param, klitirqd_sem);
1440 struct task_struct* task = container_of(param, struct task_struct, rt_param);
1441
1442 TRACE_CUR("%s: entered. Locking semaphore of %s/%d\n",
1443 __FUNCTION__, task->comm, task->pid);
1444#endif
1445
1446 mutex_lock_sfx(sem,
1447 NULL, 0,
1448 set_klitirqd_sem_status, to_set);
1449
1450#if 0
1451 TRACE_CUR("%s: exiting. Have semaphore of %s/%d\n",
1452 __FUNCTION__, task->comm, task->pid);
1453#endif
1454}
1455
1456
1457void up_and_set_stat(struct task_struct* t,
1458 enum klitirqd_sem_status to_set,
1459 struct mutex* sem)
1460{
1461#if 0
1462 struct rt_param* param = container_of(sem, struct rt_param, klitirqd_sem);
1463 struct task_struct* task = container_of(param, struct task_struct, rt_param);
1464
1465 TRACE_CUR("%s: entered. Unlocking semaphore of %s/%d\n",
1466 __FUNCTION__,
1467 task->comm, task->pid);
1468#endif
1469
1470 mutex_unlock_sfx(sem, NULL, 0,
1471 set_klitirqd_sem_status, to_set);
1472
1473#if 0
1474 TRACE_CUR("%s: exiting. Unlocked semaphore of %s/%d\n",
1475 __FUNCTION__,
1476 task->comm, task->pid);
1477#endif
1478}
1479
1480
1481
1482void release_klitirqd_lock(struct task_struct* t)
1483{
1484 if(is_realtime(t) && (atomic_read(&tsk_rt(t)->klitirqd_sem_stat) == HELD))
1485 {
1486 struct mutex* sem;
1487 struct task_struct* owner = t;
1488
1489 if(t->state == TASK_RUNNING)
1490 {
1491 TRACE_TASK(t, "NOT giving up klitirqd_sem because we're not blocked!\n");
1492 return;
1493 }
1494
1495 if(likely(!tsk_rt(t)->is_proxy_thread))
1496 {
1497 sem = &tsk_rt(t)->klitirqd_sem;
1498 }
1499 else
1500 {
1501 unsigned int k_id = klitirqd_id(t);
1502 owner = klitirqds[k_id].current_owner;
1503
1504 BUG_ON(t != klitirqds[k_id].klitirqd);
1505
1506 if(likely(owner))
1507 {
1508 sem = &tsk_rt(owner)->klitirqd_sem;
1509 }
1510 else
1511 {
1512 BUG();
1513
1514 // We had the rug pulled out from under us. Abort attempt
1515 // to reacquire the lock since our client no longer needs us.
1516 TRACE_CUR("HUH?! How did this happen?\n");
1517 atomic_set(&tsk_rt(t)->klitirqd_sem_stat, NOT_HELD);
1518 return;
1519 }
1520 }
1521
1522 //TRACE_CUR("Releasing semaphore of %s/%d...\n", owner->comm, owner->pid);
1523 up_and_set_stat(t, NEED_TO_REACQUIRE, sem);
1524 //TRACE_CUR("Semaphore of %s/%d released!\n", owner->comm, owner->pid);
1525 }
1526 /*
1527 else if(is_realtime(t))
1528 {
1529 TRACE_CUR("%s: Nothing to do. Stat = %d\n", __FUNCTION__, tsk_rt(t)->klitirqd_sem_stat);
1530 }
1531 */
1532}
1533
1534int reacquire_klitirqd_lock(struct task_struct* t)
1535{
1536 int ret = 0;
1537
1538 if(is_realtime(t) && (atomic_read(&tsk_rt(t)->klitirqd_sem_stat) == NEED_TO_REACQUIRE))
1539 {
1540 struct mutex* sem;
1541 struct task_struct* owner = t;
1542
1543 if(likely(!tsk_rt(t)->is_proxy_thread))
1544 {
1545 sem = &tsk_rt(t)->klitirqd_sem;
1546 }
1547 else
1548 {
1549 unsigned int k_id = klitirqd_id(t);
1550 //struct task_struct* owner = klitirqds[k_id].current_owner;
1551 owner = klitirqds[k_id].current_owner;
1552
1553 BUG_ON(t != klitirqds[k_id].klitirqd);
1554
1555 if(likely(owner))
1556 {
1557 sem = &tsk_rt(owner)->klitirqd_sem;
1558 }
1559 else
1560 {
1561 // We had the rug pulled out from under us. Abort attempt
1562 // to reacquire the lock since our client no longer needs us.
1563 TRACE_CUR("No longer needs to reacquire klitirqd_sem!\n");
1564 atomic_set(&tsk_rt(t)->klitirqd_sem_stat, NOT_HELD);
1565 return(0);
1566 }
1567 }
1568
1569 //TRACE_CUR("Trying to reacquire semaphore of %s/%d\n", owner->comm, owner->pid);
1570 __down_and_reset_and_set_stat(t, REACQUIRING, HELD, sem);
1571 //TRACE_CUR("Reacquired semaphore %s/%d\n", owner->comm, owner->pid);
1572 }
1573 /*
1574 else if(is_realtime(t))
1575 {
1576 TRACE_CUR("%s: Nothing to do. Stat = %d\n", __FUNCTION__, tsk_rt(t)->klitirqd_sem_stat);
1577 }
1578 */
1579
1580 return(ret);
1581}
1582
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-10 00:28:15 -0500