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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* sched.c - SPU scheduler.
3 *
4 * Copyright (C) IBM 2005
5 * Author: Mark Nutter <mnutter@us.ibm.com>
6 *
7 * 2006-03-31 NUMA domains added.
8 */
9
10#undef DEBUG
11
12#include <linux/errno.h>
13#include <linux/sched/signal.h>
14#include <linux/sched/loadavg.h>
15#include <linux/sched/rt.h>
16#include <linux/kernel.h>
17#include <linux/mm.h>
18#include <linux/slab.h>
19#include <linux/completion.h>
20#include <linux/vmalloc.h>
21#include <linux/smp.h>
22#include <linux/stddef.h>
23#include <linux/unistd.h>
24#include <linux/numa.h>
25#include <linux/mutex.h>
26#include <linux/notifier.h>
27#include <linux/kthread.h>
28#include <linux/pid_namespace.h>
29#include <linux/proc_fs.h>
30#include <linux/seq_file.h>
31
32#include <asm/io.h>
33#include <asm/mmu_context.h>
34#include <asm/spu.h>
35#include <asm/spu_csa.h>
36#include <asm/spu_priv1.h>
37#include "spufs.h"
38#define CREATE_TRACE_POINTS
39#include "sputrace.h"
40
41struct spu_prio_array {
42 DECLARE_BITMAP(bitmap, MAX_PRIO);
43 struct list_head runq[MAX_PRIO];
44 spinlock_t runq_lock;
45 int nr_waiting;
46};
47
48static unsigned long spu_avenrun[3];
49static struct spu_prio_array *spu_prio;
50static struct task_struct *spusched_task;
51static struct timer_list spusched_timer;
52static struct timer_list spuloadavg_timer;
53
54/*
55 * Priority of a normal, non-rt, non-niced'd process (aka nice level 0).
56 */
57#define NORMAL_PRIO 120
58
59/*
60 * Frequency of the spu scheduler tick. By default we do one SPU scheduler
61 * tick for every 10 CPU scheduler ticks.
62 */
63#define SPUSCHED_TICK (10)
64
65/*
66 * These are the 'tuning knobs' of the scheduler:
67 *
68 * Minimum timeslice is 5 msecs (or 1 spu scheduler tick, whichever is
69 * larger), default timeslice is 100 msecs, maximum timeslice is 800 msecs.
70 */
71#define MIN_SPU_TIMESLICE max(5 * HZ / (1000 * SPUSCHED_TICK), 1)
72#define DEF_SPU_TIMESLICE (100 * HZ / (1000 * SPUSCHED_TICK))
73
74#define SCALE_PRIO(x, prio) \
75 max(x * (MAX_PRIO - prio) / (NICE_WIDTH / 2), MIN_SPU_TIMESLICE)
76
77/*
78 * scale user-nice values [ -20 ... 0 ... 19 ] to time slice values:
79 * [800ms ... 100ms ... 5ms]
80 *
81 * The higher a thread's priority, the bigger timeslices
82 * it gets during one round of execution. But even the lowest
83 * priority thread gets MIN_TIMESLICE worth of execution time.
84 */
85void spu_set_timeslice(struct spu_context *ctx)
86{
87 if (ctx->prio < NORMAL_PRIO)
88 ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE * 4, ctx->prio);
89 else
90 ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE, ctx->prio);
91}
92
93/*
94 * Update scheduling information from the owning thread.
95 */
96void __spu_update_sched_info(struct spu_context *ctx)
97{
98 /*
99 * assert that the context is not on the runqueue, so it is safe
100 * to change its scheduling parameters.
101 */
102 BUG_ON(!list_empty(&ctx->rq));
103
104 /*
105 * 32-Bit assignments are atomic on powerpc, and we don't care about
106 * memory ordering here because retrieving the controlling thread is
107 * per definition racy.
108 */
109 ctx->tid = current->pid;
110
111 /*
112 * We do our own priority calculations, so we normally want
113 * ->static_prio to start with. Unfortunately this field
114 * contains junk for threads with a realtime scheduling
115 * policy so we have to look at ->prio in this case.
116 */
117 if (rt_prio(current->prio))
118 ctx->prio = current->prio;
119 else
120 ctx->prio = current->static_prio;
121 ctx->policy = current->policy;
122
123 /*
124 * TO DO: the context may be loaded, so we may need to activate
125 * it again on a different node. But it shouldn't hurt anything
126 * to update its parameters, because we know that the scheduler
127 * is not actively looking at this field, since it is not on the
128 * runqueue. The context will be rescheduled on the proper node
129 * if it is timesliced or preempted.
130 */
131 cpumask_copy(&ctx->cpus_allowed, current->cpus_ptr);
132
133 /* Save the current cpu id for spu interrupt routing. */
134 ctx->last_ran = raw_smp_processor_id();
135}
136
137void spu_update_sched_info(struct spu_context *ctx)
138{
139 int node;
140
141 if (ctx->state == SPU_STATE_RUNNABLE) {
142 node = ctx->spu->node;
143
144 /*
145 * Take list_mutex to sync with find_victim().
146 */
147 mutex_lock(&cbe_spu_info[node].list_mutex);
148 __spu_update_sched_info(ctx);
149 mutex_unlock(&cbe_spu_info[node].list_mutex);
150 } else {
151 __spu_update_sched_info(ctx);
152 }
153}
154
155static int __node_allowed(struct spu_context *ctx, int node)
156{
157 if (nr_cpus_node(node)) {
158 const struct cpumask *mask = cpumask_of_node(node);
159
160 if (cpumask_intersects(mask, &ctx->cpus_allowed))
161 return 1;
162 }
163
164 return 0;
165}
166
167static int node_allowed(struct spu_context *ctx, int node)
168{
169 int rval;
170
171 spin_lock(&spu_prio->runq_lock);
172 rval = __node_allowed(ctx, node);
173 spin_unlock(&spu_prio->runq_lock);
174
175 return rval;
176}
177
178void do_notify_spus_active(void)
179{
180 int node;
181
182 /*
183 * Wake up the active spu_contexts.
184 */
185 for_each_online_node(node) {
186 struct spu *spu;
187
188 mutex_lock(&cbe_spu_info[node].list_mutex);
189 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
190 if (spu->alloc_state != SPU_FREE) {
191 struct spu_context *ctx = spu->ctx;
192 set_bit(SPU_SCHED_NOTIFY_ACTIVE,
193 &ctx->sched_flags);
194 mb();
195 wake_up_all(&ctx->stop_wq);
196 }
197 }
198 mutex_unlock(&cbe_spu_info[node].list_mutex);
199 }
200}
201
202/**
203 * spu_bind_context - bind spu context to physical spu
204 * @spu: physical spu to bind to
205 * @ctx: context to bind
206 */
207static void spu_bind_context(struct spu *spu, struct spu_context *ctx)
208{
209 spu_context_trace(spu_bind_context__enter, ctx, spu);
210
211 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
212
213 if (ctx->flags & SPU_CREATE_NOSCHED)
214 atomic_inc(&cbe_spu_info[spu->node].reserved_spus);
215
216 ctx->stats.slb_flt_base = spu->stats.slb_flt;
217 ctx->stats.class2_intr_base = spu->stats.class2_intr;
218
219 spu_associate_mm(spu, ctx->owner);
220
221 spin_lock_irq(&spu->register_lock);
222 spu->ctx = ctx;
223 spu->flags = 0;
224 ctx->spu = spu;
225 ctx->ops = &spu_hw_ops;
226 spu->pid = current->pid;
227 spu->tgid = current->tgid;
228 spu->ibox_callback = spufs_ibox_callback;
229 spu->wbox_callback = spufs_wbox_callback;
230 spu->stop_callback = spufs_stop_callback;
231 spu->mfc_callback = spufs_mfc_callback;
232 spin_unlock_irq(&spu->register_lock);
233
234 spu_unmap_mappings(ctx);
235
236 spu_switch_log_notify(spu, ctx, SWITCH_LOG_START, 0);
237 spu_restore(&ctx->csa, spu);
238 spu->timestamp = jiffies;
239 ctx->state = SPU_STATE_RUNNABLE;
240
241 spuctx_switch_state(ctx, SPU_UTIL_USER);
242}
243
244/*
245 * Must be used with the list_mutex held.
246 */
247static inline int sched_spu(struct spu *spu)
248{
249 BUG_ON(!mutex_is_locked(&cbe_spu_info[spu->node].list_mutex));
250
251 return (!spu->ctx || !(spu->ctx->flags & SPU_CREATE_NOSCHED));
252}
253
254static void aff_merge_remaining_ctxs(struct spu_gang *gang)
255{
256 struct spu_context *ctx;
257
258 list_for_each_entry(ctx, &gang->aff_list_head, aff_list) {
259 if (list_empty(&ctx->aff_list))
260 list_add(&ctx->aff_list, &gang->aff_list_head);
261 }
262 gang->aff_flags |= AFF_MERGED;
263}
264
265static void aff_set_offsets(struct spu_gang *gang)
266{
267 struct spu_context *ctx;
268 int offset;
269
270 offset = -1;
271 list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
272 aff_list) {
273 if (&ctx->aff_list == &gang->aff_list_head)
274 break;
275 ctx->aff_offset = offset--;
276 }
277
278 offset = 0;
279 list_for_each_entry(ctx, gang->aff_ref_ctx->aff_list.prev, aff_list) {
280 if (&ctx->aff_list == &gang->aff_list_head)
281 break;
282 ctx->aff_offset = offset++;
283 }
284
285 gang->aff_flags |= AFF_OFFSETS_SET;
286}
287
288static struct spu *aff_ref_location(struct spu_context *ctx, int mem_aff,
289 int group_size, int lowest_offset)
290{
291 struct spu *spu;
292 int node, n;
293
294 /*
295 * TODO: A better algorithm could be used to find a good spu to be
296 * used as reference location for the ctxs chain.
297 */
298 node = cpu_to_node(raw_smp_processor_id());
299 for (n = 0; n < MAX_NUMNODES; n++, node++) {
300 /*
301 * "available_spus" counts how many spus are not potentially
302 * going to be used by other affinity gangs whose reference
303 * context is already in place. Although this code seeks to
304 * avoid having affinity gangs with a summed amount of
305 * contexts bigger than the amount of spus in the node,
306 * this may happen sporadically. In this case, available_spus
307 * becomes negative, which is harmless.
308 */
309 int available_spus;
310
311 node = (node < MAX_NUMNODES) ? node : 0;
312 if (!node_allowed(ctx, node))
313 continue;
314
315 available_spus = 0;
316 mutex_lock(&cbe_spu_info[node].list_mutex);
317 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
318 if (spu->ctx && spu->ctx->gang && !spu->ctx->aff_offset
319 && spu->ctx->gang->aff_ref_spu)
320 available_spus -= spu->ctx->gang->contexts;
321 available_spus++;
322 }
323 if (available_spus < ctx->gang->contexts) {
324 mutex_unlock(&cbe_spu_info[node].list_mutex);
325 continue;
326 }
327
328 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
329 if ((!mem_aff || spu->has_mem_affinity) &&
330 sched_spu(spu)) {
331 mutex_unlock(&cbe_spu_info[node].list_mutex);
332 return spu;
333 }
334 }
335 mutex_unlock(&cbe_spu_info[node].list_mutex);
336 }
337 return NULL;
338}
339
340static void aff_set_ref_point_location(struct spu_gang *gang)
341{
342 int mem_aff, gs, lowest_offset;
343 struct spu_context *tmp, *ctx;
344
345 mem_aff = gang->aff_ref_ctx->flags & SPU_CREATE_AFFINITY_MEM;
346 lowest_offset = 0;
347 gs = 0;
348
349 list_for_each_entry(tmp, &gang->aff_list_head, aff_list)
350 gs++;
351
352 list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
353 aff_list) {
354 if (&ctx->aff_list == &gang->aff_list_head)
355 break;
356 lowest_offset = ctx->aff_offset;
357 }
358
359 gang->aff_ref_spu = aff_ref_location(gang->aff_ref_ctx, mem_aff, gs,
360 lowest_offset);
361}
362
363static struct spu *ctx_location(struct spu *ref, int offset, int node)
364{
365 struct spu *spu;
366
367 spu = NULL;
368 if (offset >= 0) {
369 list_for_each_entry(spu, ref->aff_list.prev, aff_list) {
370 BUG_ON(spu->node != node);
371 if (offset == 0)
372 break;
373 if (sched_spu(spu))
374 offset--;
375 }
376 } else {
377 list_for_each_entry_reverse(spu, ref->aff_list.next, aff_list) {
378 BUG_ON(spu->node != node);
379 if (offset == 0)
380 break;
381 if (sched_spu(spu))
382 offset++;
383 }
384 }
385
386 return spu;
387}
388
389/*
390 * affinity_check is called each time a context is going to be scheduled.
391 * It returns the spu ptr on which the context must run.
392 */
393static int has_affinity(struct spu_context *ctx)
394{
395 struct spu_gang *gang = ctx->gang;
396
397 if (list_empty(&ctx->aff_list))
398 return 0;
399
400 if (atomic_read(&ctx->gang->aff_sched_count) == 0)
401 ctx->gang->aff_ref_spu = NULL;
402
403 if (!gang->aff_ref_spu) {
404 if (!(gang->aff_flags & AFF_MERGED))
405 aff_merge_remaining_ctxs(gang);
406 if (!(gang->aff_flags & AFF_OFFSETS_SET))
407 aff_set_offsets(gang);
408 aff_set_ref_point_location(gang);
409 }
410
411 return gang->aff_ref_spu != NULL;
412}
413
414/**
415 * spu_unbind_context - unbind spu context from physical spu
416 * @spu: physical spu to unbind from
417 * @ctx: context to unbind
418 */
419static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
420{
421 u32 status;
422
423 spu_context_trace(spu_unbind_context__enter, ctx, spu);
424
425 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
426
427 if (spu->ctx->flags & SPU_CREATE_NOSCHED)
428 atomic_dec(&cbe_spu_info[spu->node].reserved_spus);
429
430 if (ctx->gang)
431 /*
432 * If ctx->gang->aff_sched_count is positive, SPU affinity is
433 * being considered in this gang. Using atomic_dec_if_positive
434 * allow us to skip an explicit check for affinity in this gang
435 */
436 atomic_dec_if_positive(&ctx->gang->aff_sched_count);
437
438 spu_unmap_mappings(ctx);
439 spu_save(&ctx->csa, spu);
440 spu_switch_log_notify(spu, ctx, SWITCH_LOG_STOP, 0);
441
442 spin_lock_irq(&spu->register_lock);
443 spu->timestamp = jiffies;
444 ctx->state = SPU_STATE_SAVED;
445 spu->ibox_callback = NULL;
446 spu->wbox_callback = NULL;
447 spu->stop_callback = NULL;
448 spu->mfc_callback = NULL;
449 spu->pid = 0;
450 spu->tgid = 0;
451 ctx->ops = &spu_backing_ops;
452 spu->flags = 0;
453 spu->ctx = NULL;
454 spin_unlock_irq(&spu->register_lock);
455
456 spu_associate_mm(spu, NULL);
457
458 ctx->stats.slb_flt +=
459 (spu->stats.slb_flt - ctx->stats.slb_flt_base);
460 ctx->stats.class2_intr +=
461 (spu->stats.class2_intr - ctx->stats.class2_intr_base);
462
463 /* This maps the underlying spu state to idle */
464 spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
465 ctx->spu = NULL;
466
467 if (spu_stopped(ctx, &status))
468 wake_up_all(&ctx->stop_wq);
469}
470
471/**
472 * spu_add_to_rq - add a context to the runqueue
473 * @ctx: context to add
474 */
475static void __spu_add_to_rq(struct spu_context *ctx)
476{
477 /*
478 * Unfortunately this code path can be called from multiple threads
479 * on behalf of a single context due to the way the problem state
480 * mmap support works.
481 *
482 * Fortunately we need to wake up all these threads at the same time
483 * and can simply skip the runqueue addition for every but the first
484 * thread getting into this codepath.
485 *
486 * It's still quite hacky, and long-term we should proxy all other
487 * threads through the owner thread so that spu_run is in control
488 * of all the scheduling activity for a given context.
489 */
490 if (list_empty(&ctx->rq)) {
491 list_add_tail(&ctx->rq, &spu_prio->runq[ctx->prio]);
492 set_bit(ctx->prio, spu_prio->bitmap);
493 if (!spu_prio->nr_waiting++)
494 mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
495 }
496}
497
498static void spu_add_to_rq(struct spu_context *ctx)
499{
500 spin_lock(&spu_prio->runq_lock);
501 __spu_add_to_rq(ctx);
502 spin_unlock(&spu_prio->runq_lock);
503}
504
505static void __spu_del_from_rq(struct spu_context *ctx)
506{
507 int prio = ctx->prio;
508
509 if (!list_empty(&ctx->rq)) {
510 if (!--spu_prio->nr_waiting)
511 del_timer(&spusched_timer);
512 list_del_init(&ctx->rq);
513
514 if (list_empty(&spu_prio->runq[prio]))
515 clear_bit(prio, spu_prio->bitmap);
516 }
517}
518
519void spu_del_from_rq(struct spu_context *ctx)
520{
521 spin_lock(&spu_prio->runq_lock);
522 __spu_del_from_rq(ctx);
523 spin_unlock(&spu_prio->runq_lock);
524}
525
526static void spu_prio_wait(struct spu_context *ctx)
527{
528 DEFINE_WAIT(wait);
529
530 /*
531 * The caller must explicitly wait for a context to be loaded
532 * if the nosched flag is set. If NOSCHED is not set, the caller
533 * queues the context and waits for an spu event or error.
534 */
535 BUG_ON(!(ctx->flags & SPU_CREATE_NOSCHED));
536
537 spin_lock(&spu_prio->runq_lock);
538 prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE);
539 if (!signal_pending(current)) {
540 __spu_add_to_rq(ctx);
541 spin_unlock(&spu_prio->runq_lock);
542 mutex_unlock(&ctx->state_mutex);
543 schedule();
544 mutex_lock(&ctx->state_mutex);
545 spin_lock(&spu_prio->runq_lock);
546 __spu_del_from_rq(ctx);
547 }
548 spin_unlock(&spu_prio->runq_lock);
549 __set_current_state(TASK_RUNNING);
550 remove_wait_queue(&ctx->stop_wq, &wait);
551}
552
553static struct spu *spu_get_idle(struct spu_context *ctx)
554{
555 struct spu *spu, *aff_ref_spu;
556 int node, n;
557
558 spu_context_nospu_trace(spu_get_idle__enter, ctx);
559
560 if (ctx->gang) {
561 mutex_lock(&ctx->gang->aff_mutex);
562 if (has_affinity(ctx)) {
563 aff_ref_spu = ctx->gang->aff_ref_spu;
564 atomic_inc(&ctx->gang->aff_sched_count);
565 mutex_unlock(&ctx->gang->aff_mutex);
566 node = aff_ref_spu->node;
567
568 mutex_lock(&cbe_spu_info[node].list_mutex);
569 spu = ctx_location(aff_ref_spu, ctx->aff_offset, node);
570 if (spu && spu->alloc_state == SPU_FREE)
571 goto found;
572 mutex_unlock(&cbe_spu_info[node].list_mutex);
573
574 atomic_dec(&ctx->gang->aff_sched_count);
575 goto not_found;
576 }
577 mutex_unlock(&ctx->gang->aff_mutex);
578 }
579 node = cpu_to_node(raw_smp_processor_id());
580 for (n = 0; n < MAX_NUMNODES; n++, node++) {
581 node = (node < MAX_NUMNODES) ? node : 0;
582 if (!node_allowed(ctx, node))
583 continue;
584
585 mutex_lock(&cbe_spu_info[node].list_mutex);
586 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
587 if (spu->alloc_state == SPU_FREE)
588 goto found;
589 }
590 mutex_unlock(&cbe_spu_info[node].list_mutex);
591 }
592
593 not_found:
594 spu_context_nospu_trace(spu_get_idle__not_found, ctx);
595 return NULL;
596
597 found:
598 spu->alloc_state = SPU_USED;
599 mutex_unlock(&cbe_spu_info[node].list_mutex);
600 spu_context_trace(spu_get_idle__found, ctx, spu);
601 spu_init_channels(spu);
602 return spu;
603}
604
605/**
606 * find_victim - find a lower priority context to preempt
607 * @ctx: candidate context for running
608 *
609 * Returns the freed physical spu to run the new context on.
610 */
611static struct spu *find_victim(struct spu_context *ctx)
612{
613 struct spu_context *victim = NULL;
614 struct spu *spu;
615 int node, n;
616
617 spu_context_nospu_trace(spu_find_victim__enter, ctx);
618
619 /*
620 * Look for a possible preemption candidate on the local node first.
621 * If there is no candidate look at the other nodes. This isn't
622 * exactly fair, but so far the whole spu scheduler tries to keep
623 * a strong node affinity. We might want to fine-tune this in
624 * the future.
625 */
626 restart:
627 node = cpu_to_node(raw_smp_processor_id());
628 for (n = 0; n < MAX_NUMNODES; n++, node++) {
629 node = (node < MAX_NUMNODES) ? node : 0;
630 if (!node_allowed(ctx, node))
631 continue;
632
633 mutex_lock(&cbe_spu_info[node].list_mutex);
634 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
635 struct spu_context *tmp = spu->ctx;
636
637 if (tmp && tmp->prio > ctx->prio &&
638 !(tmp->flags & SPU_CREATE_NOSCHED) &&
639 (!victim || tmp->prio > victim->prio)) {
640 victim = spu->ctx;
641 }
642 }
643 if (victim)
644 get_spu_context(victim);
645 mutex_unlock(&cbe_spu_info[node].list_mutex);
646
647 if (victim) {
648 /*
649 * This nests ctx->state_mutex, but we always lock
650 * higher priority contexts before lower priority
651 * ones, so this is safe until we introduce
652 * priority inheritance schemes.
653 *
654 * XXX if the highest priority context is locked,
655 * this can loop a long time. Might be better to
656 * look at another context or give up after X retries.
657 */
658 if (!mutex_trylock(&victim->state_mutex)) {
659 put_spu_context(victim);
660 victim = NULL;
661 goto restart;
662 }
663
664 spu = victim->spu;
665 if (!spu || victim->prio <= ctx->prio) {
666 /*
667 * This race can happen because we've dropped
668 * the active list mutex. Not a problem, just
669 * restart the search.
670 */
671 mutex_unlock(&victim->state_mutex);
672 put_spu_context(victim);
673 victim = NULL;
674 goto restart;
675 }
676
677 spu_context_trace(__spu_deactivate__unload, ctx, spu);
678
679 mutex_lock(&cbe_spu_info[node].list_mutex);
680 cbe_spu_info[node].nr_active--;
681 spu_unbind_context(spu, victim);
682 mutex_unlock(&cbe_spu_info[node].list_mutex);
683
684 victim->stats.invol_ctx_switch++;
685 spu->stats.invol_ctx_switch++;
686 if (test_bit(SPU_SCHED_SPU_RUN, &victim->sched_flags))
687 spu_add_to_rq(victim);
688
689 mutex_unlock(&victim->state_mutex);
690 put_spu_context(victim);
691
692 return spu;
693 }
694 }
695
696 return NULL;
697}
698
699static void __spu_schedule(struct spu *spu, struct spu_context *ctx)
700{
701 int node = spu->node;
702 int success = 0;
703
704 spu_set_timeslice(ctx);
705
706 mutex_lock(&cbe_spu_info[node].list_mutex);
707 if (spu->ctx == NULL) {
708 spu_bind_context(spu, ctx);
709 cbe_spu_info[node].nr_active++;
710 spu->alloc_state = SPU_USED;
711 success = 1;
712 }
713 mutex_unlock(&cbe_spu_info[node].list_mutex);
714
715 if (success)
716 wake_up_all(&ctx->run_wq);
717 else
718 spu_add_to_rq(ctx);
719}
720
721static void spu_schedule(struct spu *spu, struct spu_context *ctx)
722{
723 /* not a candidate for interruptible because it's called either
724 from the scheduler thread or from spu_deactivate */
725 mutex_lock(&ctx->state_mutex);
726 if (ctx->state == SPU_STATE_SAVED)
727 __spu_schedule(spu, ctx);
728 spu_release(ctx);
729}
730
731/**
732 * spu_unschedule - remove a context from a spu, and possibly release it.
733 * @spu: The SPU to unschedule from
734 * @ctx: The context currently scheduled on the SPU
735 * @free_spu Whether to free the SPU for other contexts
736 *
737 * Unbinds the context @ctx from the SPU @spu. If @free_spu is non-zero, the
738 * SPU is made available for other contexts (ie, may be returned by
739 * spu_get_idle). If this is zero, the caller is expected to schedule another
740 * context to this spu.
741 *
742 * Should be called with ctx->state_mutex held.
743 */
744static void spu_unschedule(struct spu *spu, struct spu_context *ctx,
745 int free_spu)
746{
747 int node = spu->node;
748
749 mutex_lock(&cbe_spu_info[node].list_mutex);
750 cbe_spu_info[node].nr_active--;
751 if (free_spu)
752 spu->alloc_state = SPU_FREE;
753 spu_unbind_context(spu, ctx);
754 ctx->stats.invol_ctx_switch++;
755 spu->stats.invol_ctx_switch++;
756 mutex_unlock(&cbe_spu_info[node].list_mutex);
757}
758
759/**
760 * spu_activate - find a free spu for a context and execute it
761 * @ctx: spu context to schedule
762 * @flags: flags (currently ignored)
763 *
764 * Tries to find a free spu to run @ctx. If no free spu is available
765 * add the context to the runqueue so it gets woken up once an spu
766 * is available.
767 */
768int spu_activate(struct spu_context *ctx, unsigned long flags)
769{
770 struct spu *spu;
771
772 /*
773 * If there are multiple threads waiting for a single context
774 * only one actually binds the context while the others will
775 * only be able to acquire the state_mutex once the context
776 * already is in runnable state.
777 */
778 if (ctx->spu)
779 return 0;
780
781spu_activate_top:
782 if (signal_pending(current))
783 return -ERESTARTSYS;
784
785 spu = spu_get_idle(ctx);
786 /*
787 * If this is a realtime thread we try to get it running by
788 * preempting a lower priority thread.
789 */
790 if (!spu && rt_prio(ctx->prio))
791 spu = find_victim(ctx);
792 if (spu) {
793 unsigned long runcntl;
794
795 runcntl = ctx->ops->runcntl_read(ctx);
796 __spu_schedule(spu, ctx);
797 if (runcntl & SPU_RUNCNTL_RUNNABLE)
798 spuctx_switch_state(ctx, SPU_UTIL_USER);
799
800 return 0;
801 }
802
803 if (ctx->flags & SPU_CREATE_NOSCHED) {
804 spu_prio_wait(ctx);
805 goto spu_activate_top;
806 }
807
808 spu_add_to_rq(ctx);
809
810 return 0;
811}
812
813/**
814 * grab_runnable_context - try to find a runnable context
815 *
816 * Remove the highest priority context on the runqueue and return it
817 * to the caller. Returns %NULL if no runnable context was found.
818 */
819static struct spu_context *grab_runnable_context(int prio, int node)
820{
821 struct spu_context *ctx;
822 int best;
823
824 spin_lock(&spu_prio->runq_lock);
825 best = find_first_bit(spu_prio->bitmap, prio);
826 while (best < prio) {
827 struct list_head *rq = &spu_prio->runq[best];
828
829 list_for_each_entry(ctx, rq, rq) {
830 /* XXX(hch): check for affinity here as well */
831 if (__node_allowed(ctx, node)) {
832 __spu_del_from_rq(ctx);
833 goto found;
834 }
835 }
836 best++;
837 }
838 ctx = NULL;
839 found:
840 spin_unlock(&spu_prio->runq_lock);
841 return ctx;
842}
843
844static int __spu_deactivate(struct spu_context *ctx, int force, int max_prio)
845{
846 struct spu *spu = ctx->spu;
847 struct spu_context *new = NULL;
848
849 if (spu) {
850 new = grab_runnable_context(max_prio, spu->node);
851 if (new || force) {
852 spu_unschedule(spu, ctx, new == NULL);
853 if (new) {
854 if (new->flags & SPU_CREATE_NOSCHED)
855 wake_up(&new->stop_wq);
856 else {
857 spu_release(ctx);
858 spu_schedule(spu, new);
859 /* this one can't easily be made
860 interruptible */
861 mutex_lock(&ctx->state_mutex);
862 }
863 }
864 }
865 }
866
867 return new != NULL;
868}
869
870/**
871 * spu_deactivate - unbind a context from it's physical spu
872 * @ctx: spu context to unbind
873 *
874 * Unbind @ctx from the physical spu it is running on and schedule
875 * the highest priority context to run on the freed physical spu.
876 */
877void spu_deactivate(struct spu_context *ctx)
878{
879 spu_context_nospu_trace(spu_deactivate__enter, ctx);
880 __spu_deactivate(ctx, 1, MAX_PRIO);
881}
882
883/**
884 * spu_yield - yield a physical spu if others are waiting
885 * @ctx: spu context to yield
886 *
887 * Check if there is a higher priority context waiting and if yes
888 * unbind @ctx from the physical spu and schedule the highest
889 * priority context to run on the freed physical spu instead.
890 */
891void spu_yield(struct spu_context *ctx)
892{
893 spu_context_nospu_trace(spu_yield__enter, ctx);
894 if (!(ctx->flags & SPU_CREATE_NOSCHED)) {
895 mutex_lock(&ctx->state_mutex);
896 __spu_deactivate(ctx, 0, MAX_PRIO);
897 mutex_unlock(&ctx->state_mutex);
898 }
899}
900
901static noinline void spusched_tick(struct spu_context *ctx)
902{
903 struct spu_context *new = NULL;
904 struct spu *spu = NULL;
905
906 if (spu_acquire(ctx))
907 BUG(); /* a kernel thread never has signals pending */
908
909 if (ctx->state != SPU_STATE_RUNNABLE)
910 goto out;
911 if (ctx->flags & SPU_CREATE_NOSCHED)
912 goto out;
913 if (ctx->policy == SCHED_FIFO)
914 goto out;
915
916 if (--ctx->time_slice && test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
917 goto out;
918
919 spu = ctx->spu;
920
921 spu_context_trace(spusched_tick__preempt, ctx, spu);
922
923 new = grab_runnable_context(ctx->prio + 1, spu->node);
924 if (new) {
925 spu_unschedule(spu, ctx, 0);
926 if (test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
927 spu_add_to_rq(ctx);
928 } else {
929 spu_context_nospu_trace(spusched_tick__newslice, ctx);
930 if (!ctx->time_slice)
931 ctx->time_slice++;
932 }
933out:
934 spu_release(ctx);
935
936 if (new)
937 spu_schedule(spu, new);
938}
939
940/**
941 * count_active_contexts - count nr of active tasks
942 *
943 * Return the number of tasks currently running or waiting to run.
944 *
945 * Note that we don't take runq_lock / list_mutex here. Reading
946 * a single 32bit value is atomic on powerpc, and we don't care
947 * about memory ordering issues here.
948 */
949static unsigned long count_active_contexts(void)
950{
951 int nr_active = 0, node;
952
953 for (node = 0; node < MAX_NUMNODES; node++)
954 nr_active += cbe_spu_info[node].nr_active;
955 nr_active += spu_prio->nr_waiting;
956
957 return nr_active;
958}
959
960/**
961 * spu_calc_load - update the avenrun load estimates.
962 *
963 * No locking against reading these values from userspace, as for
964 * the CPU loadavg code.
965 */
966static void spu_calc_load(void)
967{
968 unsigned long active_tasks; /* fixed-point */
969
970 active_tasks = count_active_contexts() * FIXED_1;
971 spu_avenrun[0] = calc_load(spu_avenrun[0], EXP_1, active_tasks);
972 spu_avenrun[1] = calc_load(spu_avenrun[1], EXP_5, active_tasks);
973 spu_avenrun[2] = calc_load(spu_avenrun[2], EXP_15, active_tasks);
974}
975
976static void spusched_wake(struct timer_list *unused)
977{
978 mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
979 wake_up_process(spusched_task);
980}
981
982static void spuloadavg_wake(struct timer_list *unused)
983{
984 mod_timer(&spuloadavg_timer, jiffies + LOAD_FREQ);
985 spu_calc_load();
986}
987
988static int spusched_thread(void *unused)
989{
990 struct spu *spu;
991 int node;
992
993 while (!kthread_should_stop()) {
994 set_current_state(TASK_INTERRUPTIBLE);
995 schedule();
996 for (node = 0; node < MAX_NUMNODES; node++) {
997 struct mutex *mtx = &cbe_spu_info[node].list_mutex;
998
999 mutex_lock(mtx);
1000 list_for_each_entry(spu, &cbe_spu_info[node].spus,
1001 cbe_list) {
1002 struct spu_context *ctx = spu->ctx;
1003
1004 if (ctx) {
1005 get_spu_context(ctx);
1006 mutex_unlock(mtx);
1007 spusched_tick(ctx);
1008 mutex_lock(mtx);
1009 put_spu_context(ctx);
1010 }
1011 }
1012 mutex_unlock(mtx);
1013 }
1014 }
1015
1016 return 0;
1017}
1018
1019void spuctx_switch_state(struct spu_context *ctx,
1020 enum spu_utilization_state new_state)
1021{
1022 unsigned long long curtime;
1023 signed long long delta;
1024 struct spu *spu;
1025 enum spu_utilization_state old_state;
1026 int node;
1027
1028 curtime = ktime_get_ns();
1029 delta = curtime - ctx->stats.tstamp;
1030
1031 WARN_ON(!mutex_is_locked(&ctx->state_mutex));
1032 WARN_ON(delta < 0);
1033
1034 spu = ctx->spu;
1035 old_state = ctx->stats.util_state;
1036 ctx->stats.util_state = new_state;
1037 ctx->stats.tstamp = curtime;
1038
1039 /*
1040 * Update the physical SPU utilization statistics.
1041 */
1042 if (spu) {
1043 ctx->stats.times[old_state] += delta;
1044 spu->stats.times[old_state] += delta;
1045 spu->stats.util_state = new_state;
1046 spu->stats.tstamp = curtime;
1047 node = spu->node;
1048 if (old_state == SPU_UTIL_USER)
1049 atomic_dec(&cbe_spu_info[node].busy_spus);
1050 if (new_state == SPU_UTIL_USER)
1051 atomic_inc(&cbe_spu_info[node].busy_spus);
1052 }
1053}
1054
1055#ifdef CONFIG_PROC_FS
1056static int show_spu_loadavg(struct seq_file *s, void *private)
1057{
1058 int a, b, c;
1059
1060 a = spu_avenrun[0] + (FIXED_1/200);
1061 b = spu_avenrun[1] + (FIXED_1/200);
1062 c = spu_avenrun[2] + (FIXED_1/200);
1063
1064 /*
1065 * Note that last_pid doesn't really make much sense for the
1066 * SPU loadavg (it even seems very odd on the CPU side...),
1067 * but we include it here to have a 100% compatible interface.
1068 */
1069 seq_printf(s, "%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
1070 LOAD_INT(a), LOAD_FRAC(a),
1071 LOAD_INT(b), LOAD_FRAC(b),
1072 LOAD_INT(c), LOAD_FRAC(c),
1073 count_active_contexts(),
1074 atomic_read(&nr_spu_contexts),
1075 idr_get_cursor(&task_active_pid_ns(current)->idr) - 1);
1076 return 0;
1077}
1078#endif
1079
1080int __init spu_sched_init(void)
1081{
1082 struct proc_dir_entry *entry;
1083 int err = -ENOMEM, i;
1084
1085 spu_prio = kzalloc(sizeof(struct spu_prio_array), GFP_KERNEL);
1086 if (!spu_prio)
1087 goto out;
1088
1089 for (i = 0; i < MAX_PRIO; i++) {
1090 INIT_LIST_HEAD(&spu_prio->runq[i]);
1091 __clear_bit(i, spu_prio->bitmap);
1092 }
1093 spin_lock_init(&spu_prio->runq_lock);
1094
1095 timer_setup(&spusched_timer, spusched_wake, 0);
1096 timer_setup(&spuloadavg_timer, spuloadavg_wake, 0);
1097
1098 spusched_task = kthread_run(spusched_thread, NULL, "spusched");
1099 if (IS_ERR(spusched_task)) {
1100 err = PTR_ERR(spusched_task);
1101 goto out_free_spu_prio;
1102 }
1103
1104 mod_timer(&spuloadavg_timer, 0);
1105
1106 entry = proc_create_single("spu_loadavg", 0, NULL, show_spu_loadavg);
1107 if (!entry)
1108 goto out_stop_kthread;
1109
1110 pr_debug("spusched: tick: %d, min ticks: %d, default ticks: %d\n",
1111 SPUSCHED_TICK, MIN_SPU_TIMESLICE, DEF_SPU_TIMESLICE);
1112 return 0;
1113
1114 out_stop_kthread:
1115 kthread_stop(spusched_task);
1116 out_free_spu_prio:
1117 kfree(spu_prio);
1118 out:
1119 return err;
1120}
1121
1122void spu_sched_exit(void)
1123{
1124 struct spu *spu;
1125 int node;
1126
1127 remove_proc_entry("spu_loadavg", NULL);
1128
1129 del_timer_sync(&spusched_timer);
1130 del_timer_sync(&spuloadavg_timer);
1131 kthread_stop(spusched_task);
1132
1133 for (node = 0; node < MAX_NUMNODES; node++) {
1134 mutex_lock(&cbe_spu_info[node].list_mutex);
1135 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list)
1136 if (spu->alloc_state != SPU_FREE)
1137 spu->alloc_state = SPU_FREE;
1138 mutex_unlock(&cbe_spu_info[node].list_mutex);
1139 }
1140 kfree(spu_prio);
1141}
1/* sched.c - SPU scheduler.
2 *
3 * Copyright (C) IBM 2005
4 * Author: Mark Nutter <mnutter@us.ibm.com>
5 *
6 * 2006-03-31 NUMA domains added.
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2, or (at your option)
11 * any later version.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23#undef DEBUG
24
25#include <linux/errno.h>
26#include <linux/sched.h>
27#include <linux/sched/rt.h>
28#include <linux/kernel.h>
29#include <linux/mm.h>
30#include <linux/slab.h>
31#include <linux/completion.h>
32#include <linux/vmalloc.h>
33#include <linux/smp.h>
34#include <linux/stddef.h>
35#include <linux/unistd.h>
36#include <linux/numa.h>
37#include <linux/mutex.h>
38#include <linux/notifier.h>
39#include <linux/kthread.h>
40#include <linux/pid_namespace.h>
41#include <linux/proc_fs.h>
42#include <linux/seq_file.h>
43
44#include <asm/io.h>
45#include <asm/mmu_context.h>
46#include <asm/spu.h>
47#include <asm/spu_csa.h>
48#include <asm/spu_priv1.h>
49#include "spufs.h"
50#define CREATE_TRACE_POINTS
51#include "sputrace.h"
52
53struct spu_prio_array {
54 DECLARE_BITMAP(bitmap, MAX_PRIO);
55 struct list_head runq[MAX_PRIO];
56 spinlock_t runq_lock;
57 int nr_waiting;
58};
59
60static unsigned long spu_avenrun[3];
61static struct spu_prio_array *spu_prio;
62static struct task_struct *spusched_task;
63static struct timer_list spusched_timer;
64static struct timer_list spuloadavg_timer;
65
66/*
67 * Priority of a normal, non-rt, non-niced'd process (aka nice level 0).
68 */
69#define NORMAL_PRIO 120
70
71/*
72 * Frequency of the spu scheduler tick. By default we do one SPU scheduler
73 * tick for every 10 CPU scheduler ticks.
74 */
75#define SPUSCHED_TICK (10)
76
77/*
78 * These are the 'tuning knobs' of the scheduler:
79 *
80 * Minimum timeslice is 5 msecs (or 1 spu scheduler tick, whichever is
81 * larger), default timeslice is 100 msecs, maximum timeslice is 800 msecs.
82 */
83#define MIN_SPU_TIMESLICE max(5 * HZ / (1000 * SPUSCHED_TICK), 1)
84#define DEF_SPU_TIMESLICE (100 * HZ / (1000 * SPUSCHED_TICK))
85
86#define SCALE_PRIO(x, prio) \
87 max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_SPU_TIMESLICE)
88
89/*
90 * scale user-nice values [ -20 ... 0 ... 19 ] to time slice values:
91 * [800ms ... 100ms ... 5ms]
92 *
93 * The higher a thread's priority, the bigger timeslices
94 * it gets during one round of execution. But even the lowest
95 * priority thread gets MIN_TIMESLICE worth of execution time.
96 */
97void spu_set_timeslice(struct spu_context *ctx)
98{
99 if (ctx->prio < NORMAL_PRIO)
100 ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE * 4, ctx->prio);
101 else
102 ctx->time_slice = SCALE_PRIO(DEF_SPU_TIMESLICE, ctx->prio);
103}
104
105/*
106 * Update scheduling information from the owning thread.
107 */
108void __spu_update_sched_info(struct spu_context *ctx)
109{
110 /*
111 * assert that the context is not on the runqueue, so it is safe
112 * to change its scheduling parameters.
113 */
114 BUG_ON(!list_empty(&ctx->rq));
115
116 /*
117 * 32-Bit assignments are atomic on powerpc, and we don't care about
118 * memory ordering here because retrieving the controlling thread is
119 * per definition racy.
120 */
121 ctx->tid = current->pid;
122
123 /*
124 * We do our own priority calculations, so we normally want
125 * ->static_prio to start with. Unfortunately this field
126 * contains junk for threads with a realtime scheduling
127 * policy so we have to look at ->prio in this case.
128 */
129 if (rt_prio(current->prio))
130 ctx->prio = current->prio;
131 else
132 ctx->prio = current->static_prio;
133 ctx->policy = current->policy;
134
135 /*
136 * TO DO: the context may be loaded, so we may need to activate
137 * it again on a different node. But it shouldn't hurt anything
138 * to update its parameters, because we know that the scheduler
139 * is not actively looking at this field, since it is not on the
140 * runqueue. The context will be rescheduled on the proper node
141 * if it is timesliced or preempted.
142 */
143 cpumask_copy(&ctx->cpus_allowed, tsk_cpus_allowed(current));
144
145 /* Save the current cpu id for spu interrupt routing. */
146 ctx->last_ran = raw_smp_processor_id();
147}
148
149void spu_update_sched_info(struct spu_context *ctx)
150{
151 int node;
152
153 if (ctx->state == SPU_STATE_RUNNABLE) {
154 node = ctx->spu->node;
155
156 /*
157 * Take list_mutex to sync with find_victim().
158 */
159 mutex_lock(&cbe_spu_info[node].list_mutex);
160 __spu_update_sched_info(ctx);
161 mutex_unlock(&cbe_spu_info[node].list_mutex);
162 } else {
163 __spu_update_sched_info(ctx);
164 }
165}
166
167static int __node_allowed(struct spu_context *ctx, int node)
168{
169 if (nr_cpus_node(node)) {
170 const struct cpumask *mask = cpumask_of_node(node);
171
172 if (cpumask_intersects(mask, &ctx->cpus_allowed))
173 return 1;
174 }
175
176 return 0;
177}
178
179static int node_allowed(struct spu_context *ctx, int node)
180{
181 int rval;
182
183 spin_lock(&spu_prio->runq_lock);
184 rval = __node_allowed(ctx, node);
185 spin_unlock(&spu_prio->runq_lock);
186
187 return rval;
188}
189
190void do_notify_spus_active(void)
191{
192 int node;
193
194 /*
195 * Wake up the active spu_contexts.
196 *
197 * When the awakened processes see their "notify_active" flag is set,
198 * they will call spu_switch_notify().
199 */
200 for_each_online_node(node) {
201 struct spu *spu;
202
203 mutex_lock(&cbe_spu_info[node].list_mutex);
204 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
205 if (spu->alloc_state != SPU_FREE) {
206 struct spu_context *ctx = spu->ctx;
207 set_bit(SPU_SCHED_NOTIFY_ACTIVE,
208 &ctx->sched_flags);
209 mb();
210 wake_up_all(&ctx->stop_wq);
211 }
212 }
213 mutex_unlock(&cbe_spu_info[node].list_mutex);
214 }
215}
216
217/**
218 * spu_bind_context - bind spu context to physical spu
219 * @spu: physical spu to bind to
220 * @ctx: context to bind
221 */
222static void spu_bind_context(struct spu *spu, struct spu_context *ctx)
223{
224 spu_context_trace(spu_bind_context__enter, ctx, spu);
225
226 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
227
228 if (ctx->flags & SPU_CREATE_NOSCHED)
229 atomic_inc(&cbe_spu_info[spu->node].reserved_spus);
230
231 ctx->stats.slb_flt_base = spu->stats.slb_flt;
232 ctx->stats.class2_intr_base = spu->stats.class2_intr;
233
234 spu_associate_mm(spu, ctx->owner);
235
236 spin_lock_irq(&spu->register_lock);
237 spu->ctx = ctx;
238 spu->flags = 0;
239 ctx->spu = spu;
240 ctx->ops = &spu_hw_ops;
241 spu->pid = current->pid;
242 spu->tgid = current->tgid;
243 spu->ibox_callback = spufs_ibox_callback;
244 spu->wbox_callback = spufs_wbox_callback;
245 spu->stop_callback = spufs_stop_callback;
246 spu->mfc_callback = spufs_mfc_callback;
247 spin_unlock_irq(&spu->register_lock);
248
249 spu_unmap_mappings(ctx);
250
251 spu_switch_log_notify(spu, ctx, SWITCH_LOG_START, 0);
252 spu_restore(&ctx->csa, spu);
253 spu->timestamp = jiffies;
254 spu_switch_notify(spu, ctx);
255 ctx->state = SPU_STATE_RUNNABLE;
256
257 spuctx_switch_state(ctx, SPU_UTIL_USER);
258}
259
260/*
261 * Must be used with the list_mutex held.
262 */
263static inline int sched_spu(struct spu *spu)
264{
265 BUG_ON(!mutex_is_locked(&cbe_spu_info[spu->node].list_mutex));
266
267 return (!spu->ctx || !(spu->ctx->flags & SPU_CREATE_NOSCHED));
268}
269
270static void aff_merge_remaining_ctxs(struct spu_gang *gang)
271{
272 struct spu_context *ctx;
273
274 list_for_each_entry(ctx, &gang->aff_list_head, aff_list) {
275 if (list_empty(&ctx->aff_list))
276 list_add(&ctx->aff_list, &gang->aff_list_head);
277 }
278 gang->aff_flags |= AFF_MERGED;
279}
280
281static void aff_set_offsets(struct spu_gang *gang)
282{
283 struct spu_context *ctx;
284 int offset;
285
286 offset = -1;
287 list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
288 aff_list) {
289 if (&ctx->aff_list == &gang->aff_list_head)
290 break;
291 ctx->aff_offset = offset--;
292 }
293
294 offset = 0;
295 list_for_each_entry(ctx, gang->aff_ref_ctx->aff_list.prev, aff_list) {
296 if (&ctx->aff_list == &gang->aff_list_head)
297 break;
298 ctx->aff_offset = offset++;
299 }
300
301 gang->aff_flags |= AFF_OFFSETS_SET;
302}
303
304static struct spu *aff_ref_location(struct spu_context *ctx, int mem_aff,
305 int group_size, int lowest_offset)
306{
307 struct spu *spu;
308 int node, n;
309
310 /*
311 * TODO: A better algorithm could be used to find a good spu to be
312 * used as reference location for the ctxs chain.
313 */
314 node = cpu_to_node(raw_smp_processor_id());
315 for (n = 0; n < MAX_NUMNODES; n++, node++) {
316 /*
317 * "available_spus" counts how many spus are not potentially
318 * going to be used by other affinity gangs whose reference
319 * context is already in place. Although this code seeks to
320 * avoid having affinity gangs with a summed amount of
321 * contexts bigger than the amount of spus in the node,
322 * this may happen sporadically. In this case, available_spus
323 * becomes negative, which is harmless.
324 */
325 int available_spus;
326
327 node = (node < MAX_NUMNODES) ? node : 0;
328 if (!node_allowed(ctx, node))
329 continue;
330
331 available_spus = 0;
332 mutex_lock(&cbe_spu_info[node].list_mutex);
333 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
334 if (spu->ctx && spu->ctx->gang && !spu->ctx->aff_offset
335 && spu->ctx->gang->aff_ref_spu)
336 available_spus -= spu->ctx->gang->contexts;
337 available_spus++;
338 }
339 if (available_spus < ctx->gang->contexts) {
340 mutex_unlock(&cbe_spu_info[node].list_mutex);
341 continue;
342 }
343
344 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
345 if ((!mem_aff || spu->has_mem_affinity) &&
346 sched_spu(spu)) {
347 mutex_unlock(&cbe_spu_info[node].list_mutex);
348 return spu;
349 }
350 }
351 mutex_unlock(&cbe_spu_info[node].list_mutex);
352 }
353 return NULL;
354}
355
356static void aff_set_ref_point_location(struct spu_gang *gang)
357{
358 int mem_aff, gs, lowest_offset;
359 struct spu_context *ctx;
360 struct spu *tmp;
361
362 mem_aff = gang->aff_ref_ctx->flags & SPU_CREATE_AFFINITY_MEM;
363 lowest_offset = 0;
364 gs = 0;
365
366 list_for_each_entry(tmp, &gang->aff_list_head, aff_list)
367 gs++;
368
369 list_for_each_entry_reverse(ctx, &gang->aff_ref_ctx->aff_list,
370 aff_list) {
371 if (&ctx->aff_list == &gang->aff_list_head)
372 break;
373 lowest_offset = ctx->aff_offset;
374 }
375
376 gang->aff_ref_spu = aff_ref_location(gang->aff_ref_ctx, mem_aff, gs,
377 lowest_offset);
378}
379
380static struct spu *ctx_location(struct spu *ref, int offset, int node)
381{
382 struct spu *spu;
383
384 spu = NULL;
385 if (offset >= 0) {
386 list_for_each_entry(spu, ref->aff_list.prev, aff_list) {
387 BUG_ON(spu->node != node);
388 if (offset == 0)
389 break;
390 if (sched_spu(spu))
391 offset--;
392 }
393 } else {
394 list_for_each_entry_reverse(spu, ref->aff_list.next, aff_list) {
395 BUG_ON(spu->node != node);
396 if (offset == 0)
397 break;
398 if (sched_spu(spu))
399 offset++;
400 }
401 }
402
403 return spu;
404}
405
406/*
407 * affinity_check is called each time a context is going to be scheduled.
408 * It returns the spu ptr on which the context must run.
409 */
410static int has_affinity(struct spu_context *ctx)
411{
412 struct spu_gang *gang = ctx->gang;
413
414 if (list_empty(&ctx->aff_list))
415 return 0;
416
417 if (atomic_read(&ctx->gang->aff_sched_count) == 0)
418 ctx->gang->aff_ref_spu = NULL;
419
420 if (!gang->aff_ref_spu) {
421 if (!(gang->aff_flags & AFF_MERGED))
422 aff_merge_remaining_ctxs(gang);
423 if (!(gang->aff_flags & AFF_OFFSETS_SET))
424 aff_set_offsets(gang);
425 aff_set_ref_point_location(gang);
426 }
427
428 return gang->aff_ref_spu != NULL;
429}
430
431/**
432 * spu_unbind_context - unbind spu context from physical spu
433 * @spu: physical spu to unbind from
434 * @ctx: context to unbind
435 */
436static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
437{
438 u32 status;
439
440 spu_context_trace(spu_unbind_context__enter, ctx, spu);
441
442 spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
443
444 if (spu->ctx->flags & SPU_CREATE_NOSCHED)
445 atomic_dec(&cbe_spu_info[spu->node].reserved_spus);
446
447 if (ctx->gang)
448 /*
449 * If ctx->gang->aff_sched_count is positive, SPU affinity is
450 * being considered in this gang. Using atomic_dec_if_positive
451 * allow us to skip an explicit check for affinity in this gang
452 */
453 atomic_dec_if_positive(&ctx->gang->aff_sched_count);
454
455 spu_switch_notify(spu, NULL);
456 spu_unmap_mappings(ctx);
457 spu_save(&ctx->csa, spu);
458 spu_switch_log_notify(spu, ctx, SWITCH_LOG_STOP, 0);
459
460 spin_lock_irq(&spu->register_lock);
461 spu->timestamp = jiffies;
462 ctx->state = SPU_STATE_SAVED;
463 spu->ibox_callback = NULL;
464 spu->wbox_callback = NULL;
465 spu->stop_callback = NULL;
466 spu->mfc_callback = NULL;
467 spu->pid = 0;
468 spu->tgid = 0;
469 ctx->ops = &spu_backing_ops;
470 spu->flags = 0;
471 spu->ctx = NULL;
472 spin_unlock_irq(&spu->register_lock);
473
474 spu_associate_mm(spu, NULL);
475
476 ctx->stats.slb_flt +=
477 (spu->stats.slb_flt - ctx->stats.slb_flt_base);
478 ctx->stats.class2_intr +=
479 (spu->stats.class2_intr - ctx->stats.class2_intr_base);
480
481 /* This maps the underlying spu state to idle */
482 spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
483 ctx->spu = NULL;
484
485 if (spu_stopped(ctx, &status))
486 wake_up_all(&ctx->stop_wq);
487}
488
489/**
490 * spu_add_to_rq - add a context to the runqueue
491 * @ctx: context to add
492 */
493static void __spu_add_to_rq(struct spu_context *ctx)
494{
495 /*
496 * Unfortunately this code path can be called from multiple threads
497 * on behalf of a single context due to the way the problem state
498 * mmap support works.
499 *
500 * Fortunately we need to wake up all these threads at the same time
501 * and can simply skip the runqueue addition for every but the first
502 * thread getting into this codepath.
503 *
504 * It's still quite hacky, and long-term we should proxy all other
505 * threads through the owner thread so that spu_run is in control
506 * of all the scheduling activity for a given context.
507 */
508 if (list_empty(&ctx->rq)) {
509 list_add_tail(&ctx->rq, &spu_prio->runq[ctx->prio]);
510 set_bit(ctx->prio, spu_prio->bitmap);
511 if (!spu_prio->nr_waiting++)
512 mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
513 }
514}
515
516static void spu_add_to_rq(struct spu_context *ctx)
517{
518 spin_lock(&spu_prio->runq_lock);
519 __spu_add_to_rq(ctx);
520 spin_unlock(&spu_prio->runq_lock);
521}
522
523static void __spu_del_from_rq(struct spu_context *ctx)
524{
525 int prio = ctx->prio;
526
527 if (!list_empty(&ctx->rq)) {
528 if (!--spu_prio->nr_waiting)
529 del_timer(&spusched_timer);
530 list_del_init(&ctx->rq);
531
532 if (list_empty(&spu_prio->runq[prio]))
533 clear_bit(prio, spu_prio->bitmap);
534 }
535}
536
537void spu_del_from_rq(struct spu_context *ctx)
538{
539 spin_lock(&spu_prio->runq_lock);
540 __spu_del_from_rq(ctx);
541 spin_unlock(&spu_prio->runq_lock);
542}
543
544static void spu_prio_wait(struct spu_context *ctx)
545{
546 DEFINE_WAIT(wait);
547
548 /*
549 * The caller must explicitly wait for a context to be loaded
550 * if the nosched flag is set. If NOSCHED is not set, the caller
551 * queues the context and waits for an spu event or error.
552 */
553 BUG_ON(!(ctx->flags & SPU_CREATE_NOSCHED));
554
555 spin_lock(&spu_prio->runq_lock);
556 prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE);
557 if (!signal_pending(current)) {
558 __spu_add_to_rq(ctx);
559 spin_unlock(&spu_prio->runq_lock);
560 mutex_unlock(&ctx->state_mutex);
561 schedule();
562 mutex_lock(&ctx->state_mutex);
563 spin_lock(&spu_prio->runq_lock);
564 __spu_del_from_rq(ctx);
565 }
566 spin_unlock(&spu_prio->runq_lock);
567 __set_current_state(TASK_RUNNING);
568 remove_wait_queue(&ctx->stop_wq, &wait);
569}
570
571static struct spu *spu_get_idle(struct spu_context *ctx)
572{
573 struct spu *spu, *aff_ref_spu;
574 int node, n;
575
576 spu_context_nospu_trace(spu_get_idle__enter, ctx);
577
578 if (ctx->gang) {
579 mutex_lock(&ctx->gang->aff_mutex);
580 if (has_affinity(ctx)) {
581 aff_ref_spu = ctx->gang->aff_ref_spu;
582 atomic_inc(&ctx->gang->aff_sched_count);
583 mutex_unlock(&ctx->gang->aff_mutex);
584 node = aff_ref_spu->node;
585
586 mutex_lock(&cbe_spu_info[node].list_mutex);
587 spu = ctx_location(aff_ref_spu, ctx->aff_offset, node);
588 if (spu && spu->alloc_state == SPU_FREE)
589 goto found;
590 mutex_unlock(&cbe_spu_info[node].list_mutex);
591
592 atomic_dec(&ctx->gang->aff_sched_count);
593 goto not_found;
594 }
595 mutex_unlock(&ctx->gang->aff_mutex);
596 }
597 node = cpu_to_node(raw_smp_processor_id());
598 for (n = 0; n < MAX_NUMNODES; n++, node++) {
599 node = (node < MAX_NUMNODES) ? node : 0;
600 if (!node_allowed(ctx, node))
601 continue;
602
603 mutex_lock(&cbe_spu_info[node].list_mutex);
604 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
605 if (spu->alloc_state == SPU_FREE)
606 goto found;
607 }
608 mutex_unlock(&cbe_spu_info[node].list_mutex);
609 }
610
611 not_found:
612 spu_context_nospu_trace(spu_get_idle__not_found, ctx);
613 return NULL;
614
615 found:
616 spu->alloc_state = SPU_USED;
617 mutex_unlock(&cbe_spu_info[node].list_mutex);
618 spu_context_trace(spu_get_idle__found, ctx, spu);
619 spu_init_channels(spu);
620 return spu;
621}
622
623/**
624 * find_victim - find a lower priority context to preempt
625 * @ctx: canidate context for running
626 *
627 * Returns the freed physical spu to run the new context on.
628 */
629static struct spu *find_victim(struct spu_context *ctx)
630{
631 struct spu_context *victim = NULL;
632 struct spu *spu;
633 int node, n;
634
635 spu_context_nospu_trace(spu_find_victim__enter, ctx);
636
637 /*
638 * Look for a possible preemption candidate on the local node first.
639 * If there is no candidate look at the other nodes. This isn't
640 * exactly fair, but so far the whole spu scheduler tries to keep
641 * a strong node affinity. We might want to fine-tune this in
642 * the future.
643 */
644 restart:
645 node = cpu_to_node(raw_smp_processor_id());
646 for (n = 0; n < MAX_NUMNODES; n++, node++) {
647 node = (node < MAX_NUMNODES) ? node : 0;
648 if (!node_allowed(ctx, node))
649 continue;
650
651 mutex_lock(&cbe_spu_info[node].list_mutex);
652 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list) {
653 struct spu_context *tmp = spu->ctx;
654
655 if (tmp && tmp->prio > ctx->prio &&
656 !(tmp->flags & SPU_CREATE_NOSCHED) &&
657 (!victim || tmp->prio > victim->prio)) {
658 victim = spu->ctx;
659 }
660 }
661 if (victim)
662 get_spu_context(victim);
663 mutex_unlock(&cbe_spu_info[node].list_mutex);
664
665 if (victim) {
666 /*
667 * This nests ctx->state_mutex, but we always lock
668 * higher priority contexts before lower priority
669 * ones, so this is safe until we introduce
670 * priority inheritance schemes.
671 *
672 * XXX if the highest priority context is locked,
673 * this can loop a long time. Might be better to
674 * look at another context or give up after X retries.
675 */
676 if (!mutex_trylock(&victim->state_mutex)) {
677 put_spu_context(victim);
678 victim = NULL;
679 goto restart;
680 }
681
682 spu = victim->spu;
683 if (!spu || victim->prio <= ctx->prio) {
684 /*
685 * This race can happen because we've dropped
686 * the active list mutex. Not a problem, just
687 * restart the search.
688 */
689 mutex_unlock(&victim->state_mutex);
690 put_spu_context(victim);
691 victim = NULL;
692 goto restart;
693 }
694
695 spu_context_trace(__spu_deactivate__unload, ctx, spu);
696
697 mutex_lock(&cbe_spu_info[node].list_mutex);
698 cbe_spu_info[node].nr_active--;
699 spu_unbind_context(spu, victim);
700 mutex_unlock(&cbe_spu_info[node].list_mutex);
701
702 victim->stats.invol_ctx_switch++;
703 spu->stats.invol_ctx_switch++;
704 if (test_bit(SPU_SCHED_SPU_RUN, &victim->sched_flags))
705 spu_add_to_rq(victim);
706
707 mutex_unlock(&victim->state_mutex);
708 put_spu_context(victim);
709
710 return spu;
711 }
712 }
713
714 return NULL;
715}
716
717static void __spu_schedule(struct spu *spu, struct spu_context *ctx)
718{
719 int node = spu->node;
720 int success = 0;
721
722 spu_set_timeslice(ctx);
723
724 mutex_lock(&cbe_spu_info[node].list_mutex);
725 if (spu->ctx == NULL) {
726 spu_bind_context(spu, ctx);
727 cbe_spu_info[node].nr_active++;
728 spu->alloc_state = SPU_USED;
729 success = 1;
730 }
731 mutex_unlock(&cbe_spu_info[node].list_mutex);
732
733 if (success)
734 wake_up_all(&ctx->run_wq);
735 else
736 spu_add_to_rq(ctx);
737}
738
739static void spu_schedule(struct spu *spu, struct spu_context *ctx)
740{
741 /* not a candidate for interruptible because it's called either
742 from the scheduler thread or from spu_deactivate */
743 mutex_lock(&ctx->state_mutex);
744 if (ctx->state == SPU_STATE_SAVED)
745 __spu_schedule(spu, ctx);
746 spu_release(ctx);
747}
748
749/**
750 * spu_unschedule - remove a context from a spu, and possibly release it.
751 * @spu: The SPU to unschedule from
752 * @ctx: The context currently scheduled on the SPU
753 * @free_spu Whether to free the SPU for other contexts
754 *
755 * Unbinds the context @ctx from the SPU @spu. If @free_spu is non-zero, the
756 * SPU is made available for other contexts (ie, may be returned by
757 * spu_get_idle). If this is zero, the caller is expected to schedule another
758 * context to this spu.
759 *
760 * Should be called with ctx->state_mutex held.
761 */
762static void spu_unschedule(struct spu *spu, struct spu_context *ctx,
763 int free_spu)
764{
765 int node = spu->node;
766
767 mutex_lock(&cbe_spu_info[node].list_mutex);
768 cbe_spu_info[node].nr_active--;
769 if (free_spu)
770 spu->alloc_state = SPU_FREE;
771 spu_unbind_context(spu, ctx);
772 ctx->stats.invol_ctx_switch++;
773 spu->stats.invol_ctx_switch++;
774 mutex_unlock(&cbe_spu_info[node].list_mutex);
775}
776
777/**
778 * spu_activate - find a free spu for a context and execute it
779 * @ctx: spu context to schedule
780 * @flags: flags (currently ignored)
781 *
782 * Tries to find a free spu to run @ctx. If no free spu is available
783 * add the context to the runqueue so it gets woken up once an spu
784 * is available.
785 */
786int spu_activate(struct spu_context *ctx, unsigned long flags)
787{
788 struct spu *spu;
789
790 /*
791 * If there are multiple threads waiting for a single context
792 * only one actually binds the context while the others will
793 * only be able to acquire the state_mutex once the context
794 * already is in runnable state.
795 */
796 if (ctx->spu)
797 return 0;
798
799spu_activate_top:
800 if (signal_pending(current))
801 return -ERESTARTSYS;
802
803 spu = spu_get_idle(ctx);
804 /*
805 * If this is a realtime thread we try to get it running by
806 * preempting a lower priority thread.
807 */
808 if (!spu && rt_prio(ctx->prio))
809 spu = find_victim(ctx);
810 if (spu) {
811 unsigned long runcntl;
812
813 runcntl = ctx->ops->runcntl_read(ctx);
814 __spu_schedule(spu, ctx);
815 if (runcntl & SPU_RUNCNTL_RUNNABLE)
816 spuctx_switch_state(ctx, SPU_UTIL_USER);
817
818 return 0;
819 }
820
821 if (ctx->flags & SPU_CREATE_NOSCHED) {
822 spu_prio_wait(ctx);
823 goto spu_activate_top;
824 }
825
826 spu_add_to_rq(ctx);
827
828 return 0;
829}
830
831/**
832 * grab_runnable_context - try to find a runnable context
833 *
834 * Remove the highest priority context on the runqueue and return it
835 * to the caller. Returns %NULL if no runnable context was found.
836 */
837static struct spu_context *grab_runnable_context(int prio, int node)
838{
839 struct spu_context *ctx;
840 int best;
841
842 spin_lock(&spu_prio->runq_lock);
843 best = find_first_bit(spu_prio->bitmap, prio);
844 while (best < prio) {
845 struct list_head *rq = &spu_prio->runq[best];
846
847 list_for_each_entry(ctx, rq, rq) {
848 /* XXX(hch): check for affinity here as well */
849 if (__node_allowed(ctx, node)) {
850 __spu_del_from_rq(ctx);
851 goto found;
852 }
853 }
854 best++;
855 }
856 ctx = NULL;
857 found:
858 spin_unlock(&spu_prio->runq_lock);
859 return ctx;
860}
861
862static int __spu_deactivate(struct spu_context *ctx, int force, int max_prio)
863{
864 struct spu *spu = ctx->spu;
865 struct spu_context *new = NULL;
866
867 if (spu) {
868 new = grab_runnable_context(max_prio, spu->node);
869 if (new || force) {
870 spu_unschedule(spu, ctx, new == NULL);
871 if (new) {
872 if (new->flags & SPU_CREATE_NOSCHED)
873 wake_up(&new->stop_wq);
874 else {
875 spu_release(ctx);
876 spu_schedule(spu, new);
877 /* this one can't easily be made
878 interruptible */
879 mutex_lock(&ctx->state_mutex);
880 }
881 }
882 }
883 }
884
885 return new != NULL;
886}
887
888/**
889 * spu_deactivate - unbind a context from it's physical spu
890 * @ctx: spu context to unbind
891 *
892 * Unbind @ctx from the physical spu it is running on and schedule
893 * the highest priority context to run on the freed physical spu.
894 */
895void spu_deactivate(struct spu_context *ctx)
896{
897 spu_context_nospu_trace(spu_deactivate__enter, ctx);
898 __spu_deactivate(ctx, 1, MAX_PRIO);
899}
900
901/**
902 * spu_yield - yield a physical spu if others are waiting
903 * @ctx: spu context to yield
904 *
905 * Check if there is a higher priority context waiting and if yes
906 * unbind @ctx from the physical spu and schedule the highest
907 * priority context to run on the freed physical spu instead.
908 */
909void spu_yield(struct spu_context *ctx)
910{
911 spu_context_nospu_trace(spu_yield__enter, ctx);
912 if (!(ctx->flags & SPU_CREATE_NOSCHED)) {
913 mutex_lock(&ctx->state_mutex);
914 __spu_deactivate(ctx, 0, MAX_PRIO);
915 mutex_unlock(&ctx->state_mutex);
916 }
917}
918
919static noinline void spusched_tick(struct spu_context *ctx)
920{
921 struct spu_context *new = NULL;
922 struct spu *spu = NULL;
923
924 if (spu_acquire(ctx))
925 BUG(); /* a kernel thread never has signals pending */
926
927 if (ctx->state != SPU_STATE_RUNNABLE)
928 goto out;
929 if (ctx->flags & SPU_CREATE_NOSCHED)
930 goto out;
931 if (ctx->policy == SCHED_FIFO)
932 goto out;
933
934 if (--ctx->time_slice && test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
935 goto out;
936
937 spu = ctx->spu;
938
939 spu_context_trace(spusched_tick__preempt, ctx, spu);
940
941 new = grab_runnable_context(ctx->prio + 1, spu->node);
942 if (new) {
943 spu_unschedule(spu, ctx, 0);
944 if (test_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags))
945 spu_add_to_rq(ctx);
946 } else {
947 spu_context_nospu_trace(spusched_tick__newslice, ctx);
948 if (!ctx->time_slice)
949 ctx->time_slice++;
950 }
951out:
952 spu_release(ctx);
953
954 if (new)
955 spu_schedule(spu, new);
956}
957
958/**
959 * count_active_contexts - count nr of active tasks
960 *
961 * Return the number of tasks currently running or waiting to run.
962 *
963 * Note that we don't take runq_lock / list_mutex here. Reading
964 * a single 32bit value is atomic on powerpc, and we don't care
965 * about memory ordering issues here.
966 */
967static unsigned long count_active_contexts(void)
968{
969 int nr_active = 0, node;
970
971 for (node = 0; node < MAX_NUMNODES; node++)
972 nr_active += cbe_spu_info[node].nr_active;
973 nr_active += spu_prio->nr_waiting;
974
975 return nr_active;
976}
977
978/**
979 * spu_calc_load - update the avenrun load estimates.
980 *
981 * No locking against reading these values from userspace, as for
982 * the CPU loadavg code.
983 */
984static void spu_calc_load(void)
985{
986 unsigned long active_tasks; /* fixed-point */
987
988 active_tasks = count_active_contexts() * FIXED_1;
989 CALC_LOAD(spu_avenrun[0], EXP_1, active_tasks);
990 CALC_LOAD(spu_avenrun[1], EXP_5, active_tasks);
991 CALC_LOAD(spu_avenrun[2], EXP_15, active_tasks);
992}
993
994static void spusched_wake(unsigned long data)
995{
996 mod_timer(&spusched_timer, jiffies + SPUSCHED_TICK);
997 wake_up_process(spusched_task);
998}
999
1000static void spuloadavg_wake(unsigned long data)
1001{
1002 mod_timer(&spuloadavg_timer, jiffies + LOAD_FREQ);
1003 spu_calc_load();
1004}
1005
1006static int spusched_thread(void *unused)
1007{
1008 struct spu *spu;
1009 int node;
1010
1011 while (!kthread_should_stop()) {
1012 set_current_state(TASK_INTERRUPTIBLE);
1013 schedule();
1014 for (node = 0; node < MAX_NUMNODES; node++) {
1015 struct mutex *mtx = &cbe_spu_info[node].list_mutex;
1016
1017 mutex_lock(mtx);
1018 list_for_each_entry(spu, &cbe_spu_info[node].spus,
1019 cbe_list) {
1020 struct spu_context *ctx = spu->ctx;
1021
1022 if (ctx) {
1023 get_spu_context(ctx);
1024 mutex_unlock(mtx);
1025 spusched_tick(ctx);
1026 mutex_lock(mtx);
1027 put_spu_context(ctx);
1028 }
1029 }
1030 mutex_unlock(mtx);
1031 }
1032 }
1033
1034 return 0;
1035}
1036
1037void spuctx_switch_state(struct spu_context *ctx,
1038 enum spu_utilization_state new_state)
1039{
1040 unsigned long long curtime;
1041 signed long long delta;
1042 struct timespec ts;
1043 struct spu *spu;
1044 enum spu_utilization_state old_state;
1045 int node;
1046
1047 ktime_get_ts(&ts);
1048 curtime = timespec_to_ns(&ts);
1049 delta = curtime - ctx->stats.tstamp;
1050
1051 WARN_ON(!mutex_is_locked(&ctx->state_mutex));
1052 WARN_ON(delta < 0);
1053
1054 spu = ctx->spu;
1055 old_state = ctx->stats.util_state;
1056 ctx->stats.util_state = new_state;
1057 ctx->stats.tstamp = curtime;
1058
1059 /*
1060 * Update the physical SPU utilization statistics.
1061 */
1062 if (spu) {
1063 ctx->stats.times[old_state] += delta;
1064 spu->stats.times[old_state] += delta;
1065 spu->stats.util_state = new_state;
1066 spu->stats.tstamp = curtime;
1067 node = spu->node;
1068 if (old_state == SPU_UTIL_USER)
1069 atomic_dec(&cbe_spu_info[node].busy_spus);
1070 if (new_state == SPU_UTIL_USER)
1071 atomic_inc(&cbe_spu_info[node].busy_spus);
1072 }
1073}
1074
1075#define LOAD_INT(x) ((x) >> FSHIFT)
1076#define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
1077
1078static int show_spu_loadavg(struct seq_file *s, void *private)
1079{
1080 int a, b, c;
1081
1082 a = spu_avenrun[0] + (FIXED_1/200);
1083 b = spu_avenrun[1] + (FIXED_1/200);
1084 c = spu_avenrun[2] + (FIXED_1/200);
1085
1086 /*
1087 * Note that last_pid doesn't really make much sense for the
1088 * SPU loadavg (it even seems very odd on the CPU side...),
1089 * but we include it here to have a 100% compatible interface.
1090 */
1091 seq_printf(s, "%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
1092 LOAD_INT(a), LOAD_FRAC(a),
1093 LOAD_INT(b), LOAD_FRAC(b),
1094 LOAD_INT(c), LOAD_FRAC(c),
1095 count_active_contexts(),
1096 atomic_read(&nr_spu_contexts),
1097 task_active_pid_ns(current)->last_pid);
1098 return 0;
1099}
1100
1101static int spu_loadavg_open(struct inode *inode, struct file *file)
1102{
1103 return single_open(file, show_spu_loadavg, NULL);
1104}
1105
1106static const struct file_operations spu_loadavg_fops = {
1107 .open = spu_loadavg_open,
1108 .read = seq_read,
1109 .llseek = seq_lseek,
1110 .release = single_release,
1111};
1112
1113int __init spu_sched_init(void)
1114{
1115 struct proc_dir_entry *entry;
1116 int err = -ENOMEM, i;
1117
1118 spu_prio = kzalloc(sizeof(struct spu_prio_array), GFP_KERNEL);
1119 if (!spu_prio)
1120 goto out;
1121
1122 for (i = 0; i < MAX_PRIO; i++) {
1123 INIT_LIST_HEAD(&spu_prio->runq[i]);
1124 __clear_bit(i, spu_prio->bitmap);
1125 }
1126 spin_lock_init(&spu_prio->runq_lock);
1127
1128 setup_timer(&spusched_timer, spusched_wake, 0);
1129 setup_timer(&spuloadavg_timer, spuloadavg_wake, 0);
1130
1131 spusched_task = kthread_run(spusched_thread, NULL, "spusched");
1132 if (IS_ERR(spusched_task)) {
1133 err = PTR_ERR(spusched_task);
1134 goto out_free_spu_prio;
1135 }
1136
1137 mod_timer(&spuloadavg_timer, 0);
1138
1139 entry = proc_create("spu_loadavg", 0, NULL, &spu_loadavg_fops);
1140 if (!entry)
1141 goto out_stop_kthread;
1142
1143 pr_debug("spusched: tick: %d, min ticks: %d, default ticks: %d\n",
1144 SPUSCHED_TICK, MIN_SPU_TIMESLICE, DEF_SPU_TIMESLICE);
1145 return 0;
1146
1147 out_stop_kthread:
1148 kthread_stop(spusched_task);
1149 out_free_spu_prio:
1150 kfree(spu_prio);
1151 out:
1152 return err;
1153}
1154
1155void spu_sched_exit(void)
1156{
1157 struct spu *spu;
1158 int node;
1159
1160 remove_proc_entry("spu_loadavg", NULL);
1161
1162 del_timer_sync(&spusched_timer);
1163 del_timer_sync(&spuloadavg_timer);
1164 kthread_stop(spusched_task);
1165
1166 for (node = 0; node < MAX_NUMNODES; node++) {
1167 mutex_lock(&cbe_spu_info[node].list_mutex);
1168 list_for_each_entry(spu, &cbe_spu_info[node].spus, cbe_list)
1169 if (spu->alloc_state != SPU_FREE)
1170 spu->alloc_state = SPU_FREE;
1171 mutex_unlock(&cbe_spu_info[node].list_mutex);
1172 }
1173 kfree(spu_prio);
1174}