1 /* sched.c - SPU scheduler.
3 * Copyright (C) IBM 2005
4 * Author: Mark Nutter <mnutter@us.ibm.com>
6 * 2006-03-31 NUMA domains added.
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)
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.
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.
25 #include <linux/errno.h>
26 #include <linux/sched.h>
27 #include <linux/sched/rt.h>
28 #include <linux/kernel.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>
45 #include <asm/mmu_context.h>
47 #include <asm/spu_csa.h>
48 #include <asm/spu_priv1.h>
50 #define CREATE_TRACE_POINTS
53 struct spu_prio_array
{
54 DECLARE_BITMAP(bitmap
, MAX_PRIO
);
55 struct list_head runq
[MAX_PRIO
];
60 static unsigned long spu_avenrun
[3];
61 static struct spu_prio_array
*spu_prio
;
62 static struct task_struct
*spusched_task
;
63 static struct timer_list spusched_timer
;
64 static struct timer_list spuloadavg_timer
;
67 * Priority of a normal, non-rt, non-niced'd process (aka nice level 0).
69 #define NORMAL_PRIO 120
72 * Frequency of the spu scheduler tick. By default we do one SPU scheduler
73 * tick for every 10 CPU scheduler ticks.
75 #define SPUSCHED_TICK (10)
78 * These are the 'tuning knobs' of the scheduler:
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.
83 #define MIN_SPU_TIMESLICE max(5 * HZ / (1000 * SPUSCHED_TICK), 1)
84 #define DEF_SPU_TIMESLICE (100 * HZ / (1000 * SPUSCHED_TICK))
86 #define SCALE_PRIO(x, prio) \
87 max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_SPU_TIMESLICE)
90 * scale user-nice values [ -20 ... 0 ... 19 ] to time slice values:
91 * [800ms ... 100ms ... 5ms]
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.
97 void spu_set_timeslice(struct spu_context
*ctx
)
99 if (ctx
->prio
< NORMAL_PRIO
)
100 ctx
->time_slice
= SCALE_PRIO(DEF_SPU_TIMESLICE
* 4, ctx
->prio
);
102 ctx
->time_slice
= SCALE_PRIO(DEF_SPU_TIMESLICE
, ctx
->prio
);
106 * Update scheduling information from the owning thread.
108 void __spu_update_sched_info(struct spu_context
*ctx
)
111 * assert that the context is not on the runqueue, so it is safe
112 * to change its scheduling parameters.
114 BUG_ON(!list_empty(&ctx
->rq
));
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.
121 ctx
->tid
= current
->pid
;
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.
129 if (rt_prio(current
->prio
))
130 ctx
->prio
= current
->prio
;
132 ctx
->prio
= current
->static_prio
;
133 ctx
->policy
= current
->policy
;
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.
143 cpumask_copy(&ctx
->cpus_allowed
, tsk_cpus_allowed(current
));
145 /* Save the current cpu id for spu interrupt routing. */
146 ctx
->last_ran
= raw_smp_processor_id();
149 void spu_update_sched_info(struct spu_context
*ctx
)
153 if (ctx
->state
== SPU_STATE_RUNNABLE
) {
154 node
= ctx
->spu
->node
;
157 * Take list_mutex to sync with find_victim().
159 mutex_lock(&cbe_spu_info
[node
].list_mutex
);
160 __spu_update_sched_info(ctx
);
161 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);
163 __spu_update_sched_info(ctx
);
167 static int __node_allowed(struct spu_context
*ctx
, int node
)
169 if (nr_cpus_node(node
)) {
170 const struct cpumask
*mask
= cpumask_of_node(node
);
172 if (cpumask_intersects(mask
, &ctx
->cpus_allowed
))
179 static int node_allowed(struct spu_context
*ctx
, int node
)
183 spin_lock(&spu_prio
->runq_lock
);
184 rval
= __node_allowed(ctx
, node
);
185 spin_unlock(&spu_prio
->runq_lock
);
190 void do_notify_spus_active(void)
195 * Wake up the active spu_contexts.
197 * When the awakened processes see their "notify_active" flag is set,
198 * they will call spu_switch_notify().
200 for_each_online_node(node
) {
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
,
210 wake_up_all(&ctx
->stop_wq
);
213 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);
218 * spu_bind_context - bind spu context to physical spu
219 * @spu: physical spu to bind to
220 * @ctx: context to bind
222 static void spu_bind_context(struct spu
*spu
, struct spu_context
*ctx
)
224 spu_context_trace(spu_bind_context__enter
, ctx
, spu
);
226 spuctx_switch_state(ctx
, SPU_UTIL_SYSTEM
);
228 if (ctx
->flags
& SPU_CREATE_NOSCHED
)
229 atomic_inc(&cbe_spu_info
[spu
->node
].reserved_spus
);
231 ctx
->stats
.slb_flt_base
= spu
->stats
.slb_flt
;
232 ctx
->stats
.class2_intr_base
= spu
->stats
.class2_intr
;
234 spu_associate_mm(spu
, ctx
->owner
);
236 spin_lock_irq(&spu
->register_lock
);
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
);
249 spu_unmap_mappings(ctx
);
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
;
257 spuctx_switch_state(ctx
, SPU_UTIL_USER
);
261 * Must be used with the list_mutex held.
263 static inline int sched_spu(struct spu
*spu
)
265 BUG_ON(!mutex_is_locked(&cbe_spu_info
[spu
->node
].list_mutex
));
267 return (!spu
->ctx
|| !(spu
->ctx
->flags
& SPU_CREATE_NOSCHED
));
270 static void aff_merge_remaining_ctxs(struct spu_gang
*gang
)
272 struct spu_context
*ctx
;
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
);
278 gang
->aff_flags
|= AFF_MERGED
;
281 static void aff_set_offsets(struct spu_gang
*gang
)
283 struct spu_context
*ctx
;
287 list_for_each_entry_reverse(ctx
, &gang
->aff_ref_ctx
->aff_list
,
289 if (&ctx
->aff_list
== &gang
->aff_list_head
)
291 ctx
->aff_offset
= offset
--;
295 list_for_each_entry(ctx
, gang
->aff_ref_ctx
->aff_list
.prev
, aff_list
) {
296 if (&ctx
->aff_list
== &gang
->aff_list_head
)
298 ctx
->aff_offset
= offset
++;
301 gang
->aff_flags
|= AFF_OFFSETS_SET
;
304 static struct spu
*aff_ref_location(struct spu_context
*ctx
, int mem_aff
,
305 int group_size
, int lowest_offset
)
311 * TODO: A better algorithm could be used to find a good spu to be
312 * used as reference location for the ctxs chain.
314 node
= cpu_to_node(raw_smp_processor_id());
315 for (n
= 0; n
< MAX_NUMNODES
; n
++, node
++) {
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.
327 node
= (node
< MAX_NUMNODES
) ? node
: 0;
328 if (!node_allowed(ctx
, node
))
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
;
339 if (available_spus
< ctx
->gang
->contexts
) {
340 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);
344 list_for_each_entry(spu
, &cbe_spu_info
[node
].spus
, cbe_list
) {
345 if ((!mem_aff
|| spu
->has_mem_affinity
) &&
347 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);
351 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);
356 static void aff_set_ref_point_location(struct spu_gang
*gang
)
358 int mem_aff
, gs
, lowest_offset
;
359 struct spu_context
*ctx
;
362 mem_aff
= gang
->aff_ref_ctx
->flags
& SPU_CREATE_AFFINITY_MEM
;
366 list_for_each_entry(tmp
, &gang
->aff_list_head
, aff_list
)
369 list_for_each_entry_reverse(ctx
, &gang
->aff_ref_ctx
->aff_list
,
371 if (&ctx
->aff_list
== &gang
->aff_list_head
)
373 lowest_offset
= ctx
->aff_offset
;
376 gang
->aff_ref_spu
= aff_ref_location(gang
->aff_ref_ctx
, mem_aff
, gs
,
380 static struct spu
*ctx_location(struct spu
*ref
, int offset
, int node
)
386 list_for_each_entry(spu
, ref
->aff_list
.prev
, aff_list
) {
387 BUG_ON(spu
->node
!= node
);
394 list_for_each_entry_reverse(spu
, ref
->aff_list
.next
, aff_list
) {
395 BUG_ON(spu
->node
!= node
);
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.
410 static int has_affinity(struct spu_context
*ctx
)
412 struct spu_gang
*gang
= ctx
->gang
;
414 if (list_empty(&ctx
->aff_list
))
417 if (atomic_read(&ctx
->gang
->aff_sched_count
) == 0)
418 ctx
->gang
->aff_ref_spu
= NULL
;
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
);
428 return gang
->aff_ref_spu
!= NULL
;
432 * spu_unbind_context - unbind spu context from physical spu
433 * @spu: physical spu to unbind from
434 * @ctx: context to unbind
436 static void spu_unbind_context(struct spu
*spu
, struct spu_context
*ctx
)
440 spu_context_trace(spu_unbind_context__enter
, ctx
, spu
);
442 spuctx_switch_state(ctx
, SPU_UTIL_SYSTEM
);
444 if (spu
->ctx
->flags
& SPU_CREATE_NOSCHED
)
445 atomic_dec(&cbe_spu_info
[spu
->node
].reserved_spus
);
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
453 atomic_dec_if_positive(&ctx
->gang
->aff_sched_count
);
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);
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
;
469 ctx
->ops
= &spu_backing_ops
;
472 spin_unlock_irq(&spu
->register_lock
);
474 spu_associate_mm(spu
, NULL
);
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
);
481 /* This maps the underlying spu state to idle */
482 spuctx_switch_state(ctx
, SPU_UTIL_IDLE_LOADED
);
485 if (spu_stopped(ctx
, &status
))
486 wake_up_all(&ctx
->stop_wq
);
490 * spu_add_to_rq - add a context to the runqueue
491 * @ctx: context to add
493 static void __spu_add_to_rq(struct spu_context
*ctx
)
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.
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.
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.
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
);
516 static void spu_add_to_rq(struct spu_context
*ctx
)
518 spin_lock(&spu_prio
->runq_lock
);
519 __spu_add_to_rq(ctx
);
520 spin_unlock(&spu_prio
->runq_lock
);
523 static void __spu_del_from_rq(struct spu_context
*ctx
)
525 int prio
= ctx
->prio
;
527 if (!list_empty(&ctx
->rq
)) {
528 if (!--spu_prio
->nr_waiting
)
529 del_timer(&spusched_timer
);
530 list_del_init(&ctx
->rq
);
532 if (list_empty(&spu_prio
->runq
[prio
]))
533 clear_bit(prio
, spu_prio
->bitmap
);
537 void spu_del_from_rq(struct spu_context
*ctx
)
539 spin_lock(&spu_prio
->runq_lock
);
540 __spu_del_from_rq(ctx
);
541 spin_unlock(&spu_prio
->runq_lock
);
544 static void spu_prio_wait(struct spu_context
*ctx
)
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.
553 BUG_ON(!(ctx
->flags
& SPU_CREATE_NOSCHED
));
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
);
562 mutex_lock(&ctx
->state_mutex
);
563 spin_lock(&spu_prio
->runq_lock
);
564 __spu_del_from_rq(ctx
);
566 spin_unlock(&spu_prio
->runq_lock
);
567 __set_current_state(TASK_RUNNING
);
568 remove_wait_queue(&ctx
->stop_wq
, &wait
);
571 static struct spu
*spu_get_idle(struct spu_context
*ctx
)
573 struct spu
*spu
, *aff_ref_spu
;
576 spu_context_nospu_trace(spu_get_idle__enter
, ctx
);
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
;
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
)
590 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);
592 atomic_dec(&ctx
->gang
->aff_sched_count
);
595 mutex_unlock(&ctx
->gang
->aff_mutex
);
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
))
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
)
608 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);
612 spu_context_nospu_trace(spu_get_idle__not_found
, ctx
);
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
);
624 * find_victim - find a lower priority context to preempt
625 * @ctx: canidate context for running
627 * Returns the freed physical spu to run the new context on.
629 static struct spu
*find_victim(struct spu_context
*ctx
)
631 struct spu_context
*victim
= NULL
;
635 spu_context_nospu_trace(spu_find_victim__enter
, ctx
);
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
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
))
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
;
655 if (tmp
&& tmp
->prio
> ctx
->prio
&&
656 !(tmp
->flags
& SPU_CREATE_NOSCHED
) &&
657 (!victim
|| tmp
->prio
> victim
->prio
)) {
662 get_spu_context(victim
);
663 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);
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.
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.
676 if (!mutex_trylock(&victim
->state_mutex
)) {
677 put_spu_context(victim
);
683 if (!spu
|| victim
->prio
<= ctx
->prio
) {
685 * This race can happen because we've dropped
686 * the active list mutex. Not a problem, just
687 * restart the search.
689 mutex_unlock(&victim
->state_mutex
);
690 put_spu_context(victim
);
695 spu_context_trace(__spu_deactivate__unload
, ctx
, spu
);
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
);
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
);
707 mutex_unlock(&victim
->state_mutex
);
708 put_spu_context(victim
);
717 static void __spu_schedule(struct spu
*spu
, struct spu_context
*ctx
)
719 int node
= spu
->node
;
722 spu_set_timeslice(ctx
);
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
;
731 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);
734 wake_up_all(&ctx
->run_wq
);
739 static void spu_schedule(struct spu
*spu
, struct spu_context
*ctx
)
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
);
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
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.
760 * Should be called with ctx->state_mutex held.
762 static void spu_unschedule(struct spu
*spu
, struct spu_context
*ctx
,
765 int node
= spu
->node
;
767 mutex_lock(&cbe_spu_info
[node
].list_mutex
);
768 cbe_spu_info
[node
].nr_active
--;
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
);
778 * spu_activate - find a free spu for a context and execute it
779 * @ctx: spu context to schedule
780 * @flags: flags (currently ignored)
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
786 int spu_activate(struct spu_context
*ctx
, unsigned long flags
)
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.
800 if (signal_pending(current
))
803 spu
= spu_get_idle(ctx
);
805 * If this is a realtime thread we try to get it running by
806 * preempting a lower priority thread.
808 if (!spu
&& rt_prio(ctx
->prio
))
809 spu
= find_victim(ctx
);
811 unsigned long runcntl
;
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
);
821 if (ctx
->flags
& SPU_CREATE_NOSCHED
) {
823 goto spu_activate_top
;
832 * grab_runnable_context - try to find a runnable context
834 * Remove the highest priority context on the runqueue and return it
835 * to the caller. Returns %NULL if no runnable context was found.
837 static struct spu_context
*grab_runnable_context(int prio
, int node
)
839 struct spu_context
*ctx
;
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
];
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
);
858 spin_unlock(&spu_prio
->runq_lock
);
862 static int __spu_deactivate(struct spu_context
*ctx
, int force
, int max_prio
)
864 struct spu
*spu
= ctx
->spu
;
865 struct spu_context
*new = NULL
;
868 new = grab_runnable_context(max_prio
, spu
->node
);
870 spu_unschedule(spu
, ctx
, new == NULL
);
872 if (new->flags
& SPU_CREATE_NOSCHED
)
873 wake_up(&new->stop_wq
);
876 spu_schedule(spu
, new);
877 /* this one can't easily be made
879 mutex_lock(&ctx
->state_mutex
);
889 * spu_deactivate - unbind a context from it's physical spu
890 * @ctx: spu context to unbind
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.
895 void spu_deactivate(struct spu_context
*ctx
)
897 spu_context_nospu_trace(spu_deactivate__enter
, ctx
);
898 __spu_deactivate(ctx
, 1, MAX_PRIO
);
902 * spu_yield - yield a physical spu if others are waiting
903 * @ctx: spu context to yield
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.
909 void spu_yield(struct spu_context
*ctx
)
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
);
919 static noinline
void spusched_tick(struct spu_context
*ctx
)
921 struct spu_context
*new = NULL
;
922 struct spu
*spu
= NULL
;
924 if (spu_acquire(ctx
))
925 BUG(); /* a kernel thread never has signals pending */
927 if (ctx
->state
!= SPU_STATE_RUNNABLE
)
929 if (ctx
->flags
& SPU_CREATE_NOSCHED
)
931 if (ctx
->policy
== SCHED_FIFO
)
934 if (--ctx
->time_slice
&& test_bit(SPU_SCHED_SPU_RUN
, &ctx
->sched_flags
))
939 spu_context_trace(spusched_tick__preempt
, ctx
, spu
);
941 new = grab_runnable_context(ctx
->prio
+ 1, spu
->node
);
943 spu_unschedule(spu
, ctx
, 0);
944 if (test_bit(SPU_SCHED_SPU_RUN
, &ctx
->sched_flags
))
947 spu_context_nospu_trace(spusched_tick__newslice
, ctx
);
948 if (!ctx
->time_slice
)
955 spu_schedule(spu
, new);
959 * count_active_contexts - count nr of active tasks
961 * Return the number of tasks currently running or waiting to run.
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.
967 static unsigned long count_active_contexts(void)
969 int nr_active
= 0, node
;
971 for (node
= 0; node
< MAX_NUMNODES
; node
++)
972 nr_active
+= cbe_spu_info
[node
].nr_active
;
973 nr_active
+= spu_prio
->nr_waiting
;
979 * spu_calc_load - update the avenrun load estimates.
981 * No locking against reading these values from userspace, as for
982 * the CPU loadavg code.
984 static void spu_calc_load(void)
986 unsigned long active_tasks
; /* fixed-point */
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
);
994 static void spusched_wake(unsigned long data
)
996 mod_timer(&spusched_timer
, jiffies
+ SPUSCHED_TICK
);
997 wake_up_process(spusched_task
);
1000 static void spuloadavg_wake(unsigned long data
)
1002 mod_timer(&spuloadavg_timer
, jiffies
+ LOAD_FREQ
);
1006 static int spusched_thread(void *unused
)
1011 while (!kthread_should_stop()) {
1012 set_current_state(TASK_INTERRUPTIBLE
);
1014 for (node
= 0; node
< MAX_NUMNODES
; node
++) {
1015 struct mutex
*mtx
= &cbe_spu_info
[node
].list_mutex
;
1018 list_for_each_entry(spu
, &cbe_spu_info
[node
].spus
,
1020 struct spu_context
*ctx
= spu
->ctx
;
1023 get_spu_context(ctx
);
1027 put_spu_context(ctx
);
1037 void spuctx_switch_state(struct spu_context
*ctx
,
1038 enum spu_utilization_state new_state
)
1040 unsigned long long curtime
;
1041 signed long long delta
;
1043 enum spu_utilization_state old_state
;
1046 curtime
= ktime_get_ns();
1047 delta
= curtime
- ctx
->stats
.tstamp
;
1049 WARN_ON(!mutex_is_locked(&ctx
->state_mutex
));
1053 old_state
= ctx
->stats
.util_state
;
1054 ctx
->stats
.util_state
= new_state
;
1055 ctx
->stats
.tstamp
= curtime
;
1058 * Update the physical SPU utilization statistics.
1061 ctx
->stats
.times
[old_state
] += delta
;
1062 spu
->stats
.times
[old_state
] += delta
;
1063 spu
->stats
.util_state
= new_state
;
1064 spu
->stats
.tstamp
= curtime
;
1066 if (old_state
== SPU_UTIL_USER
)
1067 atomic_dec(&cbe_spu_info
[node
].busy_spus
);
1068 if (new_state
== SPU_UTIL_USER
)
1069 atomic_inc(&cbe_spu_info
[node
].busy_spus
);
1073 #define LOAD_INT(x) ((x) >> FSHIFT)
1074 #define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
1076 static int show_spu_loadavg(struct seq_file
*s
, void *private)
1080 a
= spu_avenrun
[0] + (FIXED_1
/200);
1081 b
= spu_avenrun
[1] + (FIXED_1
/200);
1082 c
= spu_avenrun
[2] + (FIXED_1
/200);
1085 * Note that last_pid doesn't really make much sense for the
1086 * SPU loadavg (it even seems very odd on the CPU side...),
1087 * but we include it here to have a 100% compatible interface.
1089 seq_printf(s
, "%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
1090 LOAD_INT(a
), LOAD_FRAC(a
),
1091 LOAD_INT(b
), LOAD_FRAC(b
),
1092 LOAD_INT(c
), LOAD_FRAC(c
),
1093 count_active_contexts(),
1094 atomic_read(&nr_spu_contexts
),
1095 task_active_pid_ns(current
)->last_pid
);
1099 static int spu_loadavg_open(struct inode
*inode
, struct file
*file
)
1101 return single_open(file
, show_spu_loadavg
, NULL
);
1104 static const struct file_operations spu_loadavg_fops
= {
1105 .open
= spu_loadavg_open
,
1107 .llseek
= seq_lseek
,
1108 .release
= single_release
,
1111 int __init
spu_sched_init(void)
1113 struct proc_dir_entry
*entry
;
1114 int err
= -ENOMEM
, i
;
1116 spu_prio
= kzalloc(sizeof(struct spu_prio_array
), GFP_KERNEL
);
1120 for (i
= 0; i
< MAX_PRIO
; i
++) {
1121 INIT_LIST_HEAD(&spu_prio
->runq
[i
]);
1122 __clear_bit(i
, spu_prio
->bitmap
);
1124 spin_lock_init(&spu_prio
->runq_lock
);
1126 setup_timer(&spusched_timer
, spusched_wake
, 0);
1127 setup_timer(&spuloadavg_timer
, spuloadavg_wake
, 0);
1129 spusched_task
= kthread_run(spusched_thread
, NULL
, "spusched");
1130 if (IS_ERR(spusched_task
)) {
1131 err
= PTR_ERR(spusched_task
);
1132 goto out_free_spu_prio
;
1135 mod_timer(&spuloadavg_timer
, 0);
1137 entry
= proc_create("spu_loadavg", 0, NULL
, &spu_loadavg_fops
);
1139 goto out_stop_kthread
;
1141 pr_debug("spusched: tick: %d, min ticks: %d, default ticks: %d\n",
1142 SPUSCHED_TICK
, MIN_SPU_TIMESLICE
, DEF_SPU_TIMESLICE
);
1146 kthread_stop(spusched_task
);
1153 void spu_sched_exit(void)
1158 remove_proc_entry("spu_loadavg", NULL
);
1160 del_timer_sync(&spusched_timer
);
1161 del_timer_sync(&spuloadavg_timer
);
1162 kthread_stop(spusched_task
);
1164 for (node
= 0; node
< MAX_NUMNODES
; node
++) {
1165 mutex_lock(&cbe_spu_info
[node
].list_mutex
);
1166 list_for_each_entry(spu
, &cbe_spu_info
[node
].spus
, cbe_list
)
1167 if (spu
->alloc_state
!= SPU_FREE
)
1168 spu
->alloc_state
= SPU_FREE
;
1169 mutex_unlock(&cbe_spu_info
[node
].list_mutex
);