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/module.h>
26 #include <linux/errno.h>
27 #include <linux/sched.h>
28 #include <linux/kernel.h>
30 #include <linux/completion.h>
31 #include <linux/vmalloc.h>
32 #include <linux/smp.h>
33 #include <linux/stddef.h>
34 #include <linux/unistd.h>
35 #include <linux/numa.h>
36 #include <linux/mutex.h>
37 #include <linux/notifier.h>
38 #include <linux/kthread.h>
39 #include <linux/pid_namespace.h>
40 #include <linux/proc_fs.h>
41 #include <linux/seq_file.h>
44 #include <asm/mmu_context.h>
46 #include <asm/spu_csa.h>
47 #include <asm/spu_priv1.h>
50 struct spu_prio_array
{
51 DECLARE_BITMAP(bitmap
, MAX_PRIO
);
52 struct list_head runq
[MAX_PRIO
];
54 struct list_head active_list
[MAX_NUMNODES
];
55 struct mutex active_mutex
[MAX_NUMNODES
];
56 int nr_active
[MAX_NUMNODES
];
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
;
66 * Priority of a normal, non-rt, non-niced'd process (aka nice level 0).
68 #define NORMAL_PRIO 120
71 * Frequency of the spu scheduler tick. By default we do one SPU scheduler
72 * tick for every 10 CPU scheduler ticks.
74 #define SPUSCHED_TICK (10)
77 * These are the 'tuning knobs' of the scheduler:
79 * Minimum timeslice is 5 msecs (or 1 spu scheduler tick, whichever is
80 * larger), default timeslice is 100 msecs, maximum timeslice is 800 msecs.
82 #define MIN_SPU_TIMESLICE max(5 * HZ / (1000 * SPUSCHED_TICK), 1)
83 #define DEF_SPU_TIMESLICE (100 * HZ / (1000 * SPUSCHED_TICK))
85 #define MAX_USER_PRIO (MAX_PRIO - MAX_RT_PRIO)
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 * 32-Bit assignment are atomic on powerpc, and we don't care about
112 * memory ordering here because retriving the controlling thread is
113 * per defintion racy.
115 ctx
->tid
= current
->pid
;
118 * We do our own priority calculations, so we normally want
119 * ->static_prio to start with. Unfortunately thies field
120 * contains junk for threads with a realtime scheduling
121 * policy so we have to look at ->prio in this case.
123 if (rt_prio(current
->prio
))
124 ctx
->prio
= current
->prio
;
126 ctx
->prio
= current
->static_prio
;
127 ctx
->policy
= current
->policy
;
130 * A lot of places that don't hold active_mutex poke into
131 * cpus_allowed, including grab_runnable_context which
132 * already holds the runq_lock. So abuse runq_lock
133 * to protect this field aswell.
135 spin_lock(&spu_prio
->runq_lock
);
136 ctx
->cpus_allowed
= current
->cpus_allowed
;
137 spin_unlock(&spu_prio
->runq_lock
);
140 void spu_update_sched_info(struct spu_context
*ctx
)
142 int node
= ctx
->spu
->node
;
144 mutex_lock(&spu_prio
->active_mutex
[node
]);
145 __spu_update_sched_info(ctx
);
146 mutex_unlock(&spu_prio
->active_mutex
[node
]);
149 static int __node_allowed(struct spu_context
*ctx
, int node
)
151 if (nr_cpus_node(node
)) {
152 cpumask_t mask
= node_to_cpumask(node
);
154 if (cpus_intersects(mask
, ctx
->cpus_allowed
))
161 static int node_allowed(struct spu_context
*ctx
, int node
)
165 spin_lock(&spu_prio
->runq_lock
);
166 rval
= __node_allowed(ctx
, node
);
167 spin_unlock(&spu_prio
->runq_lock
);
173 * spu_add_to_active_list - add spu to active list
174 * @spu: spu to add to the active list
176 static void spu_add_to_active_list(struct spu
*spu
)
178 int node
= spu
->node
;
180 mutex_lock(&spu_prio
->active_mutex
[node
]);
181 spu_prio
->nr_active
[node
]++;
182 list_add_tail(&spu
->list
, &spu_prio
->active_list
[node
]);
183 mutex_unlock(&spu_prio
->active_mutex
[node
]);
186 static void __spu_remove_from_active_list(struct spu
*spu
)
188 list_del_init(&spu
->list
);
189 spu_prio
->nr_active
[spu
->node
]--;
193 * spu_remove_from_active_list - remove spu from active list
194 * @spu: spu to remove from the active list
196 static void spu_remove_from_active_list(struct spu
*spu
)
198 int node
= spu
->node
;
200 mutex_lock(&spu_prio
->active_mutex
[node
]);
201 __spu_remove_from_active_list(spu
);
202 mutex_unlock(&spu_prio
->active_mutex
[node
]);
205 static BLOCKING_NOTIFIER_HEAD(spu_switch_notifier
);
207 static void spu_switch_notify(struct spu
*spu
, struct spu_context
*ctx
)
209 blocking_notifier_call_chain(&spu_switch_notifier
,
210 ctx
? ctx
->object_id
: 0, spu
);
213 int spu_switch_event_register(struct notifier_block
* n
)
215 return blocking_notifier_chain_register(&spu_switch_notifier
, n
);
218 int spu_switch_event_unregister(struct notifier_block
* n
)
220 return blocking_notifier_chain_unregister(&spu_switch_notifier
, n
);
224 * spu_bind_context - bind spu context to physical spu
225 * @spu: physical spu to bind to
226 * @ctx: context to bind
228 static void spu_bind_context(struct spu
*spu
, struct spu_context
*ctx
)
230 pr_debug("%s: pid=%d SPU=%d NODE=%d\n", __FUNCTION__
, current
->pid
,
231 spu
->number
, spu
->node
);
232 spuctx_switch_state(ctx
, SPU_UTIL_SYSTEM
);
234 if (ctx
->flags
& SPU_CREATE_NOSCHED
)
235 atomic_inc(&cbe_spu_info
[spu
->node
].reserved_spus
);
237 ctx
->stats
.slb_flt_base
= spu
->stats
.slb_flt
;
238 ctx
->stats
.class2_intr_base
= spu
->stats
.class2_intr
;
243 ctx
->ops
= &spu_hw_ops
;
244 spu
->pid
= current
->pid
;
245 spu_associate_mm(spu
, ctx
->owner
);
246 spu
->ibox_callback
= spufs_ibox_callback
;
247 spu
->wbox_callback
= spufs_wbox_callback
;
248 spu
->stop_callback
= spufs_stop_callback
;
249 spu
->mfc_callback
= spufs_mfc_callback
;
250 spu
->dma_callback
= spufs_dma_callback
;
252 spu_unmap_mappings(ctx
);
253 spu_restore(&ctx
->csa
, spu
);
254 spu
->timestamp
= jiffies
;
255 spu_cpu_affinity_set(spu
, raw_smp_processor_id());
256 spu_switch_notify(spu
, ctx
);
257 ctx
->state
= SPU_STATE_RUNNABLE
;
259 spuctx_switch_state(ctx
, SPU_UTIL_IDLE_LOADED
);
263 * spu_unbind_context - unbind spu context from physical spu
264 * @spu: physical spu to unbind from
265 * @ctx: context to unbind
267 static void spu_unbind_context(struct spu
*spu
, struct spu_context
*ctx
)
269 pr_debug("%s: unbind pid=%d SPU=%d NODE=%d\n", __FUNCTION__
,
270 spu
->pid
, spu
->number
, spu
->node
);
271 spuctx_switch_state(ctx
, SPU_UTIL_SYSTEM
);
273 if (spu
->ctx
->flags
& SPU_CREATE_NOSCHED
)
274 atomic_dec(&cbe_spu_info
[spu
->node
].reserved_spus
);
275 spu_switch_notify(spu
, NULL
);
276 spu_unmap_mappings(ctx
);
277 spu_save(&ctx
->csa
, spu
);
278 spu
->timestamp
= jiffies
;
279 ctx
->state
= SPU_STATE_SAVED
;
280 spu
->ibox_callback
= NULL
;
281 spu
->wbox_callback
= NULL
;
282 spu
->stop_callback
= NULL
;
283 spu
->mfc_callback
= NULL
;
284 spu
->dma_callback
= NULL
;
285 spu_associate_mm(spu
, NULL
);
287 ctx
->ops
= &spu_backing_ops
;
291 ctx
->stats
.slb_flt
+=
292 (spu
->stats
.slb_flt
- ctx
->stats
.slb_flt_base
);
293 ctx
->stats
.class2_intr
+=
294 (spu
->stats
.class2_intr
- ctx
->stats
.class2_intr_base
);
296 /* This maps the underlying spu state to idle */
297 spuctx_switch_state(ctx
, SPU_UTIL_IDLE_LOADED
);
302 * spu_add_to_rq - add a context to the runqueue
303 * @ctx: context to add
305 static void __spu_add_to_rq(struct spu_context
*ctx
)
308 * Unfortunately this code path can be called from multiple threads
309 * on behalf of a single context due to the way the problem state
310 * mmap support works.
312 * Fortunately we need to wake up all these threads at the same time
313 * and can simply skip the runqueue addition for every but the first
314 * thread getting into this codepath.
316 * It's still quite hacky, and long-term we should proxy all other
317 * threads through the owner thread so that spu_run is in control
318 * of all the scheduling activity for a given context.
320 if (list_empty(&ctx
->rq
)) {
321 list_add_tail(&ctx
->rq
, &spu_prio
->runq
[ctx
->prio
]);
322 set_bit(ctx
->prio
, spu_prio
->bitmap
);
323 if (!spu_prio
->nr_waiting
++)
324 __mod_timer(&spusched_timer
, jiffies
+ SPUSCHED_TICK
);
328 static void __spu_del_from_rq(struct spu_context
*ctx
)
330 int prio
= ctx
->prio
;
332 if (!list_empty(&ctx
->rq
)) {
333 if (!--spu_prio
->nr_waiting
)
334 del_timer(&spusched_timer
);
335 list_del_init(&ctx
->rq
);
337 if (list_empty(&spu_prio
->runq
[prio
]))
338 clear_bit(prio
, spu_prio
->bitmap
);
342 static void spu_prio_wait(struct spu_context
*ctx
)
346 spin_lock(&spu_prio
->runq_lock
);
347 prepare_to_wait_exclusive(&ctx
->stop_wq
, &wait
, TASK_INTERRUPTIBLE
);
348 if (!signal_pending(current
)) {
349 __spu_add_to_rq(ctx
);
350 spin_unlock(&spu_prio
->runq_lock
);
351 mutex_unlock(&ctx
->state_mutex
);
353 mutex_lock(&ctx
->state_mutex
);
354 spin_lock(&spu_prio
->runq_lock
);
355 __spu_del_from_rq(ctx
);
357 spin_unlock(&spu_prio
->runq_lock
);
358 __set_current_state(TASK_RUNNING
);
359 remove_wait_queue(&ctx
->stop_wq
, &wait
);
362 static struct spu
*spu_get_idle(struct spu_context
*ctx
)
364 struct spu
*spu
= NULL
;
365 int node
= cpu_to_node(raw_smp_processor_id());
368 for (n
= 0; n
< MAX_NUMNODES
; n
++, node
++) {
369 node
= (node
< MAX_NUMNODES
) ? node
: 0;
370 if (!node_allowed(ctx
, node
))
372 spu
= spu_alloc_node(node
);
380 * find_victim - find a lower priority context to preempt
381 * @ctx: canidate context for running
383 * Returns the freed physical spu to run the new context on.
385 static struct spu
*find_victim(struct spu_context
*ctx
)
387 struct spu_context
*victim
= NULL
;
392 * Look for a possible preemption candidate on the local node first.
393 * If there is no candidate look at the other nodes. This isn't
394 * exactly fair, but so far the whole spu schedule tries to keep
395 * a strong node affinity. We might want to fine-tune this in
399 node
= cpu_to_node(raw_smp_processor_id());
400 for (n
= 0; n
< MAX_NUMNODES
; n
++, node
++) {
401 node
= (node
< MAX_NUMNODES
) ? node
: 0;
402 if (!node_allowed(ctx
, node
))
405 mutex_lock(&spu_prio
->active_mutex
[node
]);
406 list_for_each_entry(spu
, &spu_prio
->active_list
[node
], list
) {
407 struct spu_context
*tmp
= spu
->ctx
;
409 if (tmp
->prio
> ctx
->prio
&&
410 (!victim
|| tmp
->prio
> victim
->prio
))
413 mutex_unlock(&spu_prio
->active_mutex
[node
]);
417 * This nests ctx->state_mutex, but we always lock
418 * higher priority contexts before lower priority
419 * ones, so this is safe until we introduce
420 * priority inheritance schemes.
422 if (!mutex_trylock(&victim
->state_mutex
)) {
430 * This race can happen because we've dropped
431 * the active list mutex. No a problem, just
432 * restart the search.
434 mutex_unlock(&victim
->state_mutex
);
438 spu_remove_from_active_list(spu
);
439 spu_unbind_context(spu
, victim
);
440 victim
->stats
.invol_ctx_switch
++;
441 spu
->stats
.invol_ctx_switch
++;
442 mutex_unlock(&victim
->state_mutex
);
444 * We need to break out of the wait loop in spu_run
445 * manually to ensure this context gets put on the
446 * runqueue again ASAP.
448 wake_up(&victim
->stop_wq
);
457 * spu_activate - find a free spu for a context and execute it
458 * @ctx: spu context to schedule
459 * @flags: flags (currently ignored)
461 * Tries to find a free spu to run @ctx. If no free spu is available
462 * add the context to the runqueue so it gets woken up once an spu
465 int spu_activate(struct spu_context
*ctx
, unsigned long flags
)
471 * If there are multiple threads waiting for a single context
472 * only one actually binds the context while the others will
473 * only be able to acquire the state_mutex once the context
474 * already is in runnable state.
479 spu
= spu_get_idle(ctx
);
481 * If this is a realtime thread we try to get it running by
482 * preempting a lower priority thread.
484 if (!spu
&& rt_prio(ctx
->prio
))
485 spu
= find_victim(ctx
);
487 spu_bind_context(spu
, ctx
);
488 spu_add_to_active_list(spu
);
493 } while (!signal_pending(current
));
499 * grab_runnable_context - try to find a runnable context
501 * Remove the highest priority context on the runqueue and return it
502 * to the caller. Returns %NULL if no runnable context was found.
504 static struct spu_context
*grab_runnable_context(int prio
, int node
)
506 struct spu_context
*ctx
;
509 spin_lock(&spu_prio
->runq_lock
);
510 best
= find_first_bit(spu_prio
->bitmap
, prio
);
511 while (best
< prio
) {
512 struct list_head
*rq
= &spu_prio
->runq
[best
];
514 list_for_each_entry(ctx
, rq
, rq
) {
515 /* XXX(hch): check for affinity here aswell */
516 if (__node_allowed(ctx
, node
)) {
517 __spu_del_from_rq(ctx
);
525 spin_unlock(&spu_prio
->runq_lock
);
529 static int __spu_deactivate(struct spu_context
*ctx
, int force
, int max_prio
)
531 struct spu
*spu
= ctx
->spu
;
532 struct spu_context
*new = NULL
;
535 new = grab_runnable_context(max_prio
, spu
->node
);
537 spu_remove_from_active_list(spu
);
538 spu_unbind_context(spu
, ctx
);
539 ctx
->stats
.vol_ctx_switch
++;
540 spu
->stats
.vol_ctx_switch
++;
543 wake_up(&new->stop_wq
);
552 * spu_deactivate - unbind a context from it's physical spu
553 * @ctx: spu context to unbind
555 * Unbind @ctx from the physical spu it is running on and schedule
556 * the highest priority context to run on the freed physical spu.
558 void spu_deactivate(struct spu_context
*ctx
)
560 __spu_deactivate(ctx
, 1, MAX_PRIO
);
564 * spu_yield - yield a physical spu if others are waiting
565 * @ctx: spu context to yield
567 * Check if there is a higher priority context waiting and if yes
568 * unbind @ctx from the physical spu and schedule the highest
569 * priority context to run on the freed physical spu instead.
571 void spu_yield(struct spu_context
*ctx
)
573 if (!(ctx
->flags
& SPU_CREATE_NOSCHED
)) {
574 mutex_lock(&ctx
->state_mutex
);
575 __spu_deactivate(ctx
, 0, MAX_PRIO
);
576 mutex_unlock(&ctx
->state_mutex
);
580 static void spusched_tick(struct spu_context
*ctx
)
582 if (ctx
->flags
& SPU_CREATE_NOSCHED
)
584 if (ctx
->policy
== SCHED_FIFO
)
587 if (--ctx
->time_slice
)
591 * Unfortunately active_mutex ranks outside of state_mutex, so
592 * we have to trylock here. If we fail give the context another
593 * tick and try again.
595 if (mutex_trylock(&ctx
->state_mutex
)) {
596 struct spu
*spu
= ctx
->spu
;
597 struct spu_context
*new;
599 new = grab_runnable_context(ctx
->prio
+ 1, spu
->node
);
602 __spu_remove_from_active_list(spu
);
603 spu_unbind_context(spu
, ctx
);
604 ctx
->stats
.invol_ctx_switch
++;
605 spu
->stats
.invol_ctx_switch
++;
607 wake_up(&new->stop_wq
);
609 * We need to break out of the wait loop in
610 * spu_run manually to ensure this context
611 * gets put on the runqueue again ASAP.
613 wake_up(&ctx
->stop_wq
);
615 spu_set_timeslice(ctx
);
616 mutex_unlock(&ctx
->state_mutex
);
623 * count_active_contexts - count nr of active tasks
625 * Return the number of tasks currently running or waiting to run.
627 * Note that we don't take runq_lock / active_mutex here. Reading
628 * a single 32bit value is atomic on powerpc, and we don't care
629 * about memory ordering issues here.
631 static unsigned long count_active_contexts(void)
633 int nr_active
= 0, node
;
635 for (node
= 0; node
< MAX_NUMNODES
; node
++)
636 nr_active
+= spu_prio
->nr_active
[node
];
637 nr_active
+= spu_prio
->nr_waiting
;
643 * spu_calc_load - given tick count, update the avenrun load estimates.
646 * No locking against reading these values from userspace, as for
647 * the CPU loadavg code.
649 static void spu_calc_load(unsigned long ticks
)
651 unsigned long active_tasks
; /* fixed-point */
652 static int count
= LOAD_FREQ
;
656 if (unlikely(count
< 0)) {
657 active_tasks
= count_active_contexts() * FIXED_1
;
659 CALC_LOAD(spu_avenrun
[0], EXP_1
, active_tasks
);
660 CALC_LOAD(spu_avenrun
[1], EXP_5
, active_tasks
);
661 CALC_LOAD(spu_avenrun
[2], EXP_15
, active_tasks
);
667 static void spusched_wake(unsigned long data
)
669 mod_timer(&spusched_timer
, jiffies
+ SPUSCHED_TICK
);
670 wake_up_process(spusched_task
);
671 spu_calc_load(SPUSCHED_TICK
);
674 static int spusched_thread(void *unused
)
676 struct spu
*spu
, *next
;
679 while (!kthread_should_stop()) {
680 set_current_state(TASK_INTERRUPTIBLE
);
682 for (node
= 0; node
< MAX_NUMNODES
; node
++) {
683 mutex_lock(&spu_prio
->active_mutex
[node
]);
684 list_for_each_entry_safe(spu
, next
,
685 &spu_prio
->active_list
[node
],
687 spusched_tick(spu
->ctx
);
688 mutex_unlock(&spu_prio
->active_mutex
[node
]);
695 #define LOAD_INT(x) ((x) >> FSHIFT)
696 #define LOAD_FRAC(x) LOAD_INT(((x) & (FIXED_1-1)) * 100)
698 static int show_spu_loadavg(struct seq_file
*s
, void *private)
702 a
= spu_avenrun
[0] + (FIXED_1
/200);
703 b
= spu_avenrun
[1] + (FIXED_1
/200);
704 c
= spu_avenrun
[2] + (FIXED_1
/200);
707 * Note that last_pid doesn't really make much sense for the
708 * SPU loadavg (it even seems very odd on the CPU side..),
709 * but we include it here to have a 100% compatible interface.
711 seq_printf(s
, "%d.%02d %d.%02d %d.%02d %ld/%d %d\n",
712 LOAD_INT(a
), LOAD_FRAC(a
),
713 LOAD_INT(b
), LOAD_FRAC(b
),
714 LOAD_INT(c
), LOAD_FRAC(c
),
715 count_active_contexts(),
716 atomic_read(&nr_spu_contexts
),
717 current
->nsproxy
->pid_ns
->last_pid
);
721 static int spu_loadavg_open(struct inode
*inode
, struct file
*file
)
723 return single_open(file
, show_spu_loadavg
, NULL
);
726 static const struct file_operations spu_loadavg_fops
= {
727 .open
= spu_loadavg_open
,
730 .release
= single_release
,
733 int __init
spu_sched_init(void)
735 struct proc_dir_entry
*entry
;
736 int err
= -ENOMEM
, i
;
738 spu_prio
= kzalloc(sizeof(struct spu_prio_array
), GFP_KERNEL
);
742 for (i
= 0; i
< MAX_PRIO
; i
++) {
743 INIT_LIST_HEAD(&spu_prio
->runq
[i
]);
744 __clear_bit(i
, spu_prio
->bitmap
);
746 for (i
= 0; i
< MAX_NUMNODES
; i
++) {
747 mutex_init(&spu_prio
->active_mutex
[i
]);
748 INIT_LIST_HEAD(&spu_prio
->active_list
[i
]);
750 spin_lock_init(&spu_prio
->runq_lock
);
752 setup_timer(&spusched_timer
, spusched_wake
, 0);
754 spusched_task
= kthread_run(spusched_thread
, NULL
, "spusched");
755 if (IS_ERR(spusched_task
)) {
756 err
= PTR_ERR(spusched_task
);
757 goto out_free_spu_prio
;
760 entry
= create_proc_entry("spu_loadavg", 0, NULL
);
762 goto out_stop_kthread
;
763 entry
->proc_fops
= &spu_loadavg_fops
;
765 pr_debug("spusched: tick: %d, min ticks: %d, default ticks: %d\n",
766 SPUSCHED_TICK
, MIN_SPU_TIMESLICE
, DEF_SPU_TIMESLICE
);
770 kthread_stop(spusched_task
);
777 void spu_sched_exit(void)
779 struct spu
*spu
, *tmp
;
782 remove_proc_entry("spu_loadavg", NULL
);
784 del_timer_sync(&spusched_timer
);
785 kthread_stop(spusched_task
);
787 for (node
= 0; node
< MAX_NUMNODES
; node
++) {
788 mutex_lock(&spu_prio
->active_mutex
[node
]);
789 list_for_each_entry_safe(spu
, tmp
, &spu_prio
->active_list
[node
],
791 list_del_init(&spu
->list
);
794 mutex_unlock(&spu_prio
->active_mutex
[node
]);