[mirror_ubuntu-hirsute-kernel.git] / arch / powerpc / platforms / cell / spufs / sched.c

/* sched.c - SPU scheduler.
 *
 * Copyright (C) IBM 2005
 * Author: Mark Nutter <mnutter@us.ibm.com>
 *
 * SPU scheduler, based on Linux thread priority.  For now use
 * a simple "cooperative" yield model with no preemption.  SPU
 * scheduling will eventually be preemptive: When a thread with
 * a higher static priority gets ready to run, then an active SPU
 * context will be preempted and returned to the waitq.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#undef DEBUG

#include <linux/config.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/completion.h>
#include <linux/vmalloc.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/unistd.h>

#include <asm/io.h>
#include <asm/mmu_context.h>
#include <asm/spu.h>
#include <asm/spu_csa.h>
#include "spufs.h"

#define SPU_BITMAP_SIZE (((MAX_PRIO+BITS_PER_LONG)/BITS_PER_LONG)+1)
struct spu_prio_array {
	atomic_t nr_blocked;
	unsigned long bitmap[SPU_BITMAP_SIZE];
	wait_queue_head_t waitq[MAX_PRIO];
};

/* spu_runqueue - This is the main runqueue data structure for SPUs. */
struct spu_runqueue {
	struct semaphore sem;
	unsigned long nr_active;
	unsigned long nr_idle;
	unsigned long nr_switches;
	struct list_head active_list;
	struct list_head idle_list;
	struct spu_prio_array prio;
};

static struct spu_runqueue *spu_runqueues = NULL;

static inline struct spu_runqueue *spu_rq(void)
{
	/* Future: make this a per-NODE array,
	 * and use cpu_to_node(smp_processor_id())
	 */
	return spu_runqueues;
}

static inline struct spu *del_idle(struct spu_runqueue *rq)
{
	struct spu *spu;

	BUG_ON(rq->nr_idle <= 0);
	BUG_ON(list_empty(&rq->idle_list));
	/* Future: Move SPU out of low-power SRI state. */
	spu = list_entry(rq->idle_list.next, struct spu, sched_list);
	list_del_init(&spu->sched_list);
	rq->nr_idle--;
	return spu;
}

static inline void del_active(struct spu_runqueue *rq, struct spu *spu)
{
	BUG_ON(rq->nr_active <= 0);
	BUG_ON(list_empty(&rq->active_list));
	list_del_init(&spu->sched_list);
	rq->nr_active--;
}

static inline void add_idle(struct spu_runqueue *rq, struct spu *spu)
{
	/* Future: Put SPU into low-power SRI state. */
	list_add_tail(&spu->sched_list, &rq->idle_list);
	rq->nr_idle++;
}

static inline void add_active(struct spu_runqueue *rq, struct spu *spu)
{
	rq->nr_active++;
	rq->nr_switches++;
	list_add_tail(&spu->sched_list, &rq->active_list);
}

static void prio_wakeup(struct spu_runqueue *rq)
{
	if (atomic_read(&rq->prio.nr_blocked) && rq->nr_idle) {
		int best = sched_find_first_bit(rq->prio.bitmap);
		if (best < MAX_PRIO) {
			wait_queue_head_t *wq = &rq->prio.waitq[best];
			wake_up_interruptible_nr(wq, 1);
		}
	}
}

static void prio_wait(struct spu_runqueue *rq, struct spu_context *ctx,
		      u64 flags)
{
	int prio = current->prio;
	wait_queue_head_t *wq = &rq->prio.waitq[prio];
	DEFINE_WAIT(wait);

	__set_bit(prio, rq->prio.bitmap);
	atomic_inc(&rq->prio.nr_blocked);
	prepare_to_wait_exclusive(wq, &wait, TASK_INTERRUPTIBLE);
	if (!signal_pending(current)) {
		up(&rq->sem);
		up_write(&ctx->state_sema);
		pr_debug("%s: pid=%d prio=%d\n", __FUNCTION__,
			 current->pid, current->prio);
		schedule();
		down_write(&ctx->state_sema);
		down(&rq->sem);
	}
	finish_wait(wq, &wait);
	atomic_dec(&rq->prio.nr_blocked);
	if (!waitqueue_active(wq))
		__clear_bit(prio, rq->prio.bitmap);
}

static inline int is_best_prio(struct spu_runqueue *rq)
{
	int best_prio;

	best_prio = sched_find_first_bit(rq->prio.bitmap);
	return (current->prio < best_prio) ? 1 : 0;
}

static inline void mm_needs_global_tlbie(struct mm_struct *mm)
{
	/* Global TLBIE broadcast required with SPEs. */
#if (NR_CPUS > 1)
	__cpus_setall(&mm->cpu_vm_mask, NR_CPUS);
#else
	__cpus_setall(&mm->cpu_vm_mask, NR_CPUS+1); /* is this ok? */
#endif
}

static inline void bind_context(struct spu *spu, struct spu_context *ctx)
{
	pr_debug("%s: pid=%d SPU=%d\n", __FUNCTION__, current->pid,
		 spu->number);
	spu->ctx = ctx;
	spu->flags = 0;
	ctx->spu = spu;
	ctx->ops = &spu_hw_ops;
	spu->pid = current->pid;
	spu->prio = current->prio;
	spu->mm = ctx->owner;
	mm_needs_global_tlbie(spu->mm);
	spu->ibox_callback = spufs_ibox_callback;
	spu->wbox_callback = spufs_wbox_callback;
	spu->stop_callback = spufs_stop_callback;
	mb();
	spu_unmap_mappings(ctx);
	spu_restore(&ctx->csa, spu);
}

static inline void unbind_context(struct spu *spu, struct spu_context *ctx)
{
	pr_debug("%s: unbind pid=%d SPU=%d\n", __FUNCTION__,
		 spu->pid, spu->number);
	spu_unmap_mappings(ctx);
	spu_save(&ctx->csa, spu);
	ctx->state = SPU_STATE_SAVED;
	spu->ibox_callback = NULL;
	spu->wbox_callback = NULL;
	spu->stop_callback = NULL;
	spu->mm = NULL;
	spu->pid = 0;
	spu->prio = MAX_PRIO;
	ctx->ops = &spu_backing_ops;
	ctx->spu = NULL;
	spu->ctx = NULL;
}

static struct spu *preempt_active(struct spu_runqueue *rq)
{
	struct list_head *p;
	struct spu *worst, *spu;

	worst = list_entry(rq->active_list.next, struct spu, sched_list);
	list_for_each(p, &rq->active_list) {
		spu = list_entry(p, struct spu, sched_list);
		if (spu->prio > worst->prio) {
			worst = spu;
		}
	}
	if (current->prio < worst->prio) {
		struct spu_context *ctx = worst->ctx;

		spu = worst;
		if (down_write_trylock(&ctx->state_sema)) {
			pr_debug("%s: booting pid=%d from SPU %d\n",
				 __FUNCTION__, spu->pid, spu->number);
			del_active(rq, spu);
			up(&rq->sem);
			wake_up_all(&ctx->stop_wq);
			ctx->ops->runcntl_stop(ctx);
			unbind_context(spu, ctx);
			up_write(&ctx->state_sema);
			return spu;
		}
	}
	return NULL;
}

static struct spu *get_idle_spu(struct spu_context *ctx, u64 flags)
{
	struct spu_runqueue *rq;
	struct spu *spu = NULL;

	rq = spu_rq();
	down(&rq->sem);
	for (;;) {
		if (rq->nr_idle > 0) {
			if (is_best_prio(rq)) {
				/* Fall through. */
				spu = del_idle(rq);
				break;
			} else {
				prio_wakeup(rq);
				up(&rq->sem);
				yield();
				if (signal_pending(current)) {
					return NULL;
				}
				rq = spu_rq();
				down(&rq->sem);
				continue;
			}
		} else {
			if (is_best_prio(rq)) {
				if ((spu = preempt_active(rq)) != NULL)
					return spu;
			}
			prio_wait(rq, ctx, flags);
			if (signal_pending(current)) {
				prio_wakeup(rq);
				spu = NULL;
				break;
			}
			continue;
		}
	}
	up(&rq->sem);
	return spu;
}

static void put_idle_spu(struct spu *spu)
{
	struct spu_runqueue *rq = spu->rq;

	down(&rq->sem);
	add_idle(rq, spu);
	prio_wakeup(rq);
	up(&rq->sem);
}

static int get_active_spu(struct spu *spu)
{
	struct spu_runqueue *rq = spu->rq;
	struct list_head *p;
	struct spu *tmp;
	int rc = 0;

	down(&rq->sem);
	list_for_each(p, &rq->active_list) {
		tmp = list_entry(p, struct spu, sched_list);
		if (tmp == spu) {
			del_active(rq, spu);
			rc = 1;
			break;
		}
	}
	up(&rq->sem);
	return rc;
}

static void put_active_spu(struct spu *spu)
{
	struct spu_runqueue *rq = spu->rq;

	down(&rq->sem);
	add_active(rq, spu);
	up(&rq->sem);
}

/* Lock order:
 *	spu_activate() & spu_deactivate() require the
 *	caller to have down_write(&ctx->state_sema).
 *
 *	The rq->sem is breifly held (inside or outside a
 *	given ctx lock) for list management, but is never
 *	held during save/restore.
 */

int spu_activate(struct spu_context *ctx, u64 flags)
{
	struct spu *spu;

	if (ctx->spu)
		return 0;
	spu = get_idle_spu(ctx, flags);
	if (!spu)
		return (signal_pending(current)) ? -ERESTARTSYS : -EAGAIN;
	bind_context(spu, ctx);
	put_active_spu(spu);
	return 0;
}

void spu_deactivate(struct spu_context *ctx)
{
	struct spu *spu;
	int needs_idle;

	spu = ctx->spu;
	if (!spu)
		return;
	needs_idle = get_active_spu(spu);
	unbind_context(spu, ctx);
	if (needs_idle)
		put_idle_spu(spu);
}

void spu_yield(struct spu_context *ctx)
{
	struct spu *spu;
	int need_yield = 0;

	down_write(&ctx->state_sema);
	spu = ctx->spu;
	if (spu && (sched_find_first_bit(spu->rq->prio.bitmap) < MAX_PRIO)) {
		pr_debug("%s: yielding SPU %d\n", __FUNCTION__, spu->number);
		spu_deactivate(ctx);
		ctx->state = SPU_STATE_SAVED;
		need_yield = 1;
	}
	up_write(&ctx->state_sema);
	if (unlikely(need_yield))
		yield();
}

int __init spu_sched_init(void)
{
	struct spu_runqueue *rq;
	struct spu *spu;
	int i;

	rq = spu_runqueues = kmalloc(sizeof(struct spu_runqueue), GFP_KERNEL);
	if (!rq) {
		printk(KERN_WARNING "%s: Unable to allocate runqueues.\n",
		       __FUNCTION__);
		return 1;
	}
	memset(rq, 0, sizeof(struct spu_runqueue));
	init_MUTEX(&rq->sem);
	INIT_LIST_HEAD(&rq->active_list);
	INIT_LIST_HEAD(&rq->idle_list);
	rq->nr_active = 0;
	rq->nr_idle = 0;
	rq->nr_switches = 0;
	atomic_set(&rq->prio.nr_blocked, 0);
	for (i = 0; i < MAX_PRIO; i++) {
		init_waitqueue_head(&rq->prio.waitq[i]);
		__clear_bit(i, rq->prio.bitmap);
	}
	__set_bit(MAX_PRIO, rq->prio.bitmap);
	for (;;) {
		spu = spu_alloc();
		if (!spu)
			break;
		pr_debug("%s: adding SPU[%d]\n", __FUNCTION__, spu->number);
		add_idle(rq, spu);
		spu->rq = rq;
	}
	if (!rq->nr_idle) {
		printk(KERN_WARNING "%s: No available SPUs.\n", __FUNCTION__);
		kfree(rq);
		return 1;
	}
	return 0;
}

void __exit spu_sched_exit(void)
{
	struct spu_runqueue *rq = spu_rq();
	struct spu *spu;

	if (!rq) {
		printk(KERN_WARNING "%s: no runqueues!\n", __FUNCTION__);
		return;
	}
	while (rq->nr_idle > 0) {
		spu = del_idle(rq);
		if (!spu)
			break;
		spu_free(spu);
	}
	kfree(rq);
}
Commit	Line	Data
8b3d6663 AB	1	/* sched.c - SPU scheduler.
	2	*
	3	* Copyright (C) IBM 2005
	4	* Author: Mark Nutter <mnutter@us.ibm.com>
	5	*
	6	* SPU scheduler, based on Linux thread priority. For now use
	7	* a simple "cooperative" yield model with no preemption. SPU
	8	* scheduling will eventually be preemptive: When a thread with
	9	* a higher static priority gets ready to run, then an active SPU
	10	* context will be preempted and returned to the waitq.
	11	*
	12	* This program is free software; you can redistribute it and/or modify
	13	* it under the terms of the GNU General Public License as published by
	14	* the Free Software Foundation; either version 2, or (at your option)
	15	* any later version.
	16	*
	17	* This program is distributed in the hope that it will be useful,
	18	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	20	* GNU General Public License for more details.
	21	*
	22	* You should have received a copy of the GNU General Public License
	23	* along with this program; if not, write to the Free Software
	24	* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
	25	*/
	26
3b3d22cb AB	27	#undef DEBUG
3b3d22cb AB	28
8b3d6663 AB	29	#include <linux/config.h>
	30	#include <linux/module.h>
	31	#include <linux/errno.h>
	32	#include <linux/sched.h>
	33	#include <linux/kernel.h>
	34	#include <linux/mm.h>
	35	#include <linux/completion.h>
	36	#include <linux/vmalloc.h>
	37	#include <linux/smp.h>
	38	#include <linux/smp_lock.h>
	39	#include <linux/stddef.h>
	40	#include <linux/unistd.h>
	41
	42	#include <asm/io.h>
	43	#include <asm/mmu_context.h>
	44	#include <asm/spu.h>
	45	#include <asm/spu_csa.h>
	46	#include "spufs.h"
	47
	48	#define SPU_BITMAP_SIZE (((MAX_PRIO+BITS_PER_LONG)/BITS_PER_LONG)+1)
	49	struct spu_prio_array {
	50	atomic_t nr_blocked;
	51	unsigned long bitmap[SPU_BITMAP_SIZE];
	52	wait_queue_head_t waitq[MAX_PRIO];
	53	};
	54
	55	/* spu_runqueue - This is the main runqueue data structure for SPUs. */
	56	struct spu_runqueue {
	57	struct semaphore sem;
	58	unsigned long nr_active;
	59	unsigned long nr_idle;
	60	unsigned long nr_switches;
	61	struct list_head active_list;
	62	struct list_head idle_list;
	63	struct spu_prio_array prio;
	64	};
	65
	66	static struct spu_runqueue *spu_runqueues = NULL;
	67
	68	static inline struct spu_runqueue *spu_rq(void)
	69	{
	70	/* Future: make this a per-NODE array,
	71	* and use cpu_to_node(smp_processor_id())
	72	*/
	73	return spu_runqueues;
	74	}
	75
	76	static inline struct spu del_idle(struct spu_runqueue rq)
	77	{
	78	struct spu *spu;
	79
	80	BUG_ON(rq->nr_idle <= 0);
	81	BUG_ON(list_empty(&rq->idle_list));
	82	/* Future: Move SPU out of low-power SRI state. */
	83	spu = list_entry(rq->idle_list.next, struct spu, sched_list);
	84	list_del_init(&spu->sched_list);
	85	rq->nr_idle--;
	86	return spu;
	87	}
	88
	89	static inline void del_active(struct spu_runqueue rq, struct spu spu)
	90	{
	91	BUG_ON(rq->nr_active <= 0);
	92	BUG_ON(list_empty(&rq->active_list));
93	list_del_init(&spu->sched_list);
94	rq->nr_active--;
95	}
96
97	static inline void add_idle(struct spu_runqueue rq, struct spu spu)
98	{
99	/* Future: Put SPU into low-power SRI state. */
100	list_add_tail(&spu->sched_list, &rq->idle_list);
101	rq->nr_idle++;
102	}
103
104	static inline void add_active(struct spu_runqueue rq, struct spu spu)
105	{
106	rq->nr_active++;
107	rq->nr_switches++;
108	list_add_tail(&spu->sched_list, &rq->active_list);
109	}
110
111	static void prio_wakeup(struct spu_runqueue *rq)
112	{
113	if (atomic_read(&rq->prio.nr_blocked) && rq->nr_idle) {
114	int best = sched_find_first_bit(rq->prio.bitmap);
115	if (best < MAX_PRIO) {
116	wait_queue_head_t *wq = &rq->prio.waitq[best];
117	wake_up_interruptible_nr(wq, 1);
118	}
119	}
120	}
121
5110459f AB	122	static void prio_wait(struct spu_runqueue rq, struct spu_context ctx,
5110459f AB	123	u64 flags)
8b3d6663 AB	124	{
	125	int prio = current->prio;
	126	wait_queue_head_t *wq = &rq->prio.waitq[prio];
	127	DEFINE_WAIT(wait);
	128
	129	__set_bit(prio, rq->prio.bitmap);
	130	atomic_inc(&rq->prio.nr_blocked);
	131	prepare_to_wait_exclusive(wq, &wait, TASK_INTERRUPTIBLE);
	132	if (!signal_pending(current)) {
	133	up(&rq->sem);
5110459f	134	up_write(&ctx->state_sema);
8b3d6663 AB	135	pr_debug("%s: pid=%d prio=%d\n", __FUNCTION__,
	136	current->pid, current->prio);
	137	schedule();
5110459f	138	down_write(&ctx->state_sema);
8b3d6663 AB	139	down(&rq->sem);
	140	}
	141	finish_wait(wq, &wait);
	142	atomic_dec(&rq->prio.nr_blocked);
	143	if (!waitqueue_active(wq))
	144	__clear_bit(prio, rq->prio.bitmap);
	145	}
	146
	147	static inline int is_best_prio(struct spu_runqueue *rq)
	148	{
	149	int best_prio;
	150
	151	best_prio = sched_find_first_bit(rq->prio.bitmap);
	152	return (current->prio < best_prio) ? 1 : 0;
	153	}
	154
	155	static inline void mm_needs_global_tlbie(struct mm_struct *mm)
	156	{
	157	/* Global TLBIE broadcast required with SPEs. */
	158	#if (NR_CPUS > 1)
	159	__cpus_setall(&mm->cpu_vm_mask, NR_CPUS);
	160	#else
	161	__cpus_setall(&mm->cpu_vm_mask, NR_CPUS+1); /* is this ok? */
	162	#endif
	163	}
	164
	165	static inline void bind_context(struct spu spu, struct spu_context ctx)
	166	{
	167	pr_debug("%s: pid=%d SPU=%d\n", __FUNCTION__, current->pid,
	168	spu->number);
	169	spu->ctx = ctx;
	170	spu->flags = 0;
	171	ctx->spu = spu;
	172	ctx->ops = &spu_hw_ops;
	173	spu->pid = current->pid;
	174	spu->prio = current->prio;
	175	spu->mm = ctx->owner;
	176	mm_needs_global_tlbie(spu->mm);
	177	spu->ibox_callback = spufs_ibox_callback;
	178	spu->wbox_callback = spufs_wbox_callback;
5110459f	179	spu->stop_callback = spufs_stop_callback;
8b3d6663	180	mb();
5110459f	181	spu_unmap_mappings(ctx);
8b3d6663 AB	182	spu_restore(&ctx->csa, spu);
	183	}
	184
	185	static inline void unbind_context(struct spu spu, struct spu_context ctx)
	186	{
	187	pr_debug("%s: unbind pid=%d SPU=%d\n", __FUNCTION__,
	188	spu->pid, spu->number);
5110459f	189	spu_unmap_mappings(ctx);
8b3d6663 AB	190	spu_save(&ctx->csa, spu);
	191	ctx->state = SPU_STATE_SAVED;
	192	spu->ibox_callback = NULL;
	193	spu->wbox_callback = NULL;
5110459f	194	spu->stop_callback = NULL;
8b3d6663 AB	195	spu->mm = NULL;
	196	spu->pid = 0;
	197	spu->prio = MAX_PRIO;
	198	ctx->ops = &spu_backing_ops;
	199	ctx->spu = NULL;
	200	spu->ctx = NULL;
	201	}
	202
	203	static struct spu preempt_active(struct spu_runqueue rq)
	204	{
	205	struct list_head *p;
5110459f	206	struct spu worst, spu;
8b3d6663	207
5110459f	208	worst = list_entry(rq->active_list.next, struct spu, sched_list);
8b3d6663 AB	209	list_for_each(p, &rq->active_list) {
8b3d6663 AB	210	spu = list_entry(p, struct spu, sched_list);
5110459f AB	211	if (spu->prio > worst->prio) {
	212	worst = spu;
	213	}
	214	}
	215	if (current->prio < worst->prio) {
	216	struct spu_context *ctx = worst->ctx;
	217
	218	spu = worst;
	219	if (down_write_trylock(&ctx->state_sema)) {
	220	pr_debug("%s: booting pid=%d from SPU %d\n",
	221	__FUNCTION__, spu->pid, spu->number);
	222	del_active(rq, spu);
	223	up(&rq->sem);
	224	wake_up_all(&ctx->stop_wq);
	225	ctx->ops->runcntl_stop(ctx);
	226	unbind_context(spu, ctx);
	227	up_write(&ctx->state_sema);
	228	return spu;
8b3d6663 AB	229	}
	230	}
	231	return NULL;
	232	}
	233
5110459f	234	static struct spu get_idle_spu(struct spu_context ctx, u64 flags)
8b3d6663 AB	235	{
	236	struct spu_runqueue *rq;
	237	struct spu *spu = NULL;
	238
	239	rq = spu_rq();
	240	down(&rq->sem);
	241	for (;;) {
	242	if (rq->nr_idle > 0) {
	243	if (is_best_prio(rq)) {
	244	/* Fall through. */
	245	spu = del_idle(rq);
	246	break;
	247	} else {
	248	prio_wakeup(rq);
	249	up(&rq->sem);
	250	yield();
	251	if (signal_pending(current)) {
	252	return NULL;
	253	}
	254	rq = spu_rq();
	255	down(&rq->sem);
	256	continue;
	257	}
	258	} else {
	259	if (is_best_prio(rq)) {
	260	if ((spu = preempt_active(rq)) != NULL)
	261	return spu;
	262	}
5110459f	263	prio_wait(rq, ctx, flags);
8b3d6663 AB	264	if (signal_pending(current)) {
	265	prio_wakeup(rq);
	266	spu = NULL;
	267	break;
	268	}
	269	continue;
	270	}
	271	}
	272	up(&rq->sem);
	273	return spu;
	274	}
	275
	276	static void put_idle_spu(struct spu *spu)
	277	{
	278	struct spu_runqueue *rq = spu->rq;
	279
	280	down(&rq->sem);
	281	add_idle(rq, spu);
	282	prio_wakeup(rq);
	283	up(&rq->sem);
	284	}
	285
	286	static int get_active_spu(struct spu *spu)
	287	{
	288	struct spu_runqueue *rq = spu->rq;
	289	struct list_head *p;
	290	struct spu *tmp;
	291	int rc = 0;
	292
	293	down(&rq->sem);
	294	list_for_each(p, &rq->active_list) {
	295	tmp = list_entry(p, struct spu, sched_list);
	296	if (tmp == spu) {
	297	del_active(rq, spu);
	298	rc = 1;
	299	break;
	300	}
	301	}
	302	up(&rq->sem);
	303	return rc;
	304	}
	305
	306	static void put_active_spu(struct spu *spu)
	307	{
	308	struct spu_runqueue *rq = spu->rq;
	309
	310	down(&rq->sem);
	311	add_active(rq, spu);
	312	up(&rq->sem);
	313	}
	314
	315	/* Lock order:
	316	* spu_activate() & spu_deactivate() require the
	317	* caller to have down_write(&ctx->state_sema).
	318	*
	319	* The rq->sem is breifly held (inside or outside a
	320	* given ctx lock) for list management, but is never
	321	* held during save/restore.
	322	*/
	323
	324	int spu_activate(struct spu_context *ctx, u64 flags)
	325	{
	326	struct spu *spu;
	327
328	if (ctx->spu)
329	return 0;
5110459f	330	spu = get_idle_spu(ctx, flags);
8b3d6663 AB	331	if (!spu)
	332	return (signal_pending(current)) ? -ERESTARTSYS : -EAGAIN;
	333	bind_context(spu, ctx);
	334	put_active_spu(spu);
	335	return 0;
	336	}
	337
	338	void spu_deactivate(struct spu_context *ctx)
	339	{
	340	struct spu *spu;
	341	int needs_idle;
	342
	343	spu = ctx->spu;
	344	if (!spu)
	345	return;
	346	needs_idle = get_active_spu(spu);
	347	unbind_context(spu, ctx);
	348	if (needs_idle)
	349	put_idle_spu(spu);
	350	}
	351
	352	void spu_yield(struct spu_context *ctx)
	353	{
	354	struct spu *spu;
5110459f	355	int need_yield = 0;
8b3d6663	356
5110459f	357	down_write(&ctx->state_sema);
8b3d6663	358	spu = ctx->spu;
5110459f	359	if (spu && (sched_find_first_bit(spu->rq->prio.bitmap) < MAX_PRIO)) {
8b3d6663 AB	360	pr_debug("%s: yielding SPU %d\n", __FUNCTION__, spu->number);
	361	spu_deactivate(ctx);
	362	ctx->state = SPU_STATE_SAVED;
5110459f	363	need_yield = 1;
8b3d6663 AB	364	}
8b3d6663 AB	365	up_write(&ctx->state_sema);
5110459f AB	366	if (unlikely(need_yield))
5110459f AB	367	yield();
8b3d6663 AB	368	}
	369
	370	int __init spu_sched_init(void)
	371	{
	372	struct spu_runqueue *rq;
	373	struct spu *spu;
	374	int i;
	375
	376	rq = spu_runqueues = kmalloc(sizeof(struct spu_runqueue), GFP_KERNEL);
	377	if (!rq) {
	378	printk(KERN_WARNING "%s: Unable to allocate runqueues.\n",
	379	__FUNCTION__);
	380	return 1;
	381	}
	382	memset(rq, 0, sizeof(struct spu_runqueue));
	383	init_MUTEX(&rq->sem);
	384	INIT_LIST_HEAD(&rq->active_list);
	385	INIT_LIST_HEAD(&rq->idle_list);
	386	rq->nr_active = 0;
	387	rq->nr_idle = 0;
	388	rq->nr_switches = 0;
	389	atomic_set(&rq->prio.nr_blocked, 0);
	390	for (i = 0; i < MAX_PRIO; i++) {
	391	init_waitqueue_head(&rq->prio.waitq[i]);
	392	__clear_bit(i, rq->prio.bitmap);
	393	}
	394	__set_bit(MAX_PRIO, rq->prio.bitmap);
	395	for (;;) {
	396	spu = spu_alloc();
	397	if (!spu)
	398	break;
	399	pr_debug("%s: adding SPU[%d]\n", __FUNCTION__, spu->number);
	400	add_idle(rq, spu);
	401	spu->rq = rq;
	402	}
	403	if (!rq->nr_idle) {
	404	printk(KERN_WARNING "%s: No available SPUs.\n", __FUNCTION__);
	405	kfree(rq);
	406	return 1;
	407	}
	408	return 0;
	409	}
	410
	411	void __exit spu_sched_exit(void)
	412	{
	413	struct spu_runqueue *rq = spu_rq();
	414	struct spu *spu;
	415
	416	if (!rq) {
	417	printk(KERN_WARNING "%s: no runqueues!\n", __FUNCTION__);
	418	return;
	419	}
	420	while (rq->nr_idle > 0) {
	421	spu = del_idle(rq);
	422	if (!spu)
	423	break;
	424	spu_free(spu);
	425	}
	426	kfree(rq);
	427	}