arch/powerpc/platforms/cell/spufs/sched.c - maze/linux - Git at Google

 /* sched.c - SPU scheduler.
  *
  * Copyright (C) IBM 2005
  * Author: Mark Nutter <mnutter@us.ibm.com>
  *
  * 2006-03-31	NUMA domains added.
  *
  * 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/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 <linux/numa.h>
 #include <linux/mutex.h>
 #include <linux/notifier.h>

 #include <asm/io.h>
 #include <asm/mmu_context.h>
 #include <asm/spu.h>
 #include <asm/spu_csa.h>
 #include <asm/spu_priv1.h>
 #include "spufs.h"

 #define SPU_MIN_TIMESLICE 	(100 * HZ / 1000)

 #define SPU_BITMAP_SIZE (((MAX_PRIO+BITS_PER_LONG)/BITS_PER_LONG)+1)
 struct spu_prio_array {
 	unsigned long bitmap[SPU_BITMAP_SIZE];
 	wait_queue_head_t waitq[MAX_PRIO];
 	struct list_head active_list[MAX_NUMNODES];
 	struct mutex active_mutex[MAX_NUMNODES];
 };

 static struct spu_prio_array *spu_prio;

 static inline int node_allowed(int node)
 {
 	cpumask_t mask;

 	if (!nr_cpus_node(node))
 		return 0;
 	mask = node_to_cpumask(node);
 	if (!cpus_intersects(mask, current->cpus_allowed))
 		return 0;
 	return 1;
 }

 static inline void mm_needs_global_tlbie(struct mm_struct *mm)
 {
 	int nr = (NR_CPUS > 1) ? NR_CPUS : NR_CPUS + 1;

 	/* Global TLBIE broadcast required with SPEs. */
 	__cpus_setall(&mm->cpu_vm_mask, nr);
 }

 static BLOCKING_NOTIFIER_HEAD(spu_switch_notifier);

 static void spu_switch_notify(struct spu *spu, struct spu_context *ctx)
 {
 	blocking_notifier_call_chain(&spu_switch_notifier,
 			    ctx ? ctx->object_id : 0, spu);
 }

 int spu_switch_event_register(struct notifier_block * n)
 {
 	return blocking_notifier_chain_register(&spu_switch_notifier, n);
 }

 int spu_switch_event_unregister(struct notifier_block * n)
 {
 	return blocking_notifier_chain_unregister(&spu_switch_notifier, n);
 }


 static inline void bind_context(struct spu *spu, struct spu_context *ctx)
 {
 	pr_debug("%s: pid=%d SPU=%d NODE=%d\n", __FUNCTION__, current->pid,
 		 spu->number, spu->node);
 	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;
 	spu->mfc_callback = spufs_mfc_callback;
 	spu->dma_callback = spufs_dma_callback;
 	mb();
 	spu_unmap_mappings(ctx);
 	spu_restore(&ctx->csa, spu);
 	spu->timestamp = jiffies;
 	spu_cpu_affinity_set(spu, raw_smp_processor_id());
 	spu_switch_notify(spu, ctx);
 }

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

 static inline void spu_add_wq(wait_queue_head_t * wq, wait_queue_t * wait,
 			      int prio)
 {
 	prepare_to_wait_exclusive(wq, wait, TASK_INTERRUPTIBLE);
 	set_bit(prio, spu_prio->bitmap);
 }

 static inline void spu_del_wq(wait_queue_head_t * wq, wait_queue_t * wait,
 			      int prio)
 {
 	u64 flags;

 	__set_current_state(TASK_RUNNING);

 	spin_lock_irqsave(&wq->lock, flags);

 	remove_wait_queue_locked(wq, wait);
 	if (list_empty(&wq->task_list))
 		clear_bit(prio, spu_prio->bitmap);

 	spin_unlock_irqrestore(&wq->lock, flags);
 }

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

 	if (ctx->spu)
 		return;

 	spu_add_wq(wq, &wait, prio);

 	if (!signal_pending(current)) {
 		up_write(&ctx->state_sema);
 		pr_debug("%s: pid=%d prio=%d\n", __FUNCTION__,
 			 current->pid, current->prio);
 		schedule();
 		down_write(&ctx->state_sema);
 	}

 	spu_del_wq(wq, &wait, prio);
 }

 static void spu_prio_wakeup(void)
 {
 	int best = sched_find_first_bit(spu_prio->bitmap);
 	if (best < MAX_PRIO) {
 		wait_queue_head_t *wq = &spu_prio->waitq[best];
 		wake_up_interruptible_nr(wq, 1);
 	}
 }

 static int get_active_spu(struct spu *spu)
 {
 	int node = spu->node;
 	struct spu *tmp;
 	int rc = 0;

 	mutex_lock(&spu_prio->active_mutex[node]);
 	list_for_each_entry(tmp, &spu_prio->active_list[node], list) {
 		if (tmp == spu) {
 			list_del_init(&spu->list);
 			rc = 1;
 			break;
 		}
 	}
 	mutex_unlock(&spu_prio->active_mutex[node]);
 	return rc;
 }

 static void put_active_spu(struct spu *spu)
 {
 	int node = spu->node;

 	mutex_lock(&spu_prio->active_mutex[node]);
 	list_add_tail(&spu->list, &spu_prio->active_list[node]);
 	mutex_unlock(&spu_prio->active_mutex[node]);
 }

 static struct spu *spu_get_idle(struct spu_context *ctx, u64 flags)
 {
 	struct spu *spu = NULL;
 	int node = cpu_to_node(raw_smp_processor_id());
 	int n;

 	for (n = 0; n < MAX_NUMNODES; n++, node++) {
 		node = (node < MAX_NUMNODES) ? node : 0;
 		if (!node_allowed(node))
 			continue;
 		spu = spu_alloc_node(node);
 		if (spu)
 			break;
 	}
 	return spu;
 }

 static inline struct spu *spu_get(struct spu_context *ctx, u64 flags)
 {
 	/* Future: spu_get_idle() if possible,
 	 * otherwise try to preempt an active
 	 * context.
 	 */
 	return spu_get_idle(ctx, flags);
 }

 /* The three externally callable interfaces
  * for the scheduler begin here.
  *
  *	spu_activate	- bind a context to SPU, waiting as needed.
  *	spu_deactivate	- unbind a context from its SPU.
  *	spu_yield	- yield an SPU if others are waiting.
  */

 int spu_activate(struct spu_context *ctx, u64 flags)
 {
 	struct spu *spu;
 	int ret = 0;

 	for (;;) {
 		if (ctx->spu)
 			return 0;
 		spu = spu_get(ctx, flags);
 		if (spu != NULL) {
 			if (ctx->spu != NULL) {
 				spu_free(spu);
 				spu_prio_wakeup();
 				break;
 			}
 			bind_context(spu, ctx);
 			put_active_spu(spu);
 			break;
 		}
 		spu_prio_wait(ctx, flags);
 		if (signal_pending(current)) {
 			ret = -ERESTARTSYS;
 			spu_prio_wakeup();
 			break;
 		}
 	}
 	return ret;
 }

 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) {
 		spu_free(spu);
 		spu_prio_wakeup();
 	}
 }

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

 	if (down_write_trylock(&ctx->state_sema)) {
 		if ((spu = ctx->spu) != NULL) {
 			int best = sched_find_first_bit(spu_prio->bitmap);
 			if (best < MAX_PRIO) {
 				pr_debug("%s: yielding SPU %d NODE %d\n",
 					 __FUNCTION__, spu->number, spu->node);
 				spu_deactivate(ctx);
 				ctx->state = SPU_STATE_SAVED;
 				need_yield = 1;
 			} else {
 				spu->prio = MAX_PRIO;
 			}
 		}
 		up_write(&ctx->state_sema);
 	}
 	if (unlikely(need_yield))
 		yield();
 }

 int __init spu_sched_init(void)
 {
 	int i;

 	spu_prio = kzalloc(sizeof(struct spu_prio_array), GFP_KERNEL);
 	if (!spu_prio) {
 		printk(KERN_WARNING "%s: Unable to allocate priority queue.\n",
 		       __FUNCTION__);
 		return 1;
 	}
 	for (i = 0; i < MAX_PRIO; i++) {
 		init_waitqueue_head(&spu_prio->waitq[i]);
 		__clear_bit(i, spu_prio->bitmap);
 	}
 	__set_bit(MAX_PRIO, spu_prio->bitmap);
 	for (i = 0; i < MAX_NUMNODES; i++) {
 		mutex_init(&spu_prio->active_mutex[i]);
 		INIT_LIST_HEAD(&spu_prio->active_list[i]);
 	}
 	return 0;
 }

 void __exit spu_sched_exit(void)
 {
 	struct spu *spu, *tmp;
 	int node;

 	for (node = 0; node < MAX_NUMNODES; node++) {
 		mutex_lock(&spu_prio->active_mutex[node]);
 		list_for_each_entry_safe(spu, tmp, &spu_prio->active_list[node],
 					 list) {
 			list_del_init(&spu->list);
 			spu_free(spu);
 		}
 		mutex_unlock(&spu_prio->active_mutex[node]);
 	}
 	kfree(spu_prio);
 }
	/* sched.c - SPU scheduler.
	*
	* Copyright (C) IBM 2005
	* Author: Mark Nutter <mnutter@us.ibm.com>
	*
	* 2006-03-31 NUMA domains added.
	*
	* 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/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 <linux/numa.h>
	#include <linux/mutex.h>
	#include <linux/notifier.h>

	#include <asm/io.h>
	#include <asm/mmu_context.h>
	#include <asm/spu.h>
	#include <asm/spu_csa.h>
	#include <asm/spu_priv1.h>
	#include "spufs.h"

	#define SPU_MIN_TIMESLICE (100 * HZ / 1000)

	#define SPU_BITMAP_SIZE (((MAX_PRIO+BITS_PER_LONG)/BITS_PER_LONG)+1)
	struct spu_prio_array {
	unsigned long bitmap[SPU_BITMAP_SIZE];
	wait_queue_head_t waitq[MAX_PRIO];
	struct list_head active_list[MAX_NUMNODES];
	struct mutex active_mutex[MAX_NUMNODES];
	};

	static struct spu_prio_array *spu_prio;

	static inline int node_allowed(int node)
	{
	cpumask_t mask;

	if (!nr_cpus_node(node))
	return 0;
	mask = node_to_cpumask(node);
	if (!cpus_intersects(mask, current->cpus_allowed))
	return 0;
	return 1;
	}

	static inline void mm_needs_global_tlbie(struct mm_struct *mm)
	{
	int nr = (NR_CPUS > 1) ? NR_CPUS : NR_CPUS + 1;

	/* Global TLBIE broadcast required with SPEs. */
	__cpus_setall(&mm->cpu_vm_mask, nr);
	}

	static BLOCKING_NOTIFIER_HEAD(spu_switch_notifier);

	static void spu_switch_notify(struct spu spu, struct spu_context ctx)
	{
	blocking_notifier_call_chain(&spu_switch_notifier,
	ctx ? ctx->object_id : 0, spu);
	}

	int spu_switch_event_register(struct notifier_block * n)
	{
	return blocking_notifier_chain_register(&spu_switch_notifier, n);
	}

	int spu_switch_event_unregister(struct notifier_block * n)
	{
	return blocking_notifier_chain_unregister(&spu_switch_notifier, n);
	}


	static inline void bind_context(struct spu spu, struct spu_context ctx)
	{
	pr_debug("%s: pid=%d SPU=%d NODE=%d\n", __FUNCTION__, current->pid,
	spu->number, spu->node);
	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;
	spu->mfc_callback = spufs_mfc_callback;
	spu->dma_callback = spufs_dma_callback;
	mb();
	spu_unmap_mappings(ctx);
	spu_restore(&ctx->csa, spu);
	spu->timestamp = jiffies;
	spu_cpu_affinity_set(spu, raw_smp_processor_id());
	spu_switch_notify(spu, ctx);
	}

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

	static inline void spu_add_wq(wait_queue_head_t * wq, wait_queue_t * wait,
	int prio)
	{
	prepare_to_wait_exclusive(wq, wait, TASK_INTERRUPTIBLE);
	set_bit(prio, spu_prio->bitmap);
	}

	static inline void spu_del_wq(wait_queue_head_t * wq, wait_queue_t * wait,
	int prio)
	{
	u64 flags;

	__set_current_state(TASK_RUNNING);

	spin_lock_irqsave(&wq->lock, flags);

	remove_wait_queue_locked(wq, wait);
	if (list_empty(&wq->task_list))
	clear_bit(prio, spu_prio->bitmap);

	spin_unlock_irqrestore(&wq->lock, flags);
	}

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

	if (ctx->spu)
	return;

	spu_add_wq(wq, &wait, prio);

	if (!signal_pending(current)) {
	up_write(&ctx->state_sema);
	pr_debug("%s: pid=%d prio=%d\n", __FUNCTION__,
	current->pid, current->prio);
	schedule();
	down_write(&ctx->state_sema);
	}

	spu_del_wq(wq, &wait, prio);
	}

	static void spu_prio_wakeup(void)
	{
	int best = sched_find_first_bit(spu_prio->bitmap);
	if (best < MAX_PRIO) {
	wait_queue_head_t *wq = &spu_prio->waitq[best];
	wake_up_interruptible_nr(wq, 1);
	}
	}

	static int get_active_spu(struct spu *spu)
	{
	int node = spu->node;
	struct spu *tmp;
	int rc = 0;

	mutex_lock(&spu_prio->active_mutex[node]);
	list_for_each_entry(tmp, &spu_prio->active_list[node], list) {
	if (tmp == spu) {
	list_del_init(&spu->list);
	rc = 1;
	break;
	}
	}
	mutex_unlock(&spu_prio->active_mutex[node]);
	return rc;
	}

	static void put_active_spu(struct spu *spu)
	{
	int node = spu->node;

	mutex_lock(&spu_prio->active_mutex[node]);
	list_add_tail(&spu->list, &spu_prio->active_list[node]);
	mutex_unlock(&spu_prio->active_mutex[node]);
	}

	static struct spu spu_get_idle(struct spu_context ctx, u64 flags)
	{
	struct spu *spu = NULL;
	int node = cpu_to_node(raw_smp_processor_id());
	int n;

	for (n = 0; n < MAX_NUMNODES; n++, node++) {
	node = (node < MAX_NUMNODES) ? node : 0;
	if (!node_allowed(node))
	continue;
	spu = spu_alloc_node(node);
	if (spu)
	break;
	}
	return spu;
	}

	static inline struct spu spu_get(struct spu_context ctx, u64 flags)
	{
	/* Future: spu_get_idle() if possible,
	* otherwise try to preempt an active
	* context.
	*/
	return spu_get_idle(ctx, flags);
	}

	/* The three externally callable interfaces
	* for the scheduler begin here.
	*
	* spu_activate - bind a context to SPU, waiting as needed.
	* spu_deactivate - unbind a context from its SPU.
	* spu_yield - yield an SPU if others are waiting.
	*/

	int spu_activate(struct spu_context *ctx, u64 flags)
	{
	struct spu *spu;
	int ret = 0;

	for (;;) {
	if (ctx->spu)
	return 0;
	spu = spu_get(ctx, flags);
	if (spu != NULL) {
	if (ctx->spu != NULL) {
	spu_free(spu);
	spu_prio_wakeup();
	break;
	}
	bind_context(spu, ctx);
	put_active_spu(spu);
	break;
	}
	spu_prio_wait(ctx, flags);
	if (signal_pending(current)) {
	ret = -ERESTARTSYS;
	spu_prio_wakeup();
	break;
	}
	}
	return ret;
	}

	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) {
	spu_free(spu);
	spu_prio_wakeup();
	}
	}

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

	if (down_write_trylock(&ctx->state_sema)) {
	if ((spu = ctx->spu) != NULL) {
	int best = sched_find_first_bit(spu_prio->bitmap);
	if (best < MAX_PRIO) {
	pr_debug("%s: yielding SPU %d NODE %d\n",
	__FUNCTION__, spu->number, spu->node);
	spu_deactivate(ctx);
	ctx->state = SPU_STATE_SAVED;
	need_yield = 1;
	} else {
	spu->prio = MAX_PRIO;
	}
	}
	up_write(&ctx->state_sema);
	}
	if (unlikely(need_yield))
	yield();
	}

	int __init spu_sched_init(void)
	{
	int i;

	spu_prio = kzalloc(sizeof(struct spu_prio_array), GFP_KERNEL);
	if (!spu_prio) {
	printk(KERN_WARNING "%s: Unable to allocate priority queue.\n",
	__FUNCTION__);
	return 1;
	}
	for (i = 0; i < MAX_PRIO; i++) {
	init_waitqueue_head(&spu_prio->waitq[i]);
	__clear_bit(i, spu_prio->bitmap);
	}
	__set_bit(MAX_PRIO, spu_prio->bitmap);
	for (i = 0; i < MAX_NUMNODES; i++) {
	mutex_init(&spu_prio->active_mutex[i]);
	INIT_LIST_HEAD(&spu_prio->active_list[i]);
	}
	return 0;
	}

	void __exit spu_sched_exit(void)
	{
	struct spu spu, tmp;
	int node;

	for (node = 0; node < MAX_NUMNODES; node++) {
	mutex_lock(&spu_prio->active_mutex[node]);
	list_for_each_entry_safe(spu, tmp, &spu_prio->active_list[node],
	list) {
	list_del_init(&spu->list);
	spu_free(spu);
	}
	mutex_unlock(&spu_prio->active_mutex[node]);
	}
	kfree(spu_prio);
	}