linux/arch/powerpc/platforms/cell/spufs/sched.c

368 lines
8.4 KiB
C

/* 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);
}