#include <asm/spu_priv1.h>
#include "spufs.h"
-#define SPU_MIN_TIMESLICE (100 * HZ / 1000)
+#define SPU_TIMESLICE (HZ)
-#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];
+ DECLARE_BITMAP(bitmap, MAX_PRIO);
+ struct list_head runq[MAX_PRIO];
+ spinlock_t runq_lock;
struct list_head active_list[MAX_NUMNODES];
struct mutex active_mutex[MAX_NUMNODES];
};
static struct spu_prio_array *spu_prio;
+static struct workqueue_struct *spu_sched_wq;
static inline int node_allowed(int node)
{
return 1;
}
+void spu_start_tick(struct spu_context *ctx)
+{
+ if (ctx->policy == SCHED_RR) {
+ /*
+ * Make sure the exiting bit is cleared.
+ */
+ clear_bit(SPU_SCHED_EXITING, &ctx->sched_flags);
+ mb();
+ queue_delayed_work(spu_sched_wq, &ctx->sched_work, SPU_TIMESLICE);
+ }
+}
+
+void spu_stop_tick(struct spu_context *ctx)
+{
+ if (ctx->policy == SCHED_RR) {
+ /*
+ * While the work can be rearming normally setting this flag
+ * makes sure it does not rearm itself anymore.
+ */
+ set_bit(SPU_SCHED_EXITING, &ctx->sched_flags);
+ mb();
+ cancel_delayed_work(&ctx->sched_work);
+ }
+}
+
+void spu_sched_tick(struct work_struct *work)
+{
+ struct spu_context *ctx =
+ container_of(work, struct spu_context, sched_work.work);
+ struct spu *spu;
+ int preempted = 0;
+
+ /*
+ * If this context is being stopped avoid rescheduling from the
+ * scheduler tick because we would block on the state_mutex.
+ * The caller will yield the spu later on anyway.
+ */
+ if (test_bit(SPU_SCHED_EXITING, &ctx->sched_flags))
+ return;
+
+ mutex_lock(&ctx->state_mutex);
+ spu = ctx->spu;
+ if (spu) {
+ int best = sched_find_first_bit(spu_prio->bitmap);
+ if (best <= ctx->prio) {
+ spu_deactivate(ctx);
+ preempted = 1;
+ }
+ }
+ mutex_unlock(&ctx->state_mutex);
+
+ if (preempted) {
+ /*
+ * We need to break out of the wait loop in spu_run manually
+ * to ensure this context gets put on the runqueue again
+ * ASAP.
+ */
+ wake_up(&ctx->stop_wq);
+ } else
+ spu_start_tick(ctx);
+}
+
/**
* spu_add_to_active_list - add spu to active list
* @spu: spu to add to the active list
/**
* spu_remove_from_active_list - remove spu from active list
* @spu: spu to remove from the active list
- *
- * This function removes an spu from the active list. If the spu was
- * found on the active list the function returns 1, else it doesn't do
- * anything and returns 0.
*/
-static int spu_remove_from_active_list(struct spu *spu)
+static void spu_remove_from_active_list(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;
- }
- }
+ list_del_init(&spu->list);
mutex_unlock(&spu_prio->active_mutex[node]);
- return rc;
-}
-
-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);
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_associate_mm(spu, ctx->owner);
spu->ibox_callback = spufs_ibox_callback;
spu->wbox_callback = spufs_wbox_callback;
spu->stop_callback = spufs_stop_callback;
* spu_unbind_context - unbind spu context from physical spu
* @spu: physical spu to unbind from
* @ctx: context to unbind
- *
- * If the spu was on the active list the function returns 1, else 0.
*/
-static int spu_unbind_context(struct spu *spu, struct spu_context *ctx)
+static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
{
- int was_active = spu_remove_from_active_list(spu);
-
pr_debug("%s: unbind pid=%d SPU=%d NODE=%d\n", __FUNCTION__,
spu->pid, spu->number, spu->node);
+ spu_remove_from_active_list(spu);
spu_switch_notify(spu, NULL);
spu_unmap_mappings(ctx);
spu_save(&ctx->csa, spu);
spu->stop_callback = NULL;
spu->mfc_callback = NULL;
spu->dma_callback = NULL;
- spu->mm = NULL;
+ spu_associate_mm(spu, NULL);
spu->pid = 0;
- spu->prio = MAX_PRIO;
ctx->ops = &spu_backing_ops;
ctx->spu = NULL;
spu->flags = 0;
spu->ctx = NULL;
-
- return was_active;
}
-static inline void spu_add_wq(wait_queue_head_t * wq, wait_queue_t * wait,
- int prio)
+/**
+ * spu_add_to_rq - add a context to the runqueue
+ * @ctx: context to add
+ */
+static void __spu_add_to_rq(struct spu_context *ctx)
{
- prepare_to_wait_exclusive(wq, wait, TASK_INTERRUPTIBLE);
+ int prio = ctx->prio;
+
+ list_add_tail(&ctx->rq, &spu_prio->runq[prio]);
set_bit(prio, spu_prio->bitmap);
}
-static inline void spu_del_wq(wait_queue_head_t * wq, wait_queue_t * wait,
- int prio)
+static void __spu_del_from_rq(struct spu_context *ctx)
{
- u64 flags;
-
- __set_current_state(TASK_RUNNING);
-
- spin_lock_irqsave(&wq->lock, flags);
+ int prio = ctx->prio;
- remove_wait_queue_locked(wq, wait);
- if (list_empty(&wq->task_list))
+ if (!list_empty(&ctx->rq))
+ list_del_init(&ctx->rq);
+ if (list_empty(&spu_prio->runq[prio]))
clear_bit(prio, spu_prio->bitmap);
-
- spin_unlock_irqrestore(&wq->lock, flags);
}
-static void spu_prio_wait(struct spu_context *ctx, u64 flags)
+static void spu_prio_wait(struct spu_context *ctx)
{
- 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);
-
+ spin_lock(&spu_prio->runq_lock);
+ prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE);
if (!signal_pending(current)) {
+ __spu_add_to_rq(ctx);
+ spin_unlock(&spu_prio->runq_lock);
mutex_unlock(&ctx->state_mutex);
- pr_debug("%s: pid=%d prio=%d\n", __FUNCTION__,
- current->pid, current->prio);
schedule();
mutex_lock(&ctx->state_mutex);
+ spin_lock(&spu_prio->runq_lock);
+ __spu_del_from_rq(ctx);
}
-
- spu_del_wq(wq, &wait, prio);
+ spin_unlock(&spu_prio->runq_lock);
+ __set_current_state(TASK_RUNNING);
+ remove_wait_queue(&ctx->stop_wq, &wait);
}
-static void spu_prio_wakeup(void)
+/**
+ * spu_reschedule - try to find a runnable context for a spu
+ * @spu: spu available
+ *
+ * This function is called whenever a spu becomes idle. It looks for the
+ * most suitable runnable spu context and schedules it for execution.
+ */
+static void spu_reschedule(struct spu *spu)
{
- int best = sched_find_first_bit(spu_prio->bitmap);
+ int best;
+
+ spu_free(spu);
+
+ spin_lock(&spu_prio->runq_lock);
+ 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);
+ struct list_head *rq = &spu_prio->runq[best];
+ struct spu_context *ctx;
+
+ BUG_ON(list_empty(rq));
+
+ ctx = list_entry(rq->next, struct spu_context, rq);
+ __spu_del_from_rq(ctx);
+ wake_up(&ctx->stop_wq);
}
+ spin_unlock(&spu_prio->runq_lock);
}
-static struct spu *spu_get_idle(struct spu_context *ctx, u64 flags)
+static struct spu *spu_get_idle(struct spu_context *ctx)
{
struct spu *spu = NULL;
int node = cpu_to_node(raw_smp_processor_id());
return spu;
}
-static inline struct spu *spu_get(struct spu_context *ctx, u64 flags)
+/**
+ * find_victim - find a lower priority context to preempt
+ * @ctx: canidate context for running
+ *
+ * Returns the freed physical spu to run the new context on.
+ */
+static struct spu *find_victim(struct spu_context *ctx)
{
- /* Future: spu_get_idle() if possible,
- * otherwise try to preempt an active
- * context.
+ struct spu_context *victim = NULL;
+ struct spu *spu;
+ int node, n;
+
+ /*
+ * Look for a possible preemption candidate on the local node first.
+ * If there is no candidate look at the other nodes. This isn't
+ * exactly fair, but so far the whole spu schedule tries to keep
+ * a strong node affinity. We might want to fine-tune this in
+ * the future.
*/
- return spu_get_idle(ctx, flags);
+ restart:
+ node = cpu_to_node(raw_smp_processor_id());
+ for (n = 0; n < MAX_NUMNODES; n++, node++) {
+ node = (node < MAX_NUMNODES) ? node : 0;
+ if (!node_allowed(node))
+ continue;
+
+ mutex_lock(&spu_prio->active_mutex[node]);
+ list_for_each_entry(spu, &spu_prio->active_list[node], list) {
+ struct spu_context *tmp = spu->ctx;
+
+ if (tmp->rt_priority < ctx->rt_priority &&
+ (!victim || tmp->rt_priority < victim->rt_priority))
+ victim = spu->ctx;
+ }
+ mutex_unlock(&spu_prio->active_mutex[node]);
+
+ if (victim) {
+ /*
+ * This nests ctx->state_mutex, but we always lock
+ * higher priority contexts before lower priority
+ * ones, so this is safe until we introduce
+ * priority inheritance schemes.
+ */
+ if (!mutex_trylock(&victim->state_mutex)) {
+ victim = NULL;
+ goto restart;
+ }
+
+ spu = victim->spu;
+ if (!spu) {
+ /*
+ * This race can happen because we've dropped
+ * the active list mutex. No a problem, just
+ * restart the search.
+ */
+ mutex_unlock(&victim->state_mutex);
+ victim = NULL;
+ goto restart;
+ }
+ spu_unbind_context(spu, victim);
+ mutex_unlock(&victim->state_mutex);
+ /*
+ * We need to break out of the wait loop in spu_run
+ * manually to ensure this context gets put on the
+ * runqueue again ASAP.
+ */
+ wake_up(&victim->stop_wq);
+ return spu;
+ }
+ }
+
+ return NULL;
}
-/* The three externally callable interfaces
- * for the scheduler begin here.
+/**
+ * spu_activate - find a free spu for a context and execute it
+ * @ctx: spu context to schedule
+ * @flags: flags (currently ignored)
*
- * 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.
+ * Tries to find a free spu to run @ctx. If no free spu is available
+ * add the context to the runqueue so it gets woken up once an spu
+ * is available.
*/
-
-int spu_activate(struct spu_context *ctx, u64 flags)
+int spu_activate(struct spu_context *ctx, unsigned long 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;
- }
+ if (ctx->spu)
+ return 0;
+
+ do {
+ struct spu *spu;
+
+ spu = spu_get_idle(ctx);
+ /*
+ * If this is a realtime thread we try to get it running by
+ * preempting a lower priority thread.
+ */
+ if (!spu && ctx->rt_priority)
+ spu = find_victim(ctx);
+ if (spu) {
spu_bind_context(spu, ctx);
- break;
- }
- spu_prio_wait(ctx, flags);
- if (signal_pending(current)) {
- ret = -ERESTARTSYS;
- spu_prio_wakeup();
- break;
+ return 0;
}
- }
- return ret;
+
+ spu_prio_wait(ctx);
+ } while (!signal_pending(current));
+
+ return -ERESTARTSYS;
}
+/**
+ * spu_deactivate - unbind a context from it's physical spu
+ * @ctx: spu context to unbind
+ *
+ * Unbind @ctx from the physical spu it is running on and schedule
+ * the highest priority context to run on the freed physical spu.
+ */
void spu_deactivate(struct spu_context *ctx)
{
- struct spu *spu;
- int was_active;
+ struct spu *spu = ctx->spu;
- spu = ctx->spu;
- if (!spu)
- return;
- was_active = spu_unbind_context(spu, ctx);
- if (was_active) {
- spu_free(spu);
- spu_prio_wakeup();
+ if (spu) {
+ spu_unbind_context(spu, ctx);
+ spu_reschedule(spu);
}
}
+/**
+ * spu_yield - yield a physical spu if others are waiting
+ * @ctx: spu context to yield
+ *
+ * Check if there is a higher priority context waiting and if yes
+ * unbind @ctx from the physical spu and schedule the highest
+ * priority context to run on the freed physical spu instead.
+ */
void spu_yield(struct spu_context *ctx)
{
struct spu *spu;
- int need_yield = 0;
if (mutex_trylock(&ctx->state_mutex)) {
if ((spu = ctx->spu) != NULL) {
pr_debug("%s: yielding SPU %d NODE %d\n",
__FUNCTION__, spu->number, spu->node);
spu_deactivate(ctx);
- need_yield = 1;
- } else {
- spu->prio = MAX_PRIO;
}
}
mutex_unlock(&ctx->state_mutex);
}
- if (unlikely(need_yield))
- yield();
}
int __init spu_sched_init(void)
{
int i;
+ spu_sched_wq = create_singlethread_workqueue("spusched");
+ if (!spu_sched_wq)
+ return 1;
+
spu_prio = kzalloc(sizeof(struct spu_prio_array), GFP_KERNEL);
if (!spu_prio) {
printk(KERN_WARNING "%s: Unable to allocate priority queue.\n",
__FUNCTION__);
+ destroy_workqueue(spu_sched_wq);
return 1;
}
for (i = 0; i < MAX_PRIO; i++) {
- init_waitqueue_head(&spu_prio->waitq[i]);
+ INIT_LIST_HEAD(&spu_prio->runq[i]);
__clear_bit(i, spu_prio->bitmap);
}
__set_bit(MAX_PRIO, spu_prio->bitmap);
mutex_init(&spu_prio->active_mutex[i]);
INIT_LIST_HEAD(&spu_prio->active_list[i]);
}
+ spin_lock_init(&spu_prio->runq_lock);
return 0;
}
mutex_unlock(&spu_prio->active_mutex[node]);
}
kfree(spu_prio);
+ destroy_workqueue(spu_sched_wq);
}
projects / linux-2.6 / blobdiff