diff options
Diffstat (limited to 'arch/powerpc/platforms/cell/spufs/sched.c')
-rw-r--r-- | arch/powerpc/platforms/cell/spufs/sched.c | 386 |
1 files changed, 267 insertions, 119 deletions
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c index bd6fe4b..2f25e68 100644 --- a/arch/powerpc/platforms/cell/spufs/sched.c +++ b/arch/powerpc/platforms/cell/spufs/sched.c @@ -44,17 +44,18 @@ #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) { @@ -68,6 +69,64 @@ static inline int node_allowed(int node) return 1; } +void spu_start_tick(struct spu_context *ctx) +{ + if (ctx->policy == SCHED_RR) + queue_delayed_work(spu_sched_wq, &ctx->sched_work, SPU_TIMESLICE); +} + +void spu_stop_tick(struct spu_context *ctx) +{ + if (ctx->policy == SCHED_RR) + 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 rearm = 1; + + 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); + rearm = 0; + } + } + mutex_unlock(&ctx->state_mutex); + + if (rearm) + spu_start_tick(ctx); +} + +/** + * spu_add_to_active_list - add spu to active list + * @spu: spu to add to the active list + */ +static void spu_add_to_active_list(struct spu *spu) +{ + mutex_lock(&spu_prio->active_mutex[spu->node]); + list_add_tail(&spu->list, &spu_prio->active_list[spu->node]); + mutex_unlock(&spu_prio->active_mutex[spu->node]); +} + +/** + * spu_remove_from_active_list - remove spu from active list + * @spu: spu to remove from the active list + */ +static void spu_remove_from_active_list(struct spu *spu) +{ + int node = spu->node; + + mutex_lock(&spu_prio->active_mutex[node]); + list_del_init(&spu->list); + mutex_unlock(&spu_prio->active_mutex[node]); +} + static inline void mm_needs_global_tlbie(struct mm_struct *mm) { int nr = (NR_CPUS > 1) ? NR_CPUS : NR_CPUS + 1; @@ -94,8 +153,12 @@ 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) +/** + * spu_bind_context - bind spu context to physical spu + * @spu: physical spu to bind to + * @ctx: context to bind + */ +static void spu_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); @@ -104,7 +167,6 @@ static inline void bind_context(struct spu *spu, struct spu_context *ctx) 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; @@ -118,12 +180,21 @@ static inline void bind_context(struct spu *spu, struct spu_context *ctx) spu->timestamp = jiffies; spu_cpu_affinity_set(spu, raw_smp_processor_id()); spu_switch_notify(spu, ctx); + spu_add_to_active_list(spu); + ctx->state = SPU_STATE_RUNNABLE; } -static inline void unbind_context(struct spu *spu, struct spu_context *ctx) +/** + * spu_unbind_context - unbind spu context from physical spu + * @spu: physical spu to unbind from + * @ctx: context to unbind + */ +static void spu_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_remove_from_active_list(spu); spu_switch_notify(spu, NULL); spu_unmap_mappings(ctx); spu_save(&ctx->csa, spu); @@ -136,95 +207,98 @@ static inline void unbind_context(struct spu *spu, struct spu_context *ctx) 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) +/** + * 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); - set_bit(prio, spu_prio->bitmap); + spin_lock(&spu_prio->runq_lock); + list_add_tail(&ctx->rq, &spu_prio->runq[ctx->prio]); + set_bit(ctx->prio, spu_prio->bitmap); + spin_unlock(&spu_prio->runq_lock); } -static inline void spu_del_wq(wait_queue_head_t * wq, wait_queue_t * wait, - int prio) +/** + * spu_del_from_rq - remove a context from the runqueue + * @ctx: context to remove + */ +static void spu_del_from_rq(struct spu_context *ctx) { - u64 flags; - - __set_current_state(TASK_RUNNING); - - spin_lock_irqsave(&wq->lock, flags); + spin_lock(&spu_prio->runq_lock); + list_del_init(&ctx->rq); + if (list_empty(&spu_prio->runq[ctx->prio])) + clear_bit(ctx->prio, spu_prio->bitmap); + spin_unlock(&spu_prio->runq_lock); +} - remove_wait_queue_locked(wq, wait); - if (list_empty(&wq->task_list)) - clear_bit(prio, spu_prio->bitmap); +/** + * spu_grab_context - remove one context from the runqueue + * @prio: priority of the context to be removed + * + * This function removes one context from the runqueue for priority @prio. + * If there is more than one context with the given priority the first + * task on the runqueue will be taken. + * + * Returns the spu_context it just removed. + * + * Must be called with spu_prio->runq_lock held. + */ +static struct spu_context *spu_grab_context(int prio) +{ + struct list_head *rq = &spu_prio->runq[prio]; - spin_unlock_irqrestore(&wq->lock, flags); + if (list_empty(rq)) + return NULL; + return list_entry(rq->next, struct spu_context, rq); } -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); - + set_bit(SPU_SCHED_WAKE, &ctx->sched_flags); + prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE); if (!signal_pending(current)) { - up_write(&ctx->state_sema); - pr_debug("%s: pid=%d prio=%d\n", __FUNCTION__, - current->pid, current->prio); + mutex_unlock(&ctx->state_mutex); schedule(); - down_write(&ctx->state_sema); + mutex_lock(&ctx->state_mutex); } - - spu_del_wq(wq, &wait, prio); + __set_current_state(TASK_RUNNING); + remove_wait_queue(&ctx->stop_wq, &wait); + clear_bit(SPU_SCHED_WAKE, &ctx->sched_flags); } -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); - if (best < MAX_PRIO) { - wait_queue_head_t *wq = &spu_prio->waitq[best]; - wake_up_interruptible_nr(wq, 1); - } -} + int best; -static int get_active_spu(struct spu *spu) -{ - int node = spu->node; - struct spu *tmp; - int rc = 0; + spu_free(spu); - 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; - } + spin_lock(&spu_prio->runq_lock); + best = sched_find_first_bit(spu_prio->bitmap); + if (best < MAX_PRIO) { + struct spu_context *ctx = spu_grab_context(best); + if (ctx && test_bit(SPU_SCHED_WAKE, &ctx->sched_flags)) + wake_up(&ctx->stop_wq); } - 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]); + 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()); @@ -241,87 +315,154 @@ static struct spu *spu_get_idle(struct spu_context *ctx, u64 flags) 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); + 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 availble + * 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) + 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); 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; + + spu_add_to_rq(ctx); + if (!(flags & SPU_ACTIVATE_NOWAKE)) + spu_prio_wait(ctx); + spu_del_from_rq(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 needs_idle; + struct spu *spu = ctx->spu; - 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(); + 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 (down_write_trylock(&ctx->state_sema)) { + if (mutex_trylock(&ctx->state_mutex)) { 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); + mutex_unlock(&ctx->state_mutex); } if (unlikely(need_yield)) yield(); @@ -331,14 +472,19 @@ 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); @@ -346,6 +492,7 @@ int __init spu_sched_init(void) mutex_init(&spu_prio->active_mutex[i]); INIT_LIST_HEAD(&spu_prio->active_list[i]); } + spin_lock_init(&spu_prio->runq_lock); return 0; } @@ -364,4 +511,5 @@ void __exit spu_sched_exit(void) mutex_unlock(&spu_prio->active_mutex[node]); } kfree(spu_prio); + destroy_workqueue(spu_sched_wq); } |