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[POWERPC] spu sched: make addition to stop_wq and runque atomic vs wakeup

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Addition to stop_wq needs to happen before adding to the runqeueue and
under the same lock so that we don't have a race window for a lost
wake up in the spu scheduler.

Signed-off-by: Luke Browning <lukebrowning@us.ibm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
This commit is contained in:
Luke Browning 2007-04-23 21:08:13 +02:00 committed by Arnd Bergmann
parent 7ec18ab923
commit 4e0f4ed0df
1 changed files with 16 additions and 22 deletions
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38
arch/powerpc/platforms/cell/spufs/sched.c
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@ -236,44 +236,40 @@ static void spu_unbind_context(struct spu *spu, struct spu_context *ctx)
* spu_add_to_rq - add a context to the runqueue * spu_add_to_rq - add a context to the runqueue
* @ctx: context to add * @ctx: context to add
*/ */
static void spu_add_to_rq(struct spu_context *ctx) static void __spu_add_to_rq(struct spu_context *ctx)
{ {
spin_lock(&spu_prio->runq_lock); int prio = ctx->prio;
list_add_tail(&ctx->rq, &spu_prio->runq[ctx->prio]);
set_bit(ctx->prio, spu_prio->bitmap); list_add_tail(&ctx->rq, &spu_prio->runq[prio]);
mb(); set_bit(prio, spu_prio->bitmap);
spin_unlock(&spu_prio->runq_lock);
} }
static void __spu_del_from_rq(struct spu_context *ctx, int prio) static void __spu_del_from_rq(struct spu_context *ctx)
{ {
int prio = ctx->prio;
if (!list_empty(&ctx->rq)) if (!list_empty(&ctx->rq))
list_del_init(&ctx->rq); list_del_init(&ctx->rq);
if (list_empty(&spu_prio->runq[prio])) if (list_empty(&spu_prio->runq[prio]))
clear_bit(ctx->prio, spu_prio->bitmap); clear_bit(prio, spu_prio->bitmap);
}
/**
* spu_del_from_rq - remove a context from the runqueue
* @ctx: context to remove
*/
static void spu_del_from_rq(struct spu_context *ctx)
{
spin_lock(&spu_prio->runq_lock);
__spu_del_from_rq(ctx, ctx->prio);
spin_unlock(&spu_prio->runq_lock);
} }
static void spu_prio_wait(struct spu_context *ctx) static void spu_prio_wait(struct spu_context *ctx)
{ {
DEFINE_WAIT(wait); DEFINE_WAIT(wait);
spin_lock(&spu_prio->runq_lock);
prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE); prepare_to_wait_exclusive(&ctx->stop_wq, &wait, TASK_INTERRUPTIBLE);
if (!signal_pending(current)) { if (!signal_pending(current)) {
__spu_add_to_rq(ctx);
spin_unlock(&spu_prio->runq_lock);
mutex_unlock(&ctx->state_mutex); mutex_unlock(&ctx->state_mutex);
schedule(); schedule();
mutex_lock(&ctx->state_mutex); mutex_lock(&ctx->state_mutex);
spin_lock(&spu_prio->runq_lock);
__spu_del_from_rq(ctx);
} }
spin_unlock(&spu_prio->runq_lock);
__set_current_state(TASK_RUNNING); __set_current_state(TASK_RUNNING);
remove_wait_queue(&ctx->stop_wq, &wait); remove_wait_queue(&ctx->stop_wq, &wait);
} }
@ -300,7 +296,7 @@ static void spu_reschedule(struct spu *spu)
BUG_ON(list_empty(rq)); BUG_ON(list_empty(rq));
ctx = list_entry(rq->next, struct spu_context, rq); ctx = list_entry(rq->next, struct spu_context, rq);
__spu_del_from_rq(ctx, best); __spu_del_from_rq(ctx);
wake_up(&ctx->stop_wq); wake_up(&ctx->stop_wq);
} }
spin_unlock(&spu_prio->runq_lock); spin_unlock(&spu_prio->runq_lock);
@ -427,9 +423,7 @@ int spu_activate(struct spu_context *ctx, unsigned long flags)
return 0; return 0;
} }
spu_add_to_rq(ctx);
spu_prio_wait(ctx); spu_prio_wait(ctx);
spu_del_from_rq(ctx);
} while (!signal_pending(current)); } while (!signal_pending(current));
return -ERESTARTSYS; return -ERESTARTSYS;