[POWERPC] spufs: remove woken threads from the runqueue early
A single context should only be woken once, and we should not have
more wakeups for a given priority than the number of contexts on
that runqueue position.
Also add some asserts to trap future problems in this area more
easily.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c
index 1582d76..876828c 100644
--- a/arch/powerpc/platforms/cell/spufs/sched.c
+++ b/arch/powerpc/platforms/cell/spufs/sched.c
@@ -245,6 +245,14 @@
spin_unlock(&spu_prio->runq_lock);
}
+static void __spu_del_from_rq(struct spu_context *ctx, int prio)
+{
+ if (!list_empty(&ctx->rq))
+ list_del_init(&ctx->rq);
+ if (list_empty(&spu_prio->runq[prio]))
+ clear_bit(ctx->prio, spu_prio->bitmap);
+}
+
/**
* spu_del_from_rq - remove a context from the runqueue
* @ctx: context to remove
@@ -252,33 +260,10 @@
static void spu_del_from_rq(struct spu_context *ctx)
{
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);
+ __spu_del_from_rq(ctx, ctx->prio);
spin_unlock(&spu_prio->runq_lock);
}
-/**
- * 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];
-
- if (list_empty(rq))
- return NULL;
- return list_entry(rq->next, struct spu_context, rq);
-}
-
static void spu_prio_wait(struct spu_context *ctx)
{
DEFINE_WAIT(wait);
@@ -309,9 +294,14 @@
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)
- wake_up(&ctx->stop_wq);
+ 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, best);
+ wake_up(&ctx->stop_wq);
}
spin_unlock(&spu_prio->runq_lock);
}