From 4e0f4ed0df71013290cd2a01f7b84264f7b99678 Mon Sep 17 00:00:00 2001 From: Luke Browning Date: Mon, 23 Apr 2007 21:08:13 +0200 Subject: [PATCH] [POWERPC] spu sched: make addition to stop_wq and runque atomic vs wakeup 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 Signed-off-by: Christoph Hellwig Signed-off-by: Arnd Bergmann --- arch/powerpc/platforms/cell/spufs/sched.c | 38 ++++++++++------------- 1 file changed, 16 insertions(+), 22 deletions(-) diff --git a/arch/powerpc/platforms/cell/spufs/sched.c b/arch/powerpc/platforms/cell/spufs/sched.c index 876828cc95a..91030b8abdc 100644 --- a/arch/powerpc/platforms/cell/spufs/sched.c +++ b/arch/powerpc/platforms/cell/spufs/sched.c @@ -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 * @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); - list_add_tail(&ctx->rq, &spu_prio->runq[ctx->prio]); - set_bit(ctx->prio, spu_prio->bitmap); - mb(); - spin_unlock(&spu_prio->runq_lock); + int prio = ctx->prio; + + list_add_tail(&ctx->rq, &spu_prio->runq[prio]); + set_bit(prio, spu_prio->bitmap); } -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)) 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 - */ -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); + clear_bit(prio, spu_prio->bitmap); } static void spu_prio_wait(struct spu_context *ctx) { DEFINE_WAIT(wait); + 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); schedule(); 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); remove_wait_queue(&ctx->stop_wq, &wait); } @@ -300,7 +296,7 @@ static void spu_reschedule(struct spu *spu) BUG_ON(list_empty(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); } spin_unlock(&spu_prio->runq_lock); @@ -427,9 +423,7 @@ int spu_activate(struct spu_context *ctx, unsigned long flags) return 0; } - spu_add_to_rq(ctx); spu_prio_wait(ctx); - spu_del_from_rq(ctx); } while (!signal_pending(current)); return -ERESTARTSYS; -- 2.20.1