[PATCH] drm/amdkfd: fix cp hang in eviction

[Huang, JinHuiEric]

ping.

On 2019-07-10 11:20 a.m., Huang, JinHuiEric wrote:
> The cp hang occurs in OCL conformance test only on supermicro
> platform which has 40 cores and the test generates 40 threads.
> The root cause is race condition in non-protected flags.
>
> The fix is to add flags of is_evicted and is_active(init_mqd())
> into protected area.
>
> Signed-off-by: Eric Huang <JinhuiEric.Huang at amd.com>
> ---
>   drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c | 16 +++++++++-------
>   1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> index 9ffdda5..f23e17b 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> @@ -1157,12 +1157,7 @@ static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
>   
>   	mqd_mgr = dqm->mqd_mgrs[get_mqd_type_from_queue_type(
>   			q->properties.type)];
> -	/*
> -	 * Eviction state logic: mark all queues as evicted, even ones
> -	 * not currently active. Restoring inactive queues later only
> -	 * updates the is_evicted flag but is a no-op otherwise.
> -	 */
> -	q->properties.is_evicted = !!qpd->evicted;
> +
>   	if (q->properties.type == KFD_QUEUE_TYPE_SDMA ||
>   		q->properties.type == KFD_QUEUE_TYPE_SDMA_XGMI)
>   		dqm->asic_ops.init_sdma_vm(dqm, q, qpd);
> @@ -1173,9 +1168,16 @@ static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
>   		retval = -ENOMEM;
>   		goto out_deallocate_doorbell;
>   	}
> +
> +	dqm_lock(dqm);
> +	/*
> +	 * Eviction state logic: mark all queues as evicted, even ones
> +	 * not currently active. Restoring inactive queues later only
> +	 * updates the is_evicted flag but is a no-op otherwise.
> +	 */
> +	q->properties.is_evicted = !!qpd->evicted;
>   	mqd_mgr->init_mqd(mqd_mgr, &q->mqd, q->mqd_mem_obj,
>   				&q->gart_mqd_addr, &q->properties);
> -	dqm_lock(dqm);
>   
>   	list_add(&q->list, &qpd->queues_list);
>   	qpd->queue_count++;