Re: [dpdk-dev] [PATCH 08/21] vhost: iotlb: add pending miss request list and helpers

[Tiwei Bie <tiwei.bie@intel.com>]

On Thu, Aug 31, 2017 at 11:50:10AM +0200, Maxime Coquelin wrote:
> In order to be able to handle other ports or queues while waiting
> for an IOTLB miss reply, a pending list is created so that waiter
> can return and restart later on with sending again a miss request.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  lib/librte_vhost/iotlb.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++--
>  lib/librte_vhost/iotlb.h |  4 +++
>  lib/librte_vhost/vhost.h |  1 +
>  3 files changed, 91 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/librte_vhost/iotlb.c b/lib/librte_vhost/iotlb.c
> index 1b739dae5..d014bfe98 100644
> --- a/lib/librte_vhost/iotlb.c
> +++ b/lib/librte_vhost/iotlb.c
> @@ -49,7 +49,86 @@ struct vhost_iotlb_entry {
>  	uint8_t perm;
>  };
>  
> -#define IOTLB_CACHE_SIZE 1024
> +#define IOTLB_CACHE_SIZE 2048
> +
> +static void vhost_user_iotlb_pending_remove_all(struct vhost_virtqueue *vq)
> +{
> +	struct vhost_iotlb_entry *node, *temp_node;
> +
> +	rte_rwlock_write_lock(&vq->iotlb_lock);
> +
> +	TAILQ_FOREACH_SAFE(node, &vq->iotlb_pending_list, next, temp_node) {
> +		TAILQ_REMOVE(&vq->iotlb_pending_list, node, next);
> +		rte_mempool_put(vq->iotlb_pool, node);
> +	}
> +
> +	rte_rwlock_write_unlock(&vq->iotlb_lock);
> +}
> +
> +int vhost_user_iotlb_pending_miss(struct vhost_virtqueue *vq, uint64_t iova,
> +				uint8_t perm)
> +{
> +	struct vhost_iotlb_entry *node;
> +	int found = 0;
> +

The return value of this function is boolean. So it's better
to return bool instead of int.

> +	rte_rwlock_read_lock(&vq->iotlb_lock);
> +
> +	TAILQ_FOREACH(node, &vq->iotlb_pending_list, next) {
> +		if ((node->iova == iova) && (node->perm == perm)) {
> +			found = 1;
> +			break;
> +		}
> +	}
> +
> +	rte_rwlock_read_unlock(&vq->iotlb_lock);
> +
> +	return found;
> +}
> +
> +void vhost_user_iotlb_pending_insert(struct vhost_virtqueue *vq,
> +				uint64_t iova, uint8_t perm)
> +{
> +	struct vhost_iotlb_entry *node;
> +	int ret;
> +
> +	ret = rte_mempool_get(vq->iotlb_pool, (void **)&node);
> +	if (ret) {
> +		RTE_LOG(ERR, VHOST_CONFIG, "IOTLB pool empty, invalidate cache\n");

I think The log level should be INFO or the likes, not ERR.

> +		vhost_user_iotlb_pending_remove_all(vq);
> +		ret = rte_mempool_get(vq->iotlb_pool, (void **)&node);
> +		if (ret) {
> +			RTE_LOG(ERR, VHOST_CONFIG, "IOTLB pool still empty, failure\n");
> +			return;
> +		}
> +	}
> +
> +	node->iova = iova;
> +	node->perm = perm;
> +
> +	rte_rwlock_write_lock(&vq->iotlb_lock);
> +
> +	TAILQ_INSERT_TAIL(&vq->iotlb_pending_list, node, next);
> +
> +	rte_rwlock_write_unlock(&vq->iotlb_lock);
> +}
> +
> +static void vhost_user_iotlb_pending_remove(struct vhost_virtqueue *vq,
> +				uint64_t iova, uint64_t size, uint8_t perm)
> +{
> +	struct vhost_iotlb_entry *node, *temp_node;
> +
> +	/* .iotlb_lock already locked by the caller */
> +	TAILQ_FOREACH_SAFE(node, &vq->iotlb_pending_list, next, temp_node) {
> +		if (node->iova < iova)
> +			continue;
> +		if (node->iova >= iova + size)
> +			continue;
> +		if ((node->perm & perm) != node->perm)
> +			continue;
> +		TAILQ_REMOVE(&vq->iotlb_pending_list, node, next);
> +		rte_mempool_put(vq->iotlb_pool, node);
> +	}
> +}
>  
>  static void vhost_user_iotlb_cache_remove_all(struct vhost_virtqueue *vq)
>  {
> @@ -106,7 +185,10 @@ void vhost_user_iotlb_cache_insert(struct vhost_virtqueue *vq, uint64_t iova,
>  	TAILQ_INSERT_TAIL(&vq->iotlb_list, new_node, next);
>  
>  unlock:
> +	vhost_user_iotlb_pending_remove(vq, iova, size, perm);
> +
>  	rte_rwlock_write_unlock(&vq->iotlb_lock);
> +

This empty line should be removed.

Best regards,
Tiwei Bie

>  }
>  
>  void vhost_user_iotlb_cache_remove(struct vhost_virtqueue *vq,