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

[Maxime Coquelin]

On 09/05/2017 09:11 AM, Tiwei Bie wrote:
> 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 at 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.

Fixed.

>> +	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.

Fixed.
> 
>> +		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.

Yes, this part disappears in next version, as I squashed patch 21 in
patches 7 & 8.

Thanks,
Maxime
> Best regards,
> Tiwei Bie
> 
>>   }
>>   
>>   void vhost_user_iotlb_cache_remove(struct vhost_virtqueue *vq,