[dpdk-dev] [PATCH v2] eal: add counter size for efd clean

[Tan, Jianfeng]

On 8/13/2017 8:03 AM, Jingjing Wu wrote:
> For virtual device, the rte_intr_handle struct is
> initialized by the virtual device driver, including
> the event fd assignment. If the event fd need to be
> read for clean, an argument is required for the proper
> event fd read.
>
> This patch adds efd_counter_size in rte_intr_handle
> struct to tell the rx interrupt process know the read
> size.

remove "know".

>
> Signed-off-by: Jingjing Wu <jingjing.wu at intel.com>

Besides, looks good to me.

Reviewed-by: Jianfeng Tan <jianfeng.tan at intel.com>

Thanks,
Jianfeng

> ---
>
> v2 change:
>   - fix typo and reword commit log
>
>   drivers/net/virtio/virtio_user/virtio_user_dev.c      |  2 ++
>   lib/librte_eal/linuxapp/eal/eal_interrupts.c          | 19 ++++++++++++-------
>   .../linuxapp/eal/include/exec-env/rte_interrupts.h    |  1 +
>   3 files changed, 15 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index 7941271..906d7a2 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -270,6 +270,8 @@ virtio_user_fill_intr_handle(struct virtio_user_dev *dev)
>   	eth_dev->intr_handle->nb_efd = dev->max_queue_pairs;
>   	eth_dev->intr_handle->max_intr = dev->max_queue_pairs + 1;
>   	eth_dev->intr_handle->type = RTE_INTR_HANDLE_VDEV;
> +	/* For virtio vdev, no need to read counter for clean */
> +	eth_dev->intr_handle->efd_counter_size = 0;
>   	if (dev->vhostfd >= 0)
>   		eth_dev->intr_handle->fd = dev->vhostfd;
>   
> diff --git a/lib/librte_eal/linuxapp/eal/eal_interrupts.c b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> index 3e9ac41..7de39c3 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
> @@ -914,7 +914,7 @@ static void
>   eal_intr_proc_rxtx_intr(int fd, const struct rte_intr_handle *intr_handle)
>   {
>   	union rte_intr_read_buffer buf;
> -	int bytes_read = 1;
> +	int bytes_read = 0;
>   	int nbytes;
>   
>   	switch (intr_handle->type) {
> @@ -930,11 +930,9 @@ eal_intr_proc_rxtx_intr(int fd, const struct rte_intr_handle *intr_handle)
>   		break;
>   #endif
>   	case RTE_INTR_HANDLE_VDEV:
> -		/* for vdev, fd points to:
> -		 * a. eventfd which does not need to read out;
> -		 * b. datapath fd which needs PMD to read out.
> -		 */
> -		return;
> +		bytes_read = intr_handle->efd_counter_size;
> +		/* For vdev, number of bytes to read is set by driver */
> +		break;
>   	case RTE_INTR_HANDLE_EXT:
>   		return;
>   	default:
> @@ -947,6 +945,8 @@ eal_intr_proc_rxtx_intr(int fd, const struct rte_intr_handle *intr_handle)
>   	 * read out to clear the ready-to-be-read flag
>   	 * for epoll_wait.
>   	 */
> +	if (bytes_read == 0)
> +		return;
>   	do {
>   		nbytes = read(fd, &buf, bytes_read);
>   		if (nbytes < 0) {
> @@ -1206,7 +1206,12 @@ rte_intr_efd_enable(struct rte_intr_handle *intr_handle, uint32_t nb_efd)
>   		intr_handle->nb_efd   = n;
>   		intr_handle->max_intr = NB_OTHER_INTR + n;
>   	} else if (intr_handle->type == RTE_INTR_HANDLE_VDEV) {
> -		/* do nothing, and let vdev driver to initialize this struct */
> +		/* only check, initialization would be done in vdev driver.*/
> +		if (intr_handle->efd_counter_size >
> +		    sizeof(union rte_intr_read_buffer)) {
> +			RTE_LOG(ERR, EAL, "the efd_counter_size is oversized");
> +			return -EINVAL;
> +		}
>   	} else {
>   		intr_handle->efds[0]  = intr_handle->fd;
>   		intr_handle->nb_efd   = RTE_MIN(nb_efd, 1U);
> diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
> index 6daffeb..fd4ea6c 100644
> --- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
> +++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
> @@ -93,6 +93,7 @@ struct rte_intr_handle {
>   	enum rte_intr_handle_type type;  /**< handle type */
>   	uint32_t max_intr;             /**< max interrupt requested */
>   	uint32_t nb_efd;               /**< number of available efd(event fd) */
> +	uint8_t efd_counter_size;      /**< size of efd counter, used for vdev */
>   	int efds[RTE_MAX_RXTX_INTR_VEC_ID];  /**< intr vectors/efds mapping */
>   	struct rte_epoll_event elist[RTE_MAX_RXTX_INTR_VEC_ID];
>   				       /**< intr vector epoll event */