[v7,1/2] examples/vhost: add ioat ring space count and check

  Add ioat ring space count and check, if ioat ring space is not enough
for the next async vhost packet enqueue, then just return to prevent
enqueue failure. Add rte_ioat_completed_ops() fail handler.

Signed-off-by: Cheng Jiang <Cheng1.jiang@intel.com>
---
 examples/vhost/ioat.c | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)
  

Reviewed-by: Jiayu Hu <jiayu.hu@intel.com>

> -----Original Message-----
> From: Jiang, Cheng1 <cheng1.jiang@intel.com>
> Sent: Tuesday, January 5, 2021 10:15 AM
> To: maxime.coquelin@redhat.com; Xia, Chenbo <chenbo.xia@intel.com>
> Cc: dev@dpdk.org; Hu, Jiayu <jiayu.hu@intel.com>; Yang, YvonneX
> <yvonnex.yang@intel.com>; Wang, Yinan <yinan.wang@intel.com>; Jiang,
> Cheng1 <cheng1.jiang@intel.com>
> Subject: [PATCH v7 1/2] examples/vhost: add ioat ring space count and check
> 
> Add ioat ring space count and check, if ioat ring space is not enough
> for the next async vhost packet enqueue, then just return to prevent
> enqueue failure. Add rte_ioat_completed_ops() fail handler.
> 
> Signed-off-by: Cheng Jiang <Cheng1.jiang@intel.com>
> ---
>  examples/vhost/ioat.c | 24 +++++++++++++-----------
>  1 file changed, 13 insertions(+), 11 deletions(-)
> 
> diff --git a/examples/vhost/ioat.c b/examples/vhost/ioat.c
> index 71d8a1f1f5..dbad28d43e 100644
> --- a/examples/vhost/ioat.c
> +++ b/examples/vhost/ioat.c
> @@ -17,6 +17,7 @@ struct packet_tracker {
>  	unsigned short next_read;
>  	unsigned short next_write;
>  	unsigned short last_remain;
> +	unsigned short ioat_space;
>  };
> 
>  struct packet_tracker cb_tracker[MAX_VHOST_DEVICE];
> @@ -113,7 +114,7 @@ open_ioat(const char *value)
>  			goto out;
>  		}
>  		rte_rawdev_start(dev_id);
> -
> +		cb_tracker[dev_id].ioat_space = IOAT_RING_SIZE;
>  		dma_info->nr++;
>  		i++;
>  	}
> @@ -140,13 +141,9 @@ ioat_transfer_data_cb(int vid, uint16_t queue_id,
>  			src = descs[i_desc].src;
>  			dst = descs[i_desc].dst;
>  			i_seg = 0;
> +			if (cb_tracker[dev_id].ioat_space < src->nr_segs)
> +				break;
>  			while (i_seg < src->nr_segs) {
> -				/*
> -				 * TODO: Assuming that the ring space of the
> -				 * IOAT device is large enough, so there is no
> -				 * error here, and the actual error handling
> -				 * will be added later.
> -				 */
>  				rte_ioat_enqueue_copy(dev_id,
>  					(uintptr_t)(src->iov[i_seg].iov_base)
>  						+ src->offset,
> @@ -158,7 +155,8 @@ ioat_transfer_data_cb(int vid, uint16_t queue_id,
>  				i_seg++;
>  			}
>  			write &= mask;
> -			cb_tracker[dev_id].size_track[write] = i_seg;
> +			cb_tracker[dev_id].size_track[write] = src->nr_segs;
> +			cb_tracker[dev_id].ioat_space -= src->nr_segs;
>  			write++;
>  		}
>  	} else {
> @@ -178,17 +176,21 @@ ioat_check_completed_copies_cb(int vid, uint16_t
> queue_id,
>  {
>  	if (!opaque_data) {
>  		uintptr_t dump[255];
> -		unsigned short n_seg;
> +		int n_seg;
>  		unsigned short read, write;
>  		unsigned short nb_packet = 0;
>  		unsigned short mask = MAX_ENQUEUED_SIZE - 1;
>  		unsigned short i;
> +
>  		int dev_id = dma_bind[vid].dmas[queue_id * 2
>  				+ VIRTIO_RXQ].dev_id;
>  		n_seg = rte_ioat_completed_ops(dev_id, 255, dump, dump);
> -		n_seg += cb_tracker[dev_id].last_remain;
> -		if (!n_seg)
> +		if (n_seg <= 0)
>  			return 0;
> +
> +		cb_tracker[dev_id].ioat_space += n_seg;
> +		n_seg += cb_tracker[dev_id].last_remain;
> +
>  		read = cb_tracker[dev_id].next_read;
>  		write = cb_tracker[dev_id].next_write;
>  		for (i = 0; i < max_packets; i++) {
> --
> 2.29.2