Hi Jiayu,

-----Original Message-----
From: Hu, Jiayu <redacted>
Sent: Tuesday, January 5, 2021 9:20 AM
To: Jiang, Cheng1 <redacted>; maxime.coquelin@redhat.com;
Xia, Chenbo [off-list ref]
Cc: dev@dpdk.org; Yang, YvonneX <redacted>; Wang, Yinan
[off-list ref]
Subject: RE: [PATCH v6 1/2] examples/vhost: add ioat ring space count and
check

Hi Cheng,

quoted

-----Original Message-----
From: Jiang, Cheng1 <redacted>
Sent: Monday, January 4, 2021 12:58 PM
To: maxime.coquelin@redhat.com; Xia, Chenbo <redacted>
Cc: dev@dpdk.org; Hu, Jiayu <redacted>; Yang, YvonneX
[off-list ref]; Wang, Yinan [off-list ref]; Jiang,
Cheng1 [off-list ref]
Subject: [PATCH v6 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 <redacted>
---
 examples/vhost/ioat.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/examples/vhost/ioat.c b/examples/vhost/ioat.c index

71d8a1f1f5..679d1e2f58 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

quoted

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)  return 0;
+
+cb_tracker[dev_id].ioat_space += n_seg; n_seg +=
+cb_tracker[dev_id].last_remain;

When error happens in rte_ioat_completed_ops(), where n_seg is -1, the
value of "!n_seg" is false (0) and it can still pass the check of "if".

You are right, I think I just missed that
I will fix it in the next version, thanks a lot.

Cheng

Thanks,
Jiayu

quoted

+
 read = cb_tracker[dev_id].next_read;
 write = cb_tracker[dev_id].next_write;  for (i = 0; i < max_packets;
i++) {
--
2.29.2