[dpdk-dev] [PATCH 4/4] doc: update async vhost register/unregister

Jiayu Hu jiayu.hu at intel.com
Wed Mar 17 13:56:13 CET 2021


Signed-off-by: Jiayu Hu <jiayu.hu at intel.com>
---
 doc/guides/prog_guide/vhost_lib.rst | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
index dc29229..333bd0a 100644
--- a/doc/guides/prog_guide/vhost_lib.rst
+++ b/doc/guides/prog_guide/vhost_lib.rst
@@ -208,9 +208,9 @@ The following is an overview of some key Vhost API functions:
 
 * ``rte_vhost_async_channel_register(vid, queue_id, features, ops)``
 
-  Register a vhost queue with async copy device channel.
-  Following device ``features`` must be specified together with the
-  registration:
+  Register a vhost queue with async copy device channel after vring
+  is enabled. Following device ``features`` must be specified together
+  with the registration:
 
   * ``async_inorder``
 
@@ -244,6 +244,13 @@ The following is an overview of some key Vhost API functions:
 * ``rte_vhost_async_channel_unregister(vid, queue_id)``
 
   Unregister the async copy device channel from a vhost queue.
+  Unregistration will fail, if the vhost queue has in-flight
+  packets that are not completed.
+
+  To guarantee correct behaviors, users must unregister async
+  copy devices for all vhost queues, when virtio device is paused
+  or shut down. Note that this API tries to acquire the spinlock
+  of vhost queue, so users need stop polling thread before unregister.
 
 * ``rte_vhost_submit_enqueue_burst(vid, queue_id, pkts, count, comp_pkts, comp_count)``
 
-- 
2.7.4



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