On 4/8/22 12:22, xuan.d...@intel.com wrote:
From: Xuan Ding <xuan.d...@intel.com>
In async data path, when vring state changes or device is destroyed,
it is necessary to know the number of inflight packets in DMA engine.
This patch provides a thread unsafe API to return the number of
inflight packets for a vhost queue without using any lock.
Signed-off-by: Xuan Ding <xuan.d...@intel.com>
---
doc/guides/prog_guide/vhost_lib.rst | 6 ++++++
doc/guides/rel_notes/release_22_07.rst | 4 ++++
lib/vhost/rte_vhost_async.h | 17 +++++++++++++++++
lib/vhost/version.map | 4 ++++
lib/vhost/vhost.c | 26 ++++++++++++++++++++++++++
5 files changed, 57 insertions(+)
diff --git a/doc/guides/prog_guide/vhost_lib.rst
b/doc/guides/prog_guide/vhost_lib.rst
index 886f8f5e72..f287b76ebf 100644
--- a/doc/guides/prog_guide/vhost_lib.rst
+++ b/doc/guides/prog_guide/vhost_lib.rst
@@ -271,6 +271,12 @@ The following is an overview of some key Vhost API
functions:
This function returns the amount of in-flight packets for the vhost
queue using async acceleration.
+ * ``rte_vhost_async_get_inflight_thread_unsafe(vid, queue_id)``
+
+ Get the number of inflight packets for a vhost queue without performing
+ any locking. It should only be used within the vhost ops, which already
+ holds the lock.
+
* ``rte_vhost_clear_queue_thread_unsafe(vid, queue_id, **pkts, count, dma_id,
vchan_id)``
Clear inflight packets which are submitted to DMA engine in vhost async data
diff --git a/doc/guides/rel_notes/release_22_07.rst
b/doc/guides/rel_notes/release_22_07.rst
index 42a5f2d990..a0c5d9459b 100644
--- a/doc/guides/rel_notes/release_22_07.rst
+++ b/doc/guides/rel_notes/release_22_07.rst
@@ -55,6 +55,10 @@ New Features
Also, make sure to start the actual text at the margin.
=======================================================
+* **Added vhost API to get the number of inflight packets.**
+
+ Added an API which can get the number of inflight packets in
+ vhost async data path without using lock.
Removed Items
-------------
diff --git a/lib/vhost/rte_vhost_async.h b/lib/vhost/rte_vhost_async.h
index f1293c6a9d..70234debf9 100644
--- a/lib/vhost/rte_vhost_async.h
+++ b/lib/vhost/rte_vhost_async.h
@@ -139,6 +139,23 @@ uint16_t rte_vhost_poll_enqueue_completed(int vid,
uint16_t queue_id,
__rte_experimental
int rte_vhost_async_get_inflight(int vid, uint16_t queue_id);
+/**
+ * This function is lock-free version to return the amount of in-flight
+ * packets for the vhost queue which uses async channel acceleration.
+ *
+ * @note This function does not perform any locking, it should only be
+ * used within the vhost ops, which already holds the lock.
+ *
+ * @param vid
+ * id of vhost device to enqueue data
+ * @param queue_id
+ * queue id to enqueue data
+ * @return
+ * the amount of in-flight packets on success; -1 on failure
+ */
+__rte_experimental
+int rte_vhost_async_get_inflight_thread_unsafe(int vid, uint16_t queue_id);
+
/**
* This function checks async completion status and clear packets for
* a specific vhost device queue. Packets which are inflight will be
diff --git a/lib/vhost/version.map b/lib/vhost/version.map
index 0a66c5840c..5841315386 100644
--- a/lib/vhost/version.map
+++ b/lib/vhost/version.map
@@ -87,6 +87,10 @@ EXPERIMENTAL {
# added in 22.03
rte_vhost_async_dma_configure;
+
+ # added in 22.07
+ rte_vhost_async_get_inflight_thread_unsafe;
+
};
INTERNAL {
diff --git a/lib/vhost/vhost.c b/lib/vhost/vhost.c
index 2f96a28dac..df0bb9d043 100644
--- a/lib/vhost/vhost.c
+++ b/lib/vhost/vhost.c
@@ -1907,6 +1907,32 @@ rte_vhost_async_get_inflight(int vid, uint16_t queue_id)
return ret;
}
+int
+rte_vhost_async_get_inflight_thread_unsafe(int vid, uint16_t queue_id)
+{
+ struct vhost_virtqueue *vq;
+ struct virtio_net *dev = get_device(vid);
+ int ret = -1;
+
+ if (dev == NULL)
+ return ret;
+
+ if (queue_id >= VHOST_MAX_VRING)
+ return ret;
+
+ vq = dev->virtqueue[queue_id];
+
+ if (vq == NULL)
+ return ret;
FYI, I'm going to post a patch that adds a call to
rte_spinlock_is_locked() to catch possible misuses of the API.
+ if (!vq->async)
+ return ret;
+
+ ret = vq->async->pkts_inflight_n;
+
+ return ret;
+}
+
int
rte_vhost_get_monitor_addr(int vid, uint16_t queue_id,
struct rte_vhost_power_monitor_cond *pmc)
Reviewed-by: Maxime Coquelin <maxime.coque...@redhat.com>
Thanks,
Maxime
