diff mbox series

[RFC,1/2] vhost: support clear in-flight packets for async dequeue

Message ID 20220117132847.884998-2-yuanx.wang@intel.com (mailing list archive)
State Superseded, archived
Delegated to: Maxime Coquelin
Headers
Series support to clear in-flight packets for async |

Checks

Context Check Description
ci/checkpatch success coding style OK

Commit Message

Wang, YuanX Jan. 17, 2022, 1:28 p.m. UTC 
  rte_vhost_clear_queue_thread_unsafe() supports to clear
in-flight packets for async enqueue only. But after
supporting async dequeue, this API should support async dequeue too.

This patch also adds the thread-safe version of this API,
the difference between the two API is that thread safety uses lock.

These APIs maybe used to clean up packets in the async channel
to prevent packet loss when the device state changes or
when the device is destroyed.

Signed-off-by: Yuan Wang <yuanx.wang@intel.com>
---
 doc/guides/prog_guide/vhost_lib.rst    |  7 ++-
 doc/guides/rel_notes/release_22_03.rst |  5 ++
 lib/vhost/rte_vhost_async.h            | 26 ++++++++++
 lib/vhost/version.map                  |  1 +
 lib/vhost/virtio_net.c                 | 71 +++++++++++++++++++++++++-
 5 files changed, 107 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
index bdce7cbf02..7cea2490e5 100644
--- a/doc/guides/prog_guide/vhost_lib.rst
+++ b/doc/guides/prog_guide/vhost_lib.rst
@@ -269,7 +269,12 @@  The following is an overview of some key Vhost API functions:
 
 * ``rte_vhost_clear_queue_thread_unsafe(vid, queue_id, **pkts, count, dma_id, dma_vchan)``
 
-  Clear inflight packets which are submitted to DMA engine in vhost async data
+  Clear in-flight packets which are submitted to async channel in vhost
+  async data path without performing any locking. Completed packets are
+  returned to applications through ``pkts``.
+
+* ``rte_vhost_clear_queue(vid, queue_id, **pkts, count, dma_id, dma_vchan)``
+  Clear in-flight packets which are submitted to async channel in vhost async data
   path. Completed packets are returned to applications through ``pkts``.
 
 Vhost-user Implementations
diff --git a/doc/guides/rel_notes/release_22_03.rst b/doc/guides/rel_notes/release_22_03.rst
index 6d99d1eaa9..e774919fc9 100644
--- a/doc/guides/rel_notes/release_22_03.rst
+++ b/doc/guides/rel_notes/release_22_03.rst
@@ -55,6 +55,11 @@  New Features
      Also, make sure to start the actual text at the margin.
      =======================================================
 
+* **Added thread-safe version of inflight packet clear API in vhost library.**
+
+  Added an API which can clear the inflight packets submitted to
+  the async channel in a thread-safe manner in the vhost async data path.
+
 
 Removed Items
 -------------
diff --git a/lib/vhost/rte_vhost_async.h b/lib/vhost/rte_vhost_async.h
index b1249382cd..ed9389560b 100644
--- a/lib/vhost/rte_vhost_async.h
+++ b/lib/vhost/rte_vhost_async.h
@@ -186,6 +186,32 @@  __rte_experimental
 uint16_t rte_vhost_clear_queue_thread_unsafe(int vid, uint16_t queue_id,
 		struct rte_mbuf **pkts, uint16_t count, int16_t dma_id,
 		uint16_t vchan);
+
+/**
+ * This function checks async completion status and clear packets for
+ * a specific vhost device queue. Packets which are inflight will be
+ * returned in an array.
+ *
+ * @param vid
+ *  ID of vhost device to clear data
+ * @param queue_id
+ *  Queue id to clear data
+ * @param pkts
+ *  Blank array to get return packet pointer
+ * @param count
+ *  Size of the packet array
+ * @param dma_id
+ *  the identifier of the DMA device
+ * @param vchan
+ *  the identifier of virtual DMA channel
+ * @return
+ *  Number of packets returned
+ */
+__rte_experimental
+uint16_t rte_vhost_clear_queue(int vid, uint16_t queue_id,
+		struct rte_mbuf **pkts,	uint16_t count,	int16_t dma_id,
+		uint16_t vchan);
+
 /**
  * The DMA vChannels used in asynchronous data path must be configured
  * first. So this function needs to be called before enabling DMA
diff --git a/lib/vhost/version.map b/lib/vhost/version.map
index 816a6dc942..16f7d57380 100644
--- a/lib/vhost/version.map
+++ b/lib/vhost/version.map
@@ -88,6 +88,7 @@  EXPERIMENTAL {
 	# added in 22.03
 	rte_vhost_async_dma_configure;
 	rte_vhost_async_try_dequeue_burst;
+	rte_vhost_clear_queue;
 };
 
 INTERNAL {
diff --git a/lib/vhost/virtio_net.c b/lib/vhost/virtio_net.c
index 148709f2c5..510cd6ca8a 100644
--- a/lib/vhost/virtio_net.c
+++ b/lib/vhost/virtio_net.c
@@ -26,6 +26,11 @@ 
 
 #define MAX_BATCH_LEN 256
 
+static __rte_always_inline uint16_t
+async_poll_dequeue_completed_split(struct virtio_net *dev, uint16_t queue_id,
+		struct rte_mbuf **pkts, uint16_t count, uint16_t dma_id, uint16_t dma_vchan,
+		bool legacy_ol_flags);
+
 /* DMA device copy operation tracking array. */
 struct async_dma_info dma_copy_track[RTE_DMADEV_DEFAULT_MAX];
 
@@ -2042,7 +2047,49 @@  rte_vhost_clear_queue_thread_unsafe(int vid, uint16_t queue_id,
 		return 0;
 
 	VHOST_LOG_DATA(DEBUG, "(%d) %s\n", dev->vid, __func__);
-	if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->nr_vring))) {
+	if (unlikely(queue_id >= dev->nr_vring)) {
+		VHOST_LOG_DATA(ERR, "(%d) %s: invalid virtqueue idx %d.\n",
+				dev->vid, __func__, queue_id);
+		return 0;
+	}
+
+	vq = dev->virtqueue[queue_id];
+
+	if (unlikely(!vq->async)) {
+		VHOST_LOG_DATA(ERR, "(%d) %s: async not registered for queue id %d.\n",
+			dev->vid, __func__, queue_id);
+		return 0;
+	}
+
+	if (queue_id % 2 == 0)
+		n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id,
+					pkts, count, dma_id, vchan);
+	else {
+		if (unlikely(vq_is_packed(dev)))
+			VHOST_LOG_DATA(ERR,
+					"(%d) %s: async dequeue does not support packed ring.\n",
+					dev->vid, __func__);
+		else
+			n_pkts_cpl = async_poll_dequeue_completed_split(dev, queue_id, pkts, count,
+					dma_id, vchan, dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS);
+	}
+
+	return n_pkts_cpl;
+}
+
+uint16_t
+rte_vhost_clear_queue(int vid, uint16_t queue_id, struct rte_mbuf **pkts,
+		uint16_t count,	int16_t dma_id,	uint16_t vchan)
+{
+	struct virtio_net *dev = get_device(vid);
+	struct vhost_virtqueue *vq;
+	uint16_t n_pkts_cpl = 0;
+
+	if (!dev)
+		return 0;
+
+	VHOST_LOG_DATA(DEBUG, "(%d) %s\n", dev->vid, __func__);
+	if (unlikely(queue_id >= dev->nr_vring)) {
 		VHOST_LOG_DATA(ERR, "(%d) %s: invalid virtqueue idx %d.\n",
 			dev->vid, __func__, queue_id);
 		return 0;
@@ -2056,7 +2103,27 @@  rte_vhost_clear_queue_thread_unsafe(int vid, uint16_t queue_id,
 		return 0;
 	}
 
-	n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id, pkts, count, dma_id, vchan);
+	if (!rte_spinlock_trylock(&vq->access_lock)) {
+		VHOST_LOG_DATA(ERR,
+			"(%d) %s: failed to clear async queue id %d, virtqueue busy.\n",
+			dev->vid, __func__, queue_id);
+		return 0;
+	}
+
+	if (queue_id % 2 == 0)
+		n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id,
+					pkts, count, dma_id, vchan);
+	else {
+		if (unlikely(vq_is_packed(dev)))
+			VHOST_LOG_DATA(ERR,
+				"(%d) %s: async dequeue does not support packed ring.\n",
+				dev->vid, __func__);
+		else
+			n_pkts_cpl = async_poll_dequeue_completed_split(dev, queue_id, pkts, count,
+					dma_id, vchan, dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS);
+	}
+
+	rte_spinlock_unlock(&vq->access_lock);
 
 	return n_pkts_cpl;
 }