diff mbox series

[RFC,v2,1/2] vhost: support clear in-flight packets for async dequeue

Message ID 20220311173414.93216-2-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State Superseded, archived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 March 11, 2022, 5:34 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 |  4 ++
 lib/vhost/rte_vhost_async.h            | 25 ++++++++
 lib/vhost/version.map                  |  1 +
 lib/vhost/virtio_net.c                 | 79 +++++++++++++++++++++++++-
 5 files changed, 113 insertions(+), 3 deletions(-)

Comments

Sunil Pai G March 28, 2022, 6:08 a.m. UTC | #1 
Hi Yuan,

Thanks for the patch, comment inline.

> +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_id) {
> +	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, "(%s) %s\n", dev->ifname, __func__);
> +	if (unlikely(queue_id >= dev->nr_vring)) {
> +		VHOST_LOG_DATA(ERR, "(%s) %s: invalid virtqueue idx %d.\n",
> +			dev->ifname, __func__, queue_id);
> +		return 0;
> +	}
> +
> +	vq = dev->virtqueue[queue_id];
> +

I think the following checks must be protected by spinlock.
Similar to : https://patches.dpdk.org/project/dpdk/patch/20220328020754.1155063-1-jiayu.hu@intel.com/ 

> +	if (unlikely(!vq->async)) {
> +		VHOST_LOG_DATA(ERR, "(%s) %s: async not registered for queue
> id %d.\n",
> +			dev->ifname, __func__, queue_id);
> +		return 0;
> +	}
> +
> +	if (unlikely(!dma_copy_track[dma_id].vchans ||
> +
> 	!dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr)) {
> +		VHOST_LOG_DATA(ERR, "(%s) %s: invalid channel %d:%u.\n", dev-
> >ifname, __func__,
> +				dma_id, vchan_id);
> +		return 0;
> +	}
> +
> +	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;
> +	}
> +

<snipped>

Thanks and regards,
Sunil
Wang, YuanX March 29, 2022, 9:51 a.m. UTC | #2 
Hi Sunil,

> -----Original Message-----
> From: Pai G, Sunil <sunil.pai.g@intel.com>
> Sent: Monday, March 28, 2022 2:08 PM
> To: Wang, YuanX <yuanx.wang@intel.com>; maxime.coquelin@redhat.com;
> Xia, Chenbo <chenbo.xia@intel.com>
> Cc: dev@dpdk.org; Hu, Jiayu <jiayu.hu@intel.com>; Ding, Xuan
> <xuan.ding@intel.com>; Yang, YvonneX <yvonnex.yang@intel.com>
> Subject: RE: [RFC v2 1/2] vhost: support clear in-flight packets for async
> dequeue
> 
> Hi Yuan,
> 
> Thanks for the patch, comment inline.
> 
> > +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_id) {
> > +	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, "(%s) %s\n", dev->ifname, __func__);
> > +	if (unlikely(queue_id >= dev->nr_vring)) {
> > +		VHOST_LOG_DATA(ERR, "(%s) %s: invalid virtqueue
> idx %d.\n",
> > +			dev->ifname, __func__, queue_id);
> > +		return 0;
> > +	}
> > +
> > +	vq = dev->virtqueue[queue_id];
> > +
> 
> I think the following checks must be protected by spinlock.
> Similar to :
> https://patches.dpdk.org/project/dpdk/patch/20220328020754.1155063-1-
> jiayu.hu@intel.com/

Thanks for the comment.
Will fix it in next version.

Thanks,
Yuan

> 
> > +	if (unlikely(!vq->async)) {
> > +		VHOST_LOG_DATA(ERR, "(%s) %s: async not registered for
> queue
> > id %d.\n",
> > +			dev->ifname, __func__, queue_id);
> > +		return 0;
> > +	}
> > +
> > +	if (unlikely(!dma_copy_track[dma_id].vchans ||
> > +
> > 	!dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr))
> {
> > +		VHOST_LOG_DATA(ERR, "(%s) %s: invalid channel %d:%u.\n",
> dev-
> > >ifname, __func__,
> > +				dma_id, vchan_id);
> > +		return 0;
> > +	}
> > +
> > +	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;
> > +	}
> > +
> 
> <snipped>
> 
> Thanks and regards,
> Sunil
diff mbox series

Patch

diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
index 886f8f5e72..bbb7333d03 100644
--- a/doc/guides/prog_guide/vhost_lib.rst
+++ b/doc/guides/prog_guide/vhost_lib.rst
@@ -273,7 +273,12 @@  The following is an overview of some key Vhost API functions:
 
 * ``rte_vhost_clear_queue_thread_unsafe(vid, queue_id, **pkts, count, dma_id, vchan_id)``
 
-  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, vchan_id)``
+  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 60e5b4f9aa..ab754056b9 100644
--- a/doc/guides/rel_notes/release_22_03.rst
+++ b/doc/guides/rel_notes/release_22_03.rst
@@ -232,6 +232,10 @@  New Features
   * Crypto producer mode helps to measure performance of OP_NEW and OP_FORWARD
     modes of event crypto adapter.
 
+* **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 b6ab0b06a2..eb1ddb2ec1 100644
--- a/lib/vhost/rte_vhost_async.h
+++ b/lib/vhost/rte_vhost_async.h
@@ -166,6 +166,31 @@  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_id);
 
+/**
+ * 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_id
+ *  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_id);
+
 /**
  * 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 968d6d4290..11c5fa635d 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 3816caca79..ca96632ee5 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 vchan_id, bool legacy_ol_flags);
+
 /* DMA device copy operation tracking array. */
 struct async_dma_info dma_copy_track[RTE_DMADEV_DEFAULT_MAX];
 
@@ -2083,7 +2088,7 @@  rte_vhost_clear_queue_thread_unsafe(int vid, uint16_t queue_id,
 		return 0;
 
 	VHOST_LOG_DATA(DEBUG, "(%s) %s\n", dev->ifname, __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, "(%s) %s: invalid virtqueue idx %d.\n",
 			dev->ifname, __func__, queue_id);
 		return 0;
@@ -2104,11 +2109,81 @@  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_id);
+	if (queue_id % 2 == 0)
+		n_pkts_cpl = vhost_poll_enqueue_completed(dev, queue_id,
+					pkts, count, dma_id, vchan_id);
+	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_id, 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_id)
+{
+	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, "(%s) %s\n", dev->ifname, __func__);
+	if (unlikely(queue_id >= dev->nr_vring)) {
+		VHOST_LOG_DATA(ERR, "(%s) %s: invalid virtqueue idx %d.\n",
+			dev->ifname, __func__, queue_id);
+		return 0;
+	}
+
+	vq = dev->virtqueue[queue_id];
+
+	if (unlikely(!vq->async)) {
+		VHOST_LOG_DATA(ERR, "(%s) %s: async not registered for queue id %d.\n",
+			dev->ifname, __func__, queue_id);
+		return 0;
+	}
+
+	if (unlikely(!dma_copy_track[dma_id].vchans ||
+				!dma_copy_track[dma_id].vchans[vchan_id].pkts_cmpl_flag_addr)) {
+		VHOST_LOG_DATA(ERR, "(%s) %s: invalid channel %d:%u.\n", dev->ifname, __func__,
+				dma_id, vchan_id);
+		return 0;
+	}
+
+	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_id);
+	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_id, dev->flags & VIRTIO_DEV_LEGACY_OL_FLAGS);
+	}
+
+	rte_spinlock_unlock(&vq->access_lock);
 
 	return n_pkts_cpl;
 }
 
+
 static __rte_always_inline uint32_t
 virtio_dev_rx_async_submit(struct virtio_net *dev, uint16_t queue_id,
 	struct rte_mbuf **pkts, uint32_t count, int16_t dma_id, uint16_t vchan_id)