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From: "Xia, Chenbo" <chenbo.xia@intel.com>
To: Maxime Coquelin <maxime.coquelin@redhat.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"Stokes, Ian" <ian.stokes@intel.com>
Subject: Re: [dpdk-dev] [PATCH 4/4] vhost: remove dequeue zero-copy support
Date: Wed, 23 Sep 2020 05:44:14 +0000
Message-ID: <MN2PR11MB40630FB967AE506F39061F289C380@MN2PR11MB4063.namprd11.prod.outlook.com> (raw)
In-Reply-To: <20200915133558.210639-5-maxime.coquelin@redhat.com>

Hi Maxime,

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, September 15, 2020 9:36 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; Stokes, Ian
> <ian.stokes@intel.com>
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH 4/4] vhost: remove dequeue zero-copy support
> 
> Dequeue zero-copy removal was announced in DPDK v20.08.
> This feature brings constraints which makes the maintenance
> of the Vhost library difficult. Its limitations makes it also
> diffcult to use by the applications (Tx vring starvation).

s/diffcult/difficult

Besides, there's some zcopy-related struct and function in vhost.h.
Should clean them up too 😊.

And in func 'free_mem_region', you can delete 'struct vhost_virtqueue *vq;'
Because it's not in use now. 

Thanks!
Chenbo

> 
> Removing it makes it easier to add new features, and also remove
> some code in the hot path, which should bring a performance
> improvement for the standard path.
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
>  doc/guides/prog_guide/vhost_lib.rst |  52 +----
>  lib/librte_vhost/rte_vhost.h        |   2 +-
>  lib/librte_vhost/socket.c           |  47 ----
>  lib/librte_vhost/vhost.c            |  14 --
>  lib/librte_vhost/vhost.h            |   7 -
>  lib/librte_vhost/vhost_user.c       |  79 +------
>  lib/librte_vhost/virtio_net.c       | 326 +++-------------------------
>  7 files changed, 33 insertions(+), 494 deletions(-)
> 
> diff --git a/doc/guides/prog_guide/vhost_lib.rst
> b/doc/guides/prog_guide/vhost_lib.rst
> index b892eec67a..ba4c62aeb8 100644
> --- a/doc/guides/prog_guide/vhost_lib.rst
> +++ b/doc/guides/prog_guide/vhost_lib.rst
> @@ -51,50 +51,6 @@ The following is an overview of some key Vhost API
> functions:
>      This reconnect option is enabled by default. However, it can be
> turned off
>      by setting this flag.
> 
> -  - ``RTE_VHOST_USER_DEQUEUE_ZERO_COPY``
> -
> -    Dequeue zero copy will be enabled when this flag is set. It is
> disabled by
> -    default.
> -
> -    There are some truths (including limitations) you might want to know
> while
> -    setting this flag:
> -
> -    * zero copy is not good for small packets (typically for packet size
> below
> -      512).
> -
> -    * zero copy is really good for VM2VM case. For iperf between two VMs,
> the
> -      boost could be above 70% (when TSO is enabled).
> -
> -    * For zero copy in VM2NIC case, guest Tx used vring may be starved if
> the
> -      PMD driver consume the mbuf but not release them timely.
> -
> -      For example, i40e driver has an optimization to maximum NIC
> pipeline which
> -      postpones returning transmitted mbuf until only tx_free_threshold
> free
> -      descs left. The virtio TX used ring will be starved if the formula
> -      (num_i40e_tx_desc - num_virtio_tx_desc > tx_free_threshold) is true,
> since
> -      i40e will not return back mbuf.
> -
> -      A performance tip for tuning zero copy in VM2NIC case is to adjust
> the
> -      frequency of mbuf free (i.e. adjust tx_free_threshold of i40e
> driver) to
> -      balance consumer and producer.
> -
> -    * Guest memory should be backended with huge pages to achieve better
> -      performance. Using 1G page size is the best.
> -
> -      When dequeue zero copy is enabled, the guest phys address and host
> phys
> -      address mapping has to be established. Using non-huge pages means
> far
> -      more page segments. To make it simple, DPDK vhost does a linear
> search
> -      of those segments, thus the fewer the segments, the quicker we will
> get
> -      the mapping. NOTE: we may speed it by using tree searching in
> future.
> -
> -    * zero copy can not work when using vfio-pci with iommu mode
> currently, this
> -      is because we don't setup iommu dma mapping for guest memory. If
> you have
> -      to use vfio-pci driver, please insert vfio-pci kernel module in
> noiommu
> -      mode.
> -
> -    * The consumer of zero copy mbufs should consume these mbufs as soon
> as
> -      possible, otherwise it may block the operations in vhost.
> -
>    - ``RTE_VHOST_USER_IOMMU_SUPPORT``
> 
>      IOMMU support will be enabled when this flag is set. It is disabled
> by
> @@ -362,16 +318,16 @@ Guest memory requirement
> 
>  * Memory pre-allocation
> 
> -  For non-zerocopy non-async data path, guest memory pre-allocation is
> not a
> +  For non-async data path, guest memory pre-allocation is not a
>    must. This can help save of memory. If users really want the guest
> memory
>    to be pre-allocated (e.g., for performance reason), we can add option
>    ``-mem-prealloc`` when starting QEMU. Or, we can lock all memory at
> vhost
>    side which will force memory to be allocated when mmap at vhost side;
>    option --mlockall in ovs-dpdk is an example in hand.
> 
> -  For async and zerocopy data path, we force the VM memory to be
> -  pre-allocated at vhost lib when mapping the guest memory; and also we
> need
> -  to lock the memory to prevent pages being swapped out to disk.
> +  For async data path, we force the VM memory to be pre-allocated at
> vhost
> +  lib when mapping the guest memory; and also we need to lock the memory
> to
> +  prevent pages being swapped out to disk.
> 
>  * Memory sharing
> 
> diff --git a/lib/librte_vhost/rte_vhost.h b/lib/librte_vhost/rte_vhost.h
> index a94c84134d..46019df6fe 100644
> --- a/lib/librte_vhost/rte_vhost.h
> +++ b/lib/librte_vhost/rte_vhost.h
> @@ -28,7 +28,7 @@ extern "C" {
> 
>  #define RTE_VHOST_USER_CLIENT		(1ULL << 0)
>  #define RTE_VHOST_USER_NO_RECONNECT	(1ULL << 1)
> -#define RTE_VHOST_USER_DEQUEUE_ZERO_COPY	(1ULL << 2)
> +#define RTE_VHOST_USER_RESERVED_1	(1ULL << 2)
>  #define RTE_VHOST_USER_IOMMU_SUPPORT	(1ULL << 3)
>  #define RTE_VHOST_USER_POSTCOPY_SUPPORT		(1ULL << 4)
>  /* support mbuf with external buffer attached */
> diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
> index 73e1dca95e..0169d36481 100644
> --- a/lib/librte_vhost/socket.c
> +++ b/lib/librte_vhost/socket.c
> @@ -37,7 +37,6 @@ struct vhost_user_socket {
>  	struct sockaddr_un un;
>  	bool is_server;
>  	bool reconnect;
> -	bool dequeue_zero_copy;
>  	bool iommu_support;
>  	bool use_builtin_virtio_net;
>  	bool extbuf;
> @@ -229,9 +228,6 @@ vhost_user_add_connection(int fd, struct
> vhost_user_socket *vsocket)
> 
>  	vhost_attach_vdpa_device(vid, vsocket->vdpa_dev);
> 
> -	if (vsocket->dequeue_zero_copy)
> -		vhost_enable_dequeue_zero_copy(vid);
> -
>  	if (vsocket->extbuf)
>  		vhost_enable_extbuf(vid);
> 
> @@ -878,18 +874,8 @@ rte_vhost_driver_register(const char *path, uint64_t
> flags)
>  		goto out_free;
>  	}
>  	vsocket->vdpa_dev = NULL;
> -	vsocket->dequeue_zero_copy = flags &
> RTE_VHOST_USER_DEQUEUE_ZERO_COPY;
>  	vsocket->extbuf = flags & RTE_VHOST_USER_EXTBUF_SUPPORT;
>  	vsocket->linearbuf = flags & RTE_VHOST_USER_LINEARBUF_SUPPORT;
> -
> -	if (vsocket->dequeue_zero_copy &&
> -	    (flags & RTE_VHOST_USER_IOMMU_SUPPORT)) {
> -		VHOST_LOG_CONFIG(ERR,
> -			"error: enabling dequeue zero copy and IOMMU features "
> -			"simultaneously is not supported\n");
> -		goto out_mutex;
> -	}
> -
>  	vsocket->async_copy = flags & RTE_VHOST_USER_ASYNC_COPY;
> 
>  	if (vsocket->async_copy &&
> @@ -918,39 +904,6 @@ rte_vhost_driver_register(const char *path, uint64_t
> flags)
>  	vsocket->features           = VIRTIO_NET_SUPPORTED_FEATURES;
>  	vsocket->protocol_features  = VHOST_USER_PROTOCOL_FEATURES;
> 
> -	/*
> -	 * Dequeue zero copy can't assure descriptors returned in order.
> -	 * Also, it requires that the guest memory is populated, which is
> -	 * not compatible with postcopy.
> -	 */
> -	if (vsocket->dequeue_zero_copy) {
> -		if (vsocket->extbuf) {
> -			VHOST_LOG_CONFIG(ERR,
> -			"error: zero copy is incompatible with external
> buffers\n");
> -			ret = -1;
> -			goto out_mutex;
> -		}
> -		if (vsocket->linearbuf) {
> -			VHOST_LOG_CONFIG(ERR,
> -			"error: zero copy is incompatible with linear
> buffers\n");
> -			ret = -1;
> -			goto out_mutex;
> -		}
> -		if ((flags & RTE_VHOST_USER_CLIENT) != 0) {
> -			VHOST_LOG_CONFIG(ERR,
> -			"error: zero copy is incompatible with vhost client
> mode\n");
> -			ret = -1;
> -			goto out_mutex;
> -		}
> -		vsocket->supported_features &= ~(1ULL << VIRTIO_F_IN_ORDER);
> -		vsocket->features &= ~(1ULL << VIRTIO_F_IN_ORDER);
> -
> -		VHOST_LOG_CONFIG(INFO,
> -			"Dequeue zero copy requested, disabling postcopy
> support\n");
> -		vsocket->protocol_features &=
> -			~(1ULL << VHOST_USER_PROTOCOL_F_PAGEFAULT);
> -	}
> -
>  	if (vsocket->async_copy) {
>  		vsocket->supported_features &= ~(1ULL << VHOST_F_LOG_ALL);
>  		vsocket->features &= ~(1ULL << VHOST_F_LOG_ALL);
> diff --git a/lib/librte_vhost/vhost.c b/lib/librte_vhost/vhost.c
> index 8f20a0818f..c7cd34e42b 100644
> --- a/lib/librte_vhost/vhost.c
> +++ b/lib/librte_vhost/vhost.c
> @@ -539,8 +539,6 @@ init_vring_queue(struct virtio_net *dev, uint32_t
> vring_idx)
>  	vhost_user_iotlb_init(dev, vring_idx);
>  	/* Backends are set to -1 indicating an inactive device. */
>  	vq->backend = -1;
> -
> -	TAILQ_INIT(&vq->zmbuf_list);
>  }
> 
>  static void
> @@ -704,18 +702,6 @@ vhost_set_ifname(int vid, const char *if_name,
> unsigned int if_len)
>  	dev->ifname[sizeof(dev->ifname) - 1] = '\0';
>  }
> 
> -void
> -vhost_enable_dequeue_zero_copy(int vid)
> -{
> -	struct virtio_net *dev = get_device(vid);
> -
> -	if (dev == NULL)
> -		return;
> -
> -	dev->dequeue_zero_copy = 1;
> -	VHOST_LOG_CONFIG(INFO, "dequeue zero copy is enabled\n");
> -}
> -
>  void
>  vhost_set_builtin_virtio_net(int vid, bool enable)
>  {
> diff --git a/lib/librte_vhost/vhost.h b/lib/librte_vhost/vhost.h
> index 632f66d532..321cf6e99c 100644
> --- a/lib/librte_vhost/vhost.h
> +++ b/lib/librte_vhost/vhost.h
> @@ -379,7 +379,6 @@ struct virtio_net {
>  	/* to tell if we need broadcast rarp packet */
>  	int16_t			broadcast_rarp;
>  	uint32_t		nr_vring;
> -	int			dequeue_zero_copy;
>  	int			async_copy;
>  	int			extbuf;
>  	int			linearbuf;
> @@ -897,10 +896,4 @@ mbuf_is_consumed(struct rte_mbuf *m)
>  	return true;
>  }
> 
> -static __rte_always_inline void
> -put_zmbuf(struct zcopy_mbuf *zmbuf)
> -{
> -	zmbuf->in_use = 0;
> -}
> -
>  #endif /* _VHOST_NET_CDEV_H_ */
> diff --git a/lib/librte_vhost/vhost_user.c b/lib/librte_vhost/vhost_user.c
> index c3c924faec..8af5ea0a98 100644
> --- a/lib/librte_vhost/vhost_user.c
> +++ b/lib/librte_vhost/vhost_user.c
> @@ -134,29 +134,6 @@ get_blk_size(int fd)
>  	return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize;
>  }
> 
> -/*
> - * Reclaim all the outstanding zmbufs for a virtqueue.
> - */
> -static void
> -drain_zmbuf_list(struct vhost_virtqueue *vq)
> -{
> -	struct zcopy_mbuf *zmbuf, *next;
> -
> -	for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
> -	     zmbuf != NULL; zmbuf = next) {
> -		next = TAILQ_NEXT(zmbuf, next);
> -
> -		while (!mbuf_is_consumed(zmbuf->mbuf))
> -			usleep(1000);
> -
> -		TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
> -		restore_mbuf(zmbuf->mbuf);
> -		rte_pktmbuf_free(zmbuf->mbuf);
> -		put_zmbuf(zmbuf);
> -		vq->nr_zmbuf -= 1;
> -	}
> -}
> -
>  static void
>  free_mem_region(struct virtio_net *dev)
>  {
> @@ -167,14 +144,6 @@ free_mem_region(struct virtio_net *dev)
>  	if (!dev || !dev->mem)
>  		return;
> 
> -	if (dev->dequeue_zero_copy) {
> -		for (i = 0; i < dev->nr_vring; i++) {
> -			vq = dev->virtqueue[i];
> -			if (vq)
> -				drain_zmbuf_list(vq);
> -		}
> -	}
> -
>  	for (i = 0; i < dev->mem->nregions; i++) {
>  		reg = &dev->mem->regions[i];
>  		if (reg->host_user_addr) {
> @@ -454,23 +423,6 @@ vhost_user_set_vring_num(struct virtio_net **pdev,
>  		return RTE_VHOST_MSG_RESULT_ERR;
>  	}
> 
> -	if (dev->dequeue_zero_copy) {
> -		vq->nr_zmbuf = 0;
> -		vq->last_zmbuf_idx = 0;
> -		vq->zmbuf_size = vq->size;
> -		if (vq->zmbufs)
> -			rte_free(vq->zmbufs);
> -		vq->zmbufs = rte_zmalloc(NULL, vq->zmbuf_size *
> -					 sizeof(struct zcopy_mbuf), 0);
> -		if (vq->zmbufs == NULL) {
> -			VHOST_LOG_CONFIG(WARNING,
> -				"failed to allocate mem for zero copy; "
> -				"zero copy is force disabled\n");
> -			dev->dequeue_zero_copy = 0;
> -		}
> -		TAILQ_INIT(&vq->zmbuf_list);
> -	}
> -
>  	if (vq_is_packed(dev)) {
>  		if (vq->shadow_used_packed)
>  			rte_free(vq->shadow_used_packed);
> @@ -524,7 +476,6 @@ numa_realloc(struct virtio_net *dev, int index)
>  	int oldnode, newnode;
>  	struct virtio_net *old_dev;
>  	struct vhost_virtqueue *old_vq, *vq;
> -	struct zcopy_mbuf *new_zmbuf;
>  	struct vring_used_elem *new_shadow_used_split;
>  	struct vring_used_elem_packed *new_shadow_used_packed;
>  	struct batch_copy_elem *new_batch_copy_elems;
> @@ -555,16 +506,6 @@ numa_realloc(struct virtio_net *dev, int index)
>  			return dev;
> 
>  		memcpy(vq, old_vq, sizeof(*vq));
> -		TAILQ_INIT(&vq->zmbuf_list);
> -
> -		if (dev->dequeue_zero_copy) {
> -			new_zmbuf = rte_malloc_socket(NULL, vq->zmbuf_size *
> -					sizeof(struct zcopy_mbuf), 0, newnode);
> -			if (new_zmbuf) {
> -				rte_free(vq->zmbufs);
> -				vq->zmbufs = new_zmbuf;
> -			}
> -		}
> 
>  		if (vq_is_packed(dev)) {
>  			new_shadow_used_packed = rte_malloc_socket(NULL,
> @@ -1179,8 +1120,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  			goto err_mmap;
>  		}
> 
> -		populate = (dev->dequeue_zero_copy || dev->async_copy) ?
> -			MAP_POPULATE : 0;
> +		populate = dev->async_copy ? MAP_POPULATE : 0;
>  		mmap_addr = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
>  				 MAP_SHARED | populate, fd, 0);
> 
> @@ -1195,7 +1135,7 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  		reg->host_user_addr = (uint64_t)(uintptr_t)mmap_addr +
>  				      mmap_offset;
> 
> -		if (dev->dequeue_zero_copy || dev->async_copy)
> +		if (dev->async_copy)
>  			if (add_guest_pages(dev, reg, alignment) < 0) {
>  				VHOST_LOG_CONFIG(ERR,
>  					"adding guest pages to region %u failed.\n",
> @@ -1933,15 +1873,6 @@ vhost_user_set_vring_kick(struct virtio_net **pdev,
> struct VhostUserMsg *msg,
>  	return RTE_VHOST_MSG_RESULT_OK;
>  }
> 
> -static void
> -free_zmbufs(struct vhost_virtqueue *vq)
> -{
> -	drain_zmbuf_list(vq);
> -
> -	rte_free(vq->zmbufs);
> -	vq->zmbufs = NULL;
> -}
> -
>  /*
>   * when virtio is stopped, qemu will send us the GET_VRING_BASE message.
>   */
> @@ -1996,8 +1927,6 @@ vhost_user_get_vring_base(struct virtio_net **pdev,
> 
>  	vq->signalled_used_valid = false;
> 
> -	if (dev->dequeue_zero_copy)
> -		free_zmbufs(vq);
>  	if (vq_is_packed(dev)) {
>  		rte_free(vq->shadow_used_packed);
>  		vq->shadow_used_packed = NULL;
> @@ -2051,10 +1980,6 @@ vhost_user_set_vring_enable(struct virtio_net
> **pdev,
>  		}
>  	}
> 
> -	/* On disable, rings have to be stopped being processed. */
> -	if (!enable && dev->dequeue_zero_copy)
> -		drain_zmbuf_list(dev->virtqueue[index]);
> -
>  	dev->virtqueue[index]->enabled = enable;
> 
>  	return RTE_VHOST_MSG_RESULT_OK;
> diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
> index bd9303c8a9..0a0bea1a5a 100644
> --- a/lib/librte_vhost/virtio_net.c
> +++ b/lib/librte_vhost/virtio_net.c
> @@ -1946,7 +1946,7 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  		  struct rte_mbuf *m, struct rte_mempool *mbuf_pool)
>  {
>  	uint32_t buf_avail, buf_offset;
> -	uint64_t buf_addr, buf_iova, buf_len;
> +	uint64_t buf_addr, buf_len;
>  	uint32_t mbuf_avail, mbuf_offset;
>  	uint32_t cpy_len;
>  	struct rte_mbuf *cur = m, *prev = m;
> @@ -1958,7 +1958,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	int error = 0;
> 
>  	buf_addr = buf_vec[vec_idx].buf_addr;
> -	buf_iova = buf_vec[vec_idx].buf_iova;
>  	buf_len = buf_vec[vec_idx].buf_len;
> 
>  	if (unlikely(buf_len < dev->vhost_hlen && nr_vec <= 1)) {
> @@ -1988,14 +1987,12 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  		buf_offset = dev->vhost_hlen - buf_len;
>  		vec_idx++;
>  		buf_addr = buf_vec[vec_idx].buf_addr;
> -		buf_iova = buf_vec[vec_idx].buf_iova;
>  		buf_len = buf_vec[vec_idx].buf_len;
>  		buf_avail  = buf_len - buf_offset;
>  	} else if (buf_len == dev->vhost_hlen) {
>  		if (unlikely(++vec_idx >= nr_vec))
>  			goto out;
>  		buf_addr = buf_vec[vec_idx].buf_addr;
> -		buf_iova = buf_vec[vec_idx].buf_iova;
>  		buf_len = buf_vec[vec_idx].buf_len;
> 
>  		buf_offset = 0;
> @@ -2012,48 +2009,23 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	mbuf_offset = 0;
>  	mbuf_avail  = m->buf_len - RTE_PKTMBUF_HEADROOM;
>  	while (1) {
> -		uint64_t hpa;
> -
>  		cpy_len = RTE_MIN(buf_avail, mbuf_avail);
> 
> -		/*
> -		 * A desc buf might across two host physical pages that are
> -		 * not continuous. In such case (gpa_to_hpa returns 0), data
> -		 * will be copied even though zero copy is enabled.
> -		 */
> -		if (unlikely(dev->dequeue_zero_copy && (hpa = gpa_to_hpa(dev,
> -					buf_iova + buf_offset, cpy_len)))) {
> -			cur->data_len = cpy_len;
> -			cur->data_off = 0;
> -			cur->buf_addr =
> -				(void *)(uintptr_t)(buf_addr + buf_offset);
> -			cur->buf_iova = hpa;
> -
> -			/*
> -			 * In zero copy mode, one mbuf can only reference data
> -			 * for one or partial of one desc buff.
> -			 */
> -			mbuf_avail = cpy_len;
> -		} else {
> -			if (likely(cpy_len > MAX_BATCH_LEN ||
> -				   vq->batch_copy_nb_elems >= vq->size ||
> -				   (hdr && cur == m))) {
> -				rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
> -								   mbuf_offset),
> -					   (void *)((uintptr_t)(buf_addr +
> -							   buf_offset)),
> -					   cpy_len);
> -			} else {
> -				batch_copy[vq->batch_copy_nb_elems].dst =
> -					rte_pktmbuf_mtod_offset(cur, void *,
> -								mbuf_offset);
> -				batch_copy[vq->batch_copy_nb_elems].src =
> +		if (likely(cpy_len > MAX_BATCH_LEN ||
> +					vq->batch_copy_nb_elems >= vq->size ||
> +					(hdr && cur == m))) {
> +			rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *,
> +						mbuf_offset),
>  					(void *)((uintptr_t)(buf_addr +
> -								buf_offset));
> -				batch_copy[vq->batch_copy_nb_elems].len =
> -					cpy_len;
> -				vq->batch_copy_nb_elems++;
> -			}
> +							buf_offset)), cpy_len);
> +		} else {
> +			batch_copy[vq->batch_copy_nb_elems].dst =
> +				rte_pktmbuf_mtod_offset(cur, void *,
> +						mbuf_offset);
> +			batch_copy[vq->batch_copy_nb_elems].src =
> +				(void *)((uintptr_t)(buf_addr + buf_offset));
> +			batch_copy[vq->batch_copy_nb_elems].len = cpy_len;
> +			vq->batch_copy_nb_elems++;
>  		}
> 
>  		mbuf_avail  -= cpy_len;
> @@ -2067,7 +2039,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  				break;
> 
>  			buf_addr = buf_vec[vec_idx].buf_addr;
> -			buf_iova = buf_vec[vec_idx].buf_iova;
>  			buf_len = buf_vec[vec_idx].buf_len;
> 
>  			buf_offset = 0;
> @@ -2089,8 +2060,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  				error = -1;
>  				goto out;
>  			}
> -			if (unlikely(dev->dequeue_zero_copy))
> -				rte_mbuf_refcnt_update(cur, 1);
> 
>  			prev->next = cur;
>  			prev->data_len = mbuf_offset;
> @@ -2114,37 +2083,6 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	return error;
>  }
> 
> -static __rte_always_inline struct zcopy_mbuf *
> -get_zmbuf(struct vhost_virtqueue *vq)
> -{
> -	uint16_t i;
> -	uint16_t last;
> -	int tries = 0;
> -
> -	/* search [last_zmbuf_idx, zmbuf_size) */
> -	i = vq->last_zmbuf_idx;
> -	last = vq->zmbuf_size;
> -
> -again:
> -	for (; i < last; i++) {
> -		if (vq->zmbufs[i].in_use == 0) {
> -			vq->last_zmbuf_idx = i + 1;
> -			vq->zmbufs[i].in_use = 1;
> -			return &vq->zmbufs[i];
> -		}
> -	}
> -
> -	tries++;
> -	if (tries == 1) {
> -		/* search [0, last_zmbuf_idx) */
> -		i = 0;
> -		last = vq->last_zmbuf_idx;
> -		goto again;
> -	}
> -
> -	return NULL;
> -}
> -
>  static void
>  virtio_dev_extbuf_free(void *addr __rte_unused, void *opaque)
>  {
> @@ -2244,30 +2182,6 @@ virtio_dev_tx_split(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  	uint16_t dropped = 0;
>  	static bool allocerr_warned;
> 
> -	if (unlikely(dev->dequeue_zero_copy)) {
> -		struct zcopy_mbuf *zmbuf, *next;
> -
> -		for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
> -		     zmbuf != NULL; zmbuf = next) {
> -			next = TAILQ_NEXT(zmbuf, next);
> -
> -			if (mbuf_is_consumed(zmbuf->mbuf)) {
> -				update_shadow_used_ring_split(vq,
> -						zmbuf->desc_idx, 0);
> -				TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
> -				restore_mbuf(zmbuf->mbuf);
> -				rte_pktmbuf_free(zmbuf->mbuf);
> -				put_zmbuf(zmbuf);
> -				vq->nr_zmbuf -= 1;
> -			}
> -		}
> -
> -		if (likely(vq->shadow_used_idx)) {
> -			flush_shadow_used_ring_split(dev, vq);
> -			vhost_vring_call_split(dev, vq);
> -		}
> -	}
> -
>  	/*
>  	 * The ordering between avail index and
>  	 * desc reads needs to be enforced.
> @@ -2300,8 +2214,7 @@ virtio_dev_tx_split(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  						VHOST_ACCESS_RO) < 0))
>  			break;
> 
> -		if (likely(dev->dequeue_zero_copy == 0))
> -			update_shadow_used_ring_split(vq, head_idx, 0);
> +		update_shadow_used_ring_split(vq, head_idx, 0);
> 
>  		pkts[i] = virtio_dev_pktmbuf_alloc(dev, mbuf_pool, buf_len);
>  		if (unlikely(pkts[i] == NULL)) {
> @@ -2335,42 +2248,16 @@ virtio_dev_tx_split(struct virtio_net *dev, struct
> vhost_virtqueue *vq,
>  			i++;
>  			break;
>  		}
> -
> -		if (unlikely(dev->dequeue_zero_copy)) {
> -			struct zcopy_mbuf *zmbuf;
> -
> -			zmbuf = get_zmbuf(vq);
> -			if (!zmbuf) {
> -				rte_pktmbuf_free(pkts[i]);
> -				dropped += 1;
> -				i++;
> -				break;
> -			}
> -			zmbuf->mbuf = pkts[i];
> -			zmbuf->desc_idx = head_idx;
> -
> -			/*
> -			 * Pin lock the mbuf; we will check later to see
> -			 * whether the mbuf is freed (when we are the last
> -			 * user) or not. If that's the case, we then could
> -			 * update the used ring safely.
> -			 */
> -			rte_mbuf_refcnt_update(pkts[i], 1);
> -
> -			vq->nr_zmbuf += 1;
> -			TAILQ_INSERT_TAIL(&vq->zmbuf_list, zmbuf, next);
> -		}
>  	}
> +
>  	vq->last_avail_idx += i;
> 
> -	if (likely(dev->dequeue_zero_copy == 0)) {
> -		do_data_copy_dequeue(vq);
> -		if (unlikely(i < count))
> -			vq->shadow_used_idx = i;
> -		if (likely(vq->shadow_used_idx)) {
> -			flush_shadow_used_ring_split(dev, vq);
> -			vhost_vring_call_split(dev, vq);
> -		}
> +	do_data_copy_dequeue(vq);
> +	if (unlikely(i < count))
> +		vq->shadow_used_idx = i;
> +	if (likely(vq->shadow_used_idx)) {
> +		flush_shadow_used_ring_split(dev, vq);
> +		vhost_vring_call_split(dev, vq);
>  	}
> 
>  	return (i - dropped);
> @@ -2570,162 +2457,6 @@ virtio_dev_tx_single_packed(struct virtio_net *dev,
>  	return ret;
>  }
> 
> -static __rte_always_inline int
> -virtio_dev_tx_batch_packed_zmbuf(struct virtio_net *dev,
> -				 struct vhost_virtqueue *vq,
> -				 struct rte_mempool *mbuf_pool,
> -				 struct rte_mbuf **pkts)
> -{
> -	struct zcopy_mbuf *zmbufs[PACKED_BATCH_SIZE];
> -	uintptr_t desc_addrs[PACKED_BATCH_SIZE];
> -	uint16_t ids[PACKED_BATCH_SIZE];
> -	uint16_t i;
> -
> -	uint16_t avail_idx = vq->last_avail_idx;
> -
> -	if (vhost_reserve_avail_batch_packed(dev, vq, mbuf_pool, pkts,
> -					     avail_idx, desc_addrs, ids))
> -		return -1;
> -
> -	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
> -		zmbufs[i] = get_zmbuf(vq);
> -
> -	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
> -		if (!zmbufs[i])
> -			goto free_pkt;
> -	}
> -
> -	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE) {
> -		zmbufs[i]->mbuf = pkts[i];
> -		zmbufs[i]->desc_idx = ids[i];
> -		zmbufs[i]->desc_count = 1;
> -	}
> -
> -	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
> -		rte_mbuf_refcnt_update(pkts[i], 1);
> -
> -	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
> -		TAILQ_INSERT_TAIL(&vq->zmbuf_list, zmbufs[i], next);
> -
> -	vq->nr_zmbuf += PACKED_BATCH_SIZE;
> -	vq_inc_last_avail_packed(vq, PACKED_BATCH_SIZE);
> -
> -	return 0;
> -
> -free_pkt:
> -	vhost_for_each_try_unroll(i, 0, PACKED_BATCH_SIZE)
> -		rte_pktmbuf_free(pkts[i]);
> -
> -	return -1;
> -}
> -
> -static __rte_always_inline int
> -virtio_dev_tx_single_packed_zmbuf(struct virtio_net *dev,
> -				  struct vhost_virtqueue *vq,
> -				  struct rte_mempool *mbuf_pool,
> -				  struct rte_mbuf **pkts)
> -{
> -	uint16_t buf_id, desc_count;
> -	struct zcopy_mbuf *zmbuf;
> -
> -	if (vhost_dequeue_single_packed(dev, vq, mbuf_pool, pkts, &buf_id,
> -					&desc_count))
> -		return -1;
> -
> -	zmbuf = get_zmbuf(vq);
> -	if (!zmbuf) {
> -		rte_pktmbuf_free(*pkts);
> -		return -1;
> -	}
> -	zmbuf->mbuf = *pkts;
> -	zmbuf->desc_idx = buf_id;
> -	zmbuf->desc_count = desc_count;
> -
> -	rte_mbuf_refcnt_update(*pkts, 1);
> -
> -	vq->nr_zmbuf += 1;
> -	TAILQ_INSERT_TAIL(&vq->zmbuf_list, zmbuf, next);
> -
> -	vq_inc_last_avail_packed(vq, desc_count);
> -	return 0;
> -}
> -
> -static __rte_always_inline void
> -free_zmbuf(struct vhost_virtqueue *vq)
> -{
> -	struct zcopy_mbuf *next = NULL;
> -	struct zcopy_mbuf *zmbuf;
> -
> -	for (zmbuf = TAILQ_FIRST(&vq->zmbuf_list);
> -	     zmbuf != NULL; zmbuf = next) {
> -		next = TAILQ_NEXT(zmbuf, next);
> -
> -		uint16_t last_used_idx = vq->last_used_idx;
> -
> -		if (mbuf_is_consumed(zmbuf->mbuf)) {
> -			uint16_t flags;
> -			flags = vq->desc_packed[last_used_idx].flags;
> -			if (vq->used_wrap_counter) {
> -				flags |= VRING_DESC_F_USED;
> -				flags |= VRING_DESC_F_AVAIL;
> -			} else {
> -				flags &= ~VRING_DESC_F_USED;
> -				flags &= ~VRING_DESC_F_AVAIL;
> -			}
> -
> -			vq->desc_packed[last_used_idx].id = zmbuf->desc_idx;
> -			vq->desc_packed[last_used_idx].len = 0;
> -
> -			rte_smp_wmb();
> -			vq->desc_packed[last_used_idx].flags = flags;
> -
> -			vq_inc_last_used_packed(vq, zmbuf->desc_count);
> -
> -			TAILQ_REMOVE(&vq->zmbuf_list, zmbuf, next);
> -			restore_mbuf(zmbuf->mbuf);
> -			rte_pktmbuf_free(zmbuf->mbuf);
> -			put_zmbuf(zmbuf);
> -			vq->nr_zmbuf -= 1;
> -		}
> -	}
> -}
> -
> -static __rte_noinline uint16_t
> -virtio_dev_tx_packed_zmbuf(struct virtio_net *dev,
> -			   struct vhost_virtqueue *__rte_restrict vq,
> -			   struct rte_mempool *mbuf_pool,
> -			   struct rte_mbuf **__rte_restrict pkts,
> -			   uint32_t count)
> -{
> -	uint32_t pkt_idx = 0;
> -	uint32_t remained = count;
> -
> -	free_zmbuf(vq);
> -
> -	do {
> -		if (remained >= PACKED_BATCH_SIZE) {
> -			if (!virtio_dev_tx_batch_packed_zmbuf(dev, vq,
> -				mbuf_pool, &pkts[pkt_idx])) {
> -				pkt_idx += PACKED_BATCH_SIZE;
> -				remained -= PACKED_BATCH_SIZE;
> -				continue;
> -			}
> -		}
> -
> -		if (virtio_dev_tx_single_packed_zmbuf(dev, vq, mbuf_pool,
> -						      &pkts[pkt_idx]))
> -			break;
> -		pkt_idx++;
> -		remained--;
> -
> -	} while (remained);
> -
> -	if (pkt_idx)
> -		vhost_vring_call_packed(dev, vq);
> -
> -	return pkt_idx;
> -}
> -
>  static __rte_noinline uint16_t
>  virtio_dev_tx_packed(struct virtio_net *dev,
>  		     struct vhost_virtqueue *__rte_restrict vq,
> @@ -2841,14 +2572,9 @@ rte_vhost_dequeue_burst(int vid, uint16_t queue_id,
>  		count -= 1;
>  	}
> 
> -	if (vq_is_packed(dev)) {
> -		if (unlikely(dev->dequeue_zero_copy))
> -			count = virtio_dev_tx_packed_zmbuf(dev, vq, mbuf_pool,
> -							   pkts, count);
> -		else
> -			count = virtio_dev_tx_packed(dev, vq, mbuf_pool, pkts,
> -						     count);
> -	} else
> +	if (vq_is_packed(dev))
> +		count = virtio_dev_tx_packed(dev, vq, mbuf_pool, pkts, count);
> +	else
>  		count = virtio_dev_tx_split(dev, vq, mbuf_pool, pkts, count);
> 
>  out:
> --
> 2.26.2


  reply	other threads:[~2020-09-23  5:44 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-15 13:35 [dpdk-dev] [PATCH 0/4] pick Maxime Coquelin
2020-09-15 13:35 ` [dpdk-dev] [PATCH 1/4] net/vhost: remove dequeue zero-copy support Maxime Coquelin
2020-09-23  5:41   ` Xia, Chenbo
2020-09-15 13:35 ` [dpdk-dev] [PATCH 2/4] examples/vhost_crypto: use vhost async-copy flag Maxime Coquelin
2020-09-23  5:43   ` Xia, Chenbo
2020-09-15 13:35 ` [dpdk-dev] [PATCH 3/4] examples/vhost: remove dequeue zero-copy support Maxime Coquelin
2020-09-23  5:43   ` Xia, Chenbo
2020-09-15 13:35 ` [dpdk-dev] [PATCH 4/4] vhost: " Maxime Coquelin
2020-09-23  5:44   ` Xia, Chenbo [this message]
2020-09-15 13:41 ` [dpdk-dev] [PATCH 0/4] vhost: remove dequeue zero-copy support (was: pick) Maxime Coquelin

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