From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: Tiwei Bie <tiwei.bie@intel.com>
Cc: zhihong.wang@intel.com, jfreimann@redhat.com, dev@dpdk.org,
mst@redhat.com, jasowang@redhat.com, wexu@redhat.com
Subject: Re: [dpdk-dev] [PATCH v6 11/15] vhost: add vector filling support for packed ring
Date: Wed, 4 Jul 2018 18:18:15 +0200 [thread overview]
Message-ID: <eac5ee3c-c015-b173-31f6-b0db520c31b0@redhat.com> (raw)
In-Reply-To: <20180704055307.GD28826@debian>
On 07/04/2018 07:53 AM, Tiwei Bie wrote:
> On Mon, Jul 02, 2018 at 10:16:25AM +0200, Maxime Coquelin wrote:
> [...]
>> +static __rte_always_inline int
>> +fill_vec_buf_packed_indirect(struct virtio_net *dev,
>> + struct vhost_virtqueue *vq,
>> + struct vring_desc_packed *desc, uint16_t *vec_idx,
>> + struct buf_vector *buf_vec, uint16_t *len, uint8_t perm)
>> +{
>> + uint16_t i;
>> + uint32_t nr_decs;
>> + uint16_t vec_id = *vec_idx;
>> + uint64_t dlen;
>> + struct vring_desc_packed *descs, *idescs = NULL;
>> +
>> + dlen = desc->len;
>> + descs = (struct vring_desc_packed *)(uintptr_t)
>> + vhost_iova_to_vva(dev, vq, desc->addr, &dlen, VHOST_ACCESS_RO);
>> + if (unlikely(!descs))
>> + return -1;
>> +
>> + if (unlikely(dlen < desc->len)) {
>> + /*
>> + * The indirect desc table is not contiguous
>> + * in process VA space, we have to copy it.
>> + */
>> + idescs = alloc_copy_ind_table(dev, vq, desc->addr, desc->len);
>> + if (unlikely(!idescs))
>> + return -1;
>> +
>> + descs = idescs;
>> + }
>> +
>> + nr_decs = desc->len / sizeof(struct vring_desc_packed);
>
> s/nr_decs = /nr_desc = /
Fixed.
>
>
>> + if (unlikely(nr_decs >= vq->size)) {
>> + free_ind_table(idescs);
>> + return -1;
>> + }
> [...]
>> +
>> +static inline int
>> +fill_vec_buf_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
>> + uint16_t avail_idx, uint16_t *desc_count,
>> + struct buf_vector *buf_vec, uint16_t *vec_idx,
>> + uint16_t *buf_id, uint16_t *len, uint8_t perm)
>> +{
>> + bool wrap_counter = vq->avail_wrap_counter;
>> + struct vring_desc_packed *descs = vq->desc_packed;
>> + uint16_t vec_id = *vec_idx;
>> +
>> + if (avail_idx < vq->last_avail_idx)
>> + wrap_counter ^= 1;
>
> In which case avail_idx will be less than vq->last_avail_idx
> and we need to wrap the wrap_counter?
In the receive mergeable case, it can happen (see patch 12):
static inline int
reserve_avail_buf_packed(struct virtio_net *dev, struct vhost_virtqueue *vq,
uint32_t size, struct buf_vector *buf_vec,
uint16_t *nr_vec, uint16_t *num_buffers,
uint16_t *nr_descs)
{
uint16_t avail_idx;
uint16_t vec_idx = 0;
uint16_t max_tries, tries = 0;
uint16_t buf_id = 0;
uint16_t len = 0;
uint16_t desc_count;
*num_buffers = 0;
avail_idx = vq->last_avail_idx;
if (rxvq_is_mergeable(dev))
max_tries = vq->size;
else
max_tries = 1;
while (size > 0) {
if (unlikely(fill_vec_buf_packed(dev, vq,
avail_idx, &desc_count,
buf_vec, &vec_idx,
&buf_id, &len,
VHOST_ACCESS_RO) < 0))
return -1;
len = RTE_MIN(len, size);
update_shadow_used_ring_packed(vq, buf_id, len, desc_count);
size -= len;
avail_idx += desc_count;
if (avail_idx >= vq->size)
avail_idx -= vq->size;
*nr_descs += desc_count;
tries++;
*num_buffers += 1;
/*
* if we tried all available ring items, and still
* can't get enough buf, it means something abnormal
* happened.
*/
if (unlikely(tries > max_tries))
return -1;
}
*nr_vec = vec_idx;
return 0;
}
>> +
>> + if (unlikely(!desc_is_avail(&descs[avail_idx], wrap_counter)))
>> + return -1;
>> +
>> + *desc_count = 0;
>> +
>> + while (1) {
>> + if (unlikely(vec_id >= BUF_VECTOR_MAX))
>> + return -1;
>> +
>> + *desc_count += 1;
>> + *buf_id = descs[avail_idx].index;
>> +
>> + if (descs[avail_idx].flags & VRING_DESC_F_INDIRECT) {
>> + if (unlikely(fill_vec_buf_packed_indirect(dev, vq,
>> + &descs[avail_idx],
>> + &vec_id, buf_vec,
>> + len, perm) < 0))
>> + return -1;
>> + } else {
>> + *len += descs[avail_idx].len;
>> +
>> + if (unlikely(map_one_desc(dev, vq, buf_vec, &vec_id,
>> + descs[avail_idx].addr,
>> + descs[avail_idx].len,
>> + perm)))
>> + return -1;
>> + }
>> +
>> + if ((descs[avail_idx].flags & VRING_DESC_F_NEXT) == 0)
>> + break;
>> +
>> + if (++avail_idx >= vq->size) {
>> + avail_idx -= vq->size;
>> + wrap_counter ^= 1;
>> + }
>> + }
>> +
>> + *vec_idx = vec_id;
>> +
>> + return 0;
>> +}
> [...]
>
next prev parent reply other threads:[~2018-07-04 16:18 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-02 8:16 [dpdk-dev] [PATCH v6 00/15] Vhost: add support to packed ring layout Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 01/15] vhost: add virtio packed virtqueue defines Maxime Coquelin
2018-07-04 5:37 ` Tiwei Bie
2018-07-04 16:03 ` Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 02/15] vhost: add helpers for packed virtqueues Maxime Coquelin
2018-07-04 5:39 ` Tiwei Bie
2018-07-04 16:03 ` Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 03/15] vhost: vring address setup for packed queues Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 04/15] vhost: clear shadow used table index at flush time Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 05/15] vhost: make indirect desc table copy desc type agnostic Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 06/15] vhost: clear batch copy index at copy time Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 07/15] vhost: extract split ring handling from Rx and Tx functions Maxime Coquelin
2018-07-04 6:51 ` Tiwei Bie
2018-07-04 21:04 ` Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 08/15] vhost: append shadow used ring function names with split Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 09/15] vhost: add shadow used ring support for packed rings Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 10/15] vhost: create descriptor mapping function Maxime Coquelin
2018-07-04 5:56 ` Tiwei Bie
2018-07-04 16:18 ` Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 11/15] vhost: add vector filling support for packed ring Maxime Coquelin
2018-07-04 5:53 ` Tiwei Bie
2018-07-04 16:18 ` Maxime Coquelin [this message]
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 12/15] vhost: add Rx " Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 13/15] vhost: add Tx " Maxime Coquelin
2018-07-04 5:45 ` Tiwei Bie
2018-07-04 16:09 ` Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 14/15] vhost: add notification " Maxime Coquelin
2018-07-03 5:57 ` Jason Wang
2018-07-03 6:43 ` Maxime Coquelin
2018-07-03 6:06 ` Jason Wang
2018-07-04 16:02 ` Maxime Coquelin
2018-07-04 6:25 ` Tiwei Bie
2018-07-04 20:20 ` Maxime Coquelin
2018-07-02 8:16 ` [dpdk-dev] [PATCH v6 15/15] vhost: advertize packed ring layout support Maxime Coquelin
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