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Merge branch 'allocate-multiple-skbuffs-on-tx'

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Arseniy Krasnov says:

====================
allocate multiple skbuffs on tx

This adds small optimization for tx path: instead of allocating single
skbuff on every call to transport, allocate multiple skbuff's until
credit space allows, thus trying to send as much as possible data without
return to af_vsock.c.

Also this patchset includes second patch which adds check and return from
'virtio_transport_get_credit()' and 'virtio_transport_put_credit()' when
these functions are called with 0 argument. This is needed, because zero
argument makes both functions to behave as no-effect, but both of them
always tries to acquire spinlock. Moreover, first patch always calls
function 'virtio_transport_put_credit()' with zero argument in case of
successful packet transmission.
====================

Link: https://lore.kernel.org/r/b0d15942-65ba-3a32-ba8d-fed64332d8f6@sberdevices.ru
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Paolo Abeni 2023-03-28 12:03:54 +02:00
commit d8b0c963e9
1 changed files with 49 additions and 14 deletions
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63
net/vmw_vsock/virtio_transport_common.c
View File

@ -196,7 +196,8 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
const struct virtio_transport *t_ops;
struct virtio_vsock_sock *vvs;
u32 pkt_len = info->pkt_len;
struct sk_buff *skb;
u32 rest_len;
int ret;
info->type = virtio_transport_get_type(sk_vsock(vsk));
@ -216,10 +217,6 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
vvs = vsk->trans;
/* we can send less than pkt_len bytes */
if (pkt_len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE)
pkt_len = VIRTIO_VSOCK_MAX_PKT_BUF_SIZE;
/* virtio_transport_get_credit might return less than pkt_len credit */
pkt_len = virtio_transport_get_credit(vvs, pkt_len);
@ -227,17 +224,49 @@ static int virtio_transport_send_pkt_info(struct vsock_sock *vsk,
if (pkt_len == 0 && info->op == VIRTIO_VSOCK_OP_RW)
return pkt_len;
skb = virtio_transport_alloc_skb(info, pkt_len,
src_cid, src_port,
dst_cid, dst_port);
if (!skb) {
virtio_transport_put_credit(vvs, pkt_len);
return -ENOMEM;
}
rest_len = pkt_len;
virtio_transport_inc_tx_pkt(vvs, skb);
do {
struct sk_buff *skb;
size_t skb_len;
return t_ops->send_pkt(skb);
skb_len = min_t(u32, VIRTIO_VSOCK_MAX_PKT_BUF_SIZE, rest_len);
skb = virtio_transport_alloc_skb(info, skb_len,
src_cid, src_port,
dst_cid, dst_port);
if (!skb) {
ret = -ENOMEM;
break;
}
virtio_transport_inc_tx_pkt(vvs, skb);
ret = t_ops->send_pkt(skb);
if (ret < 0)
break;
/* Both virtio and vhost 'send_pkt()' returns 'skb_len',
* but for reliability use 'ret' instead of 'skb_len'.
* Also if partial send happens (e.g. 'ret' != 'skb_len')
* somehow, we break this loop, but account such returned
* value in 'virtio_transport_put_credit()'.
*/
rest_len -= ret;
if (WARN_ONCE(ret != skb_len,
"'send_pkt()' returns %i, but %zu expected\n",
ret, skb_len))
break;
} while (rest_len);
virtio_transport_put_credit(vvs, rest_len);
/* Return number of bytes, if any data has been sent. */
if (rest_len != pkt_len)
ret = pkt_len - rest_len;
return ret;
}
static bool virtio_transport_inc_rx_pkt(struct virtio_vsock_sock *vvs,
@ -273,6 +302,9 @@ u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 credit)
{
u32 ret;
if (!credit)
return 0;
spin_lock_bh(&vvs->tx_lock);
ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt);
if (ret > credit)
@ -286,6 +318,9 @@ EXPORT_SYMBOL_GPL(virtio_transport_get_credit);
void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 credit)
{
if (!credit)
return;
spin_lock_bh(&vvs->tx_lock);
vvs->tx_cnt -= credit;
spin_unlock_bh(&vvs->tx_lock);