vhost_net: basic polling support
This patch tries to poll for new added tx buffer or socket receive queue for a while at the end of tx/rx processing. The maximum time spent on polling were specified through a new kind of vring ioctl. Signed-off-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Родитель
d4a60603fa
Коммит
0308813724
|
@ -287,6 +287,43 @@ static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
|
|||
rcu_read_unlock_bh();
|
||||
}
|
||||
|
||||
static inline unsigned long busy_clock(void)
|
||||
{
|
||||
return local_clock() >> 10;
|
||||
}
|
||||
|
||||
static bool vhost_can_busy_poll(struct vhost_dev *dev,
|
||||
unsigned long endtime)
|
||||
{
|
||||
return likely(!need_resched()) &&
|
||||
likely(!time_after(busy_clock(), endtime)) &&
|
||||
likely(!signal_pending(current)) &&
|
||||
!vhost_has_work(dev);
|
||||
}
|
||||
|
||||
static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
|
||||
struct vhost_virtqueue *vq,
|
||||
struct iovec iov[], unsigned int iov_size,
|
||||
unsigned int *out_num, unsigned int *in_num)
|
||||
{
|
||||
unsigned long uninitialized_var(endtime);
|
||||
int r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
|
||||
out_num, in_num, NULL, NULL);
|
||||
|
||||
if (r == vq->num && vq->busyloop_timeout) {
|
||||
preempt_disable();
|
||||
endtime = busy_clock() + vq->busyloop_timeout;
|
||||
while (vhost_can_busy_poll(vq->dev, endtime) &&
|
||||
vhost_vq_avail_empty(vq->dev, vq))
|
||||
cpu_relax_lowlatency();
|
||||
preempt_enable();
|
||||
r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov),
|
||||
out_num, in_num, NULL, NULL);
|
||||
}
|
||||
|
||||
return r;
|
||||
}
|
||||
|
||||
/* Expects to be always run from workqueue - which acts as
|
||||
* read-size critical section for our kind of RCU. */
|
||||
static void handle_tx(struct vhost_net *net)
|
||||
|
@ -331,10 +368,9 @@ static void handle_tx(struct vhost_net *net)
|
|||
% UIO_MAXIOV == nvq->done_idx))
|
||||
break;
|
||||
|
||||
head = vhost_get_vq_desc(vq, vq->iov,
|
||||
ARRAY_SIZE(vq->iov),
|
||||
&out, &in,
|
||||
NULL, NULL);
|
||||
head = vhost_net_tx_get_vq_desc(net, vq, vq->iov,
|
||||
ARRAY_SIZE(vq->iov),
|
||||
&out, &in);
|
||||
/* On error, stop handling until the next kick. */
|
||||
if (unlikely(head < 0))
|
||||
break;
|
||||
|
@ -435,6 +471,38 @@ static int peek_head_len(struct sock *sk)
|
|||
return len;
|
||||
}
|
||||
|
||||
static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk)
|
||||
{
|
||||
struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
|
||||
struct vhost_virtqueue *vq = &nvq->vq;
|
||||
unsigned long uninitialized_var(endtime);
|
||||
int len = peek_head_len(sk);
|
||||
|
||||
if (!len && vq->busyloop_timeout) {
|
||||
/* Both tx vq and rx socket were polled here */
|
||||
mutex_lock(&vq->mutex);
|
||||
vhost_disable_notify(&net->dev, vq);
|
||||
|
||||
preempt_disable();
|
||||
endtime = busy_clock() + vq->busyloop_timeout;
|
||||
|
||||
while (vhost_can_busy_poll(&net->dev, endtime) &&
|
||||
skb_queue_empty(&sk->sk_receive_queue) &&
|
||||
vhost_vq_avail_empty(&net->dev, vq))
|
||||
cpu_relax_lowlatency();
|
||||
|
||||
preempt_enable();
|
||||
|
||||
if (vhost_enable_notify(&net->dev, vq))
|
||||
vhost_poll_queue(&vq->poll);
|
||||
mutex_unlock(&vq->mutex);
|
||||
|
||||
len = peek_head_len(sk);
|
||||
}
|
||||
|
||||
return len;
|
||||
}
|
||||
|
||||
/* This is a multi-buffer version of vhost_get_desc, that works if
|
||||
* vq has read descriptors only.
|
||||
* @vq - the relevant virtqueue
|
||||
|
@ -553,7 +621,7 @@ static void handle_rx(struct vhost_net *net)
|
|||
vq->log : NULL;
|
||||
mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
|
||||
|
||||
while ((sock_len = peek_head_len(sock->sk))) {
|
||||
while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk))) {
|
||||
sock_len += sock_hlen;
|
||||
vhost_len = sock_len + vhost_hlen;
|
||||
headcount = get_rx_bufs(vq, vq->heads, vhost_len,
|
||||
|
|
|
@ -303,6 +303,7 @@ static void vhost_vq_reset(struct vhost_dev *dev,
|
|||
vq->memory = NULL;
|
||||
vhost_reset_is_le(vq);
|
||||
vhost_disable_cross_endian(vq);
|
||||
vq->busyloop_timeout = 0;
|
||||
}
|
||||
|
||||
static int vhost_worker(void *data)
|
||||
|
@ -937,6 +938,19 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
|
|||
case VHOST_GET_VRING_ENDIAN:
|
||||
r = vhost_get_vring_endian(vq, idx, argp);
|
||||
break;
|
||||
case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
|
||||
if (copy_from_user(&s, argp, sizeof(s))) {
|
||||
r = -EFAULT;
|
||||
break;
|
||||
}
|
||||
vq->busyloop_timeout = s.num;
|
||||
break;
|
||||
case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
|
||||
s.index = idx;
|
||||
s.num = vq->busyloop_timeout;
|
||||
if (copy_to_user(argp, &s, sizeof(s)))
|
||||
r = -EFAULT;
|
||||
break;
|
||||
default:
|
||||
r = -ENOIOCTLCMD;
|
||||
}
|
||||
|
|
|
@ -115,6 +115,7 @@ struct vhost_virtqueue {
|
|||
/* Ring endianness requested by userspace for cross-endian support. */
|
||||
bool user_be;
|
||||
#endif
|
||||
u32 busyloop_timeout;
|
||||
};
|
||||
|
||||
struct vhost_dev {
|
||||
|
|
|
@ -126,6 +126,12 @@ struct vhost_memory {
|
|||
#define VHOST_SET_VRING_CALL _IOW(VHOST_VIRTIO, 0x21, struct vhost_vring_file)
|
||||
/* Set eventfd to signal an error */
|
||||
#define VHOST_SET_VRING_ERR _IOW(VHOST_VIRTIO, 0x22, struct vhost_vring_file)
|
||||
/* Set busy loop timeout (in us) */
|
||||
#define VHOST_SET_VRING_BUSYLOOP_TIMEOUT _IOW(VHOST_VIRTIO, 0x23, \
|
||||
struct vhost_vring_state)
|
||||
/* Get busy loop timeout (in us) */
|
||||
#define VHOST_GET_VRING_BUSYLOOP_TIMEOUT _IOW(VHOST_VIRTIO, 0x24, \
|
||||
struct vhost_vring_state)
|
||||
|
||||
/* VHOST_NET specific defines */
|
||||
|
||||
|
|
Загрузка…
Ссылка в новой задаче