diff options
| -rw-r--r-- | drivers/vhost/net.c | 78 | ||||
| -rw-r--r-- | drivers/vhost/vhost.c | 14 | ||||
| -rw-r--r-- | drivers/vhost/vhost.h | 1 | ||||
| -rw-r--r-- | include/uapi/linux/vhost.h | 6 |
4 files changed, 94 insertions, 5 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 7bd75ff8be26..f744eeb3e2b4 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -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, diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 97f26f0aab40..669fef1e2bb6 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -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; } diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index af5af773bf7a..d36d8beb3351 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -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 { diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h index ab3731917bac..61a8777178c6 100644 --- a/include/uapi/linux/vhost.h +++ b/include/uapi/linux/vhost.h @@ -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 */ |