From: Jason Wang <jasowang@redhat.com>
To: kvm@vger.kernel.org, mst@redhat.com,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: RAPOPORT@il.ibm.com, yang.zhang.wz@gmail.com,
Jason Wang <jasowang@redhat.com>
Subject: [PATCH V3 3/3] vhost_net: basic polling support
Date: Fri, 26 Feb 2016 16:42:44 +0800 [thread overview]
Message-ID: <1456476164-17242-4-git-send-email-jasowang@redhat.com> (raw)
In-Reply-To: <1456476164-17242-1-git-send-email-jasowang@redhat.com>
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>
---
drivers/vhost/net.c | 79 +++++++++++++++++++++++++++++++++++++++++++---
drivers/vhost/vhost.c | 14 ++++++++
drivers/vhost/vhost.h | 1 +
include/uapi/linux/vhost.h | 6 ++++
4 files changed, 95 insertions(+), 5 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 9eda69e..c91af93 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -287,6 +287,44 @@ 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) &&
+ single_task_running();
+}
+
+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();
+ 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 +369,9 @@ 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 +472,38 @@ 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();
+
+ 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 +622,7 @@ 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 c4ff9f2..5abfce9 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -285,6 +285,7 @@ static void vhost_vq_reset(struct vhost_dev *dev,
vq->memory = NULL;
vq->is_le = virtio_legacy_is_little_endian();
vhost_vq_reset_user_be(vq);
+ vq->busyloop_timeout = 0;
}
static int vhost_worker(void *data)
@@ -919,6 +920,19 @@ 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 a7a43f0..9a02158 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 ab373191..61a8777 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 */
--
2.5.0
WARNING: multiple messages have this Message-ID (diff)
From: Jason Wang <jasowang@redhat.com>
To: kvm@vger.kernel.org, mst@redhat.com,
virtualization@lists.linux-foundation.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: yang.zhang.wz@gmail.com, RAPOPORT@il.ibm.com
Subject: [PATCH V3 3/3] vhost_net: basic polling support
Date: Fri, 26 Feb 2016 16:42:44 +0800 [thread overview]
Message-ID: <1456476164-17242-4-git-send-email-jasowang@redhat.com> (raw)
In-Reply-To: <1456476164-17242-1-git-send-email-jasowang@redhat.com>
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>
---
drivers/vhost/net.c | 79 +++++++++++++++++++++++++++++++++++++++++++---
drivers/vhost/vhost.c | 14 ++++++++
drivers/vhost/vhost.h | 1 +
include/uapi/linux/vhost.h | 6 ++++
4 files changed, 95 insertions(+), 5 deletions(-)
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 9eda69e..c91af93 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -287,6 +287,44 @@ 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) &&
+ single_task_running();
+}
+
+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();
+ 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 +369,9 @@ 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 +472,38 @@ 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();
+
+ 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 +622,7 @@ 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 c4ff9f2..5abfce9 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -285,6 +285,7 @@ static void vhost_vq_reset(struct vhost_dev *dev,
vq->memory = NULL;
vq->is_le = virtio_legacy_is_little_endian();
vhost_vq_reset_user_be(vq);
+ vq->busyloop_timeout = 0;
}
static int vhost_worker(void *data)
@@ -919,6 +920,19 @@ 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 a7a43f0..9a02158 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 ab373191..61a8777 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 */
--
2.5.0
next prev parent reply other threads:[~2016-02-26 8:43 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-26 8:42 [PATCH V3 0/3] basic busy polling support for vhost_net Jason Wang
2016-02-26 8:42 ` Jason Wang
2016-02-26 8:42 ` [PATCH V3 1/3] vhost: introduce vhost_has_work() Jason Wang
2016-02-26 8:42 ` Jason Wang
2016-02-26 8:42 ` [PATCH V3 2/3] vhost: introduce vhost_vq_avail_empty() Jason Wang
2016-02-26 8:42 ` Jason Wang
2016-02-26 8:42 ` Jason Wang [this message]
2016-02-26 8:42 ` [PATCH V3 3/3] vhost_net: basic polling support Jason Wang
2016-02-28 14:09 ` Michael S. Tsirkin
2016-02-28 14:09 ` Michael S. Tsirkin
2016-02-29 5:15 ` Jason Wang
2016-02-29 5:15 ` Jason Wang
2016-02-29 9:03 ` Michael S. Tsirkin
2016-02-29 9:03 ` Michael S. Tsirkin
2016-02-28 21:56 ` Christian Borntraeger
2016-02-28 21:56 ` Christian Borntraeger
2016-02-29 5:17 ` Jason Wang
2016-02-29 5:17 ` Jason Wang
2016-02-26 16:45 ` [PATCH V3 0/3] basic busy polling support for vhost_net David Miller
2016-02-26 16:45 ` David Miller
2016-02-28 9:12 ` Michael S. Tsirkin
2016-02-28 9:12 ` Michael S. Tsirkin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1456476164-17242-4-git-send-email-jasowang@redhat.com \
--to=jasowang@redhat.com \
--cc=RAPOPORT@il.ibm.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mst@redhat.com \
--cc=netdev@vger.kernel.org \
--cc=virtualization@lists.linux-foundation.org \
--cc=yang.zhang.wz@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.