On Thu, 7 Apr 2016 18:07:44 +0200
Greg Kurz <gk...@linux.vnet.ibm.com> wrote:
> On Thu, 7 Apr 2016 12:56:24 +0800
> Jason Wang <jasow...@redhat.com> wrote:
>
> > This patch add the capability of basic vhost net busy polling which is
> > supported by recent kernel. User could configure the maximum number of
> > us that could be spent on busy polling through a new property of tap
> > "vhost-poll-us".
> >
> > Signed-off-by: Jason Wang <jasow...@redhat.com>
> > ---
>
> Thanks for this feature Jason !
>
> Tested-by: Greg Kurz <gk...@linux.vnet.ibm.com>
>
Hi !
Is there something that prevents this patch from being applied ?
> > hw/net/vhost_net.c | 2 +-
> > hw/scsi/vhost-scsi.c | 2 +-
> > hw/virtio/vhost-backend.c | 8 ++++++++
> > hw/virtio/vhost.c | 40
> > ++++++++++++++++++++++++++++++++++++++-
> > include/hw/virtio/vhost-backend.h | 3 +++
> > include/hw/virtio/vhost.h | 3 ++-
> > include/net/vhost_net.h | 1 +
> > net/tap.c | 10 ++++++++--
> > net/vhost-user.c | 1 +
> > qapi-schema.json | 6 +++++-
> > qemu-options.hx | 3 +++
> > 11 files changed, 72 insertions(+), 7 deletions(-)
> >
> > diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
> > index 6e1032f..1840c73 100644
> > --- a/hw/net/vhost_net.c
> > +++ b/hw/net/vhost_net.c
> > @@ -166,7 +166,7 @@ struct vhost_net *vhost_net_init(VhostNetOptions
> > *options)
> > }
> >
> > r = vhost_dev_init(&net->dev, options->opaque,
> > - options->backend_type);
> > + options->backend_type, options->busyloop_timeout);
> > if (r < 0) {
> > goto fail;
> > }
> > diff --git a/hw/scsi/vhost-scsi.c b/hw/scsi/vhost-scsi.c
> > index 9261d51..2a00f2f 100644
> > --- a/hw/scsi/vhost-scsi.c
> > +++ b/hw/scsi/vhost-scsi.c
> > @@ -248,7 +248,7 @@ static void vhost_scsi_realize(DeviceState *dev, Error
> > **errp)
> > s->dev.backend_features = 0;
> >
> > ret = vhost_dev_init(&s->dev, (void *)(uintptr_t)vhostfd,
> > - VHOST_BACKEND_TYPE_KERNEL);
> > + VHOST_BACKEND_TYPE_KERNEL, 0);
> > if (ret < 0) {
> > error_setg(errp, "vhost-scsi: vhost initialization failed: %s",
> > strerror(-ret));
> > diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
> > index b358902..d62372e 100644
> > --- a/hw/virtio/vhost-backend.c
> > +++ b/hw/virtio/vhost-backend.c
> > @@ -138,6 +138,12 @@ static int vhost_kernel_set_vring_call(struct
> > vhost_dev *dev,
> > return vhost_kernel_call(dev, VHOST_SET_VRING_CALL, file);
> > }
> >
> > +static int vhost_kernel_set_vring_busyloop_timeout(struct vhost_dev *dev,
> > + struct
> > vhost_vring_state *s)
> > +{
> > + return vhost_kernel_call(dev, VHOST_SET_VRING_BUSYLOOP_TIMEOUT, s);
> > +}
> > +
> > static int vhost_kernel_set_features(struct vhost_dev *dev,
> > uint64_t features)
> > {
> > @@ -185,6 +191,8 @@ static const VhostOps kernel_ops = {
> > .vhost_get_vring_base = vhost_kernel_get_vring_base,
> > .vhost_set_vring_kick = vhost_kernel_set_vring_kick,
> > .vhost_set_vring_call = vhost_kernel_set_vring_call,
> > + .vhost_set_vring_busyloop_timeout =
> > + vhost_kernel_set_vring_busyloop_timeout,
> > .vhost_set_features = vhost_kernel_set_features,
> > .vhost_get_features = vhost_kernel_get_features,
> > .vhost_set_owner = vhost_kernel_set_owner,
> > diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
> > index 4400718..ebf8b08 100644
> > --- a/hw/virtio/vhost.c
> > +++ b/hw/virtio/vhost.c
> > @@ -964,6 +964,28 @@ static void vhost_eventfd_del(MemoryListener *listener,
> > {
> > }
> >
> > +static int vhost_virtqueue_set_busyloop_timeout(struct vhost_dev *dev,
> > + int n, uint32_t timeout)
> > +{
> > + int vhost_vq_index = dev->vhost_ops->vhost_get_vq_index(dev, n);
> > + struct vhost_vring_state state = {
> > + .index = vhost_vq_index,
> > + .num = timeout,
> > + };
> > + int r;
> > +
> > + if (!dev->vhost_ops->vhost_set_vring_busyloop_timeout) {
> > + return -EINVAL;
> > + }
> > +
> > + r = dev->vhost_ops->vhost_set_vring_busyloop_timeout(dev, &state);
> > + if (r) {
> > + return r;
> > + }
> > +
> > + return 0;
> > +}
> > +
> > static int vhost_virtqueue_init(struct vhost_dev *dev,
> > struct vhost_virtqueue *vq, int n)
> > {
> > @@ -994,7 +1016,7 @@ static void vhost_virtqueue_cleanup(struct
> > vhost_virtqueue *vq)
> > }
> >
> > int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
> > - VhostBackendType backend_type)
> > + VhostBackendType backend_type, uint32_t
> > busyloop_timeout)
> > {
> > uint64_t features;
> > int i, r;
> > @@ -1035,6 +1057,17 @@ int vhost_dev_init(struct vhost_dev *hdev, void
> > *opaque,
> > goto fail_vq;
> > }
> > }
> > +
> > + if (busyloop_timeout) {
> > + for (i = 0; i < hdev->nvqs; ++i) {
> > + r = vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index
> > + i,
> > + busyloop_timeout);
> > + if (r < 0) {
> > + goto fail_busyloop;
> > + }
> > + }
> > + }
> > +
> > hdev->features = features;
> >
> > hdev->memory_listener = (MemoryListener) {
> > @@ -1077,6 +1110,11 @@ int vhost_dev_init(struct vhost_dev *hdev, void
> > *opaque,
> > hdev->memory_changed = false;
> > memory_listener_register(&hdev->memory_listener,
> > &address_space_memory);
> > return 0;
> > +fail_busyloop:
> > + while (--i >= 0) {
> > + vhost_virtqueue_set_busyloop_timeout(hdev, hdev->vq_index + i, 0);
> > + }
> > + i = hdev->nvqs;
> > fail_vq:
> > while (--i >= 0) {
> > vhost_virtqueue_cleanup(hdev->vqs + i);
> > diff --git a/include/hw/virtio/vhost-backend.h
> > b/include/hw/virtio/vhost-backend.h
> > index 95fcc96..84e1cb7 100644
> > --- a/include/hw/virtio/vhost-backend.h
> > +++ b/include/hw/virtio/vhost-backend.h
> > @@ -57,6 +57,8 @@ typedef int (*vhost_set_vring_kick_op)(struct vhost_dev
> > *dev,
> > struct vhost_vring_file *file);
> > typedef int (*vhost_set_vring_call_op)(struct vhost_dev *dev,
> > struct vhost_vring_file *file);
> > +typedef int (*vhost_set_vring_busyloop_timeout_op)(struct vhost_dev *dev,
> > + struct
> > vhost_vring_state *r);
> > typedef int (*vhost_set_features_op)(struct vhost_dev *dev,
> > uint64_t features);
> > typedef int (*vhost_get_features_op)(struct vhost_dev *dev,
> > @@ -91,6 +93,7 @@ typedef struct VhostOps {
> > vhost_get_vring_base_op vhost_get_vring_base;
> > vhost_set_vring_kick_op vhost_set_vring_kick;
> > vhost_set_vring_call_op vhost_set_vring_call;
> > + vhost_set_vring_busyloop_timeout_op vhost_set_vring_busyloop_timeout;
> > vhost_set_features_op vhost_set_features;
> > vhost_get_features_op vhost_get_features;
> > vhost_set_owner_op vhost_set_owner;
> > diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> > index b60d758..2106ed8 100644
> > --- a/include/hw/virtio/vhost.h
> > +++ b/include/hw/virtio/vhost.h
> > @@ -64,7 +64,8 @@ struct vhost_dev {
> > };
> >
> > int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
> > - VhostBackendType backend_type);
> > + VhostBackendType backend_type,
> > + uint32_t busyloop_timeout);
> > void vhost_dev_cleanup(struct vhost_dev *hdev);
> > int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev);
> > void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev);
> > diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
> > index 3389b41..8354b98 100644
> > --- a/include/net/vhost_net.h
> > +++ b/include/net/vhost_net.h
> > @@ -10,6 +10,7 @@ typedef struct vhost_net VHostNetState;
> > typedef struct VhostNetOptions {
> > VhostBackendType backend_type;
> > NetClientState *net_backend;
> > + uint32_t busyloop_timeout;
> > void *opaque;
> > } VhostNetOptions;
> >
> > diff --git a/net/tap.c b/net/tap.c
> > index 740e8a2..7e28102 100644
> > --- a/net/tap.c
> > +++ b/net/tap.c
> > @@ -663,6 +663,11 @@ static void net_init_tap_one(const NetdevTapOptions
> > *tap, NetClientState *peer,
> >
> > options.backend_type = VHOST_BACKEND_TYPE_KERNEL;
> > options.net_backend = &s->nc;
> > + if (tap->has_vhost_poll_us) {
> > + options.busyloop_timeout = tap->vhost_poll_us;
> > + } else {
> > + options.busyloop_timeout = 0;
> > + }
> >
> > if (vhostfdname) {
> > vhostfd = monitor_fd_param(cur_mon, vhostfdname, &err);
> > @@ -686,8 +691,9 @@ static void net_init_tap_one(const NetdevTapOptions
> > *tap, NetClientState *peer,
> > "vhost-net requested but could not be initialized");
> > return;
> > }
> > - } else if (vhostfdname) {
> > - error_setg(errp, "vhostfd= is not valid without vhost");
> > + } else if (vhostfdname || tap->has_vhost_poll_us) {
> > + error_setg(errp, "vhostfd(s)= or vhost_poll_us= is not valid"
> > + " without vhost");
> > }
> > }
> >
> > diff --git a/net/vhost-user.c b/net/vhost-user.c
> > index 1b9e73a..b200182 100644
> > --- a/net/vhost-user.c
> > +++ b/net/vhost-user.c
> > @@ -80,6 +80,7 @@ static int vhost_user_start(int queues, NetClientState
> > *ncs[])
> >
> > options.net_backend = ncs[i];
> > options.opaque = s->chr;
> > + options.busyloop_timeout = 0;
> > s->vhost_net = vhost_net_init(&options);
> > if (!s->vhost_net) {
> > error_report("failed to init vhost_net for queue %d", i);
> > diff --git a/qapi-schema.json b/qapi-schema.json
> > index 54634c4..8afdedf 100644
> > --- a/qapi-schema.json
> > +++ b/qapi-schema.json
> > @@ -2531,6 +2531,9 @@
> > #
> > # @queues: #optional number of queues to be created for multiqueue capable
> > tap
> > #
> > +# @vhost-poll-us: #optional maximum number of microseconds that could
> > +# be spent on busy polling for vhost net (since 2.7)
> > +#
> > # Since 1.2
> > ##
> > { 'struct': 'NetdevTapOptions',
> > @@ -2547,7 +2550,8 @@
> > '*vhostfd': 'str',
> > '*vhostfds': 'str',
> > '*vhostforce': 'bool',
> > - '*queues': 'uint32'} }
> > + '*queues': 'uint32',
> > + '*vhost-poll-us': 'uint32'} }
> >
> > ##
> > # @NetdevSocketOptions
> > diff --git a/qemu-options.hx b/qemu-options.hx
> > index 587de8f..22ddb82 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -1569,6 +1569,7 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
> > "-netdev
> > tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n"
> > "
> > [,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n"
> > "
> > [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n"
> > + " [,vhost-poll-us=n]\n"
> > " configure a host TAP network backend with ID 'str'\n"
> > " use network scripts 'file' (default="
> > DEFAULT_NETWORK_SCRIPT ")\n"
> > " to configure it and 'dfile' (default="
> > DEFAULT_NETWORK_DOWN_SCRIPT ")\n"
> > @@ -1588,6 +1589,8 @@ DEF("netdev", HAS_ARG, QEMU_OPTION_netdev,
> > " use 'vhostfd=h' to connect to an already opened vhost
> > net device\n"
> > " use 'vhostfds=x:y:...:z to connect to multiple
> > already opened vhost net devices\n"
> > " use 'queues=n' to specify the number of queues to be
> > created for multiqueue TAP\n"
> > + " use 'vhost-poll-us=n' to speciy the maximum number of
> > microseconds that could be\n"
> > + " spent on busy polling for vhost net\n"
> > "-netdev bridge,id=str[,br=bridge][,helper=helper]\n"
> > " configure a host TAP network backend with ID 'str'
> > that is\n"
> > " connected to a bridge (default="
> > DEFAULT_BRIDGE_INTERFACE ")\n"
>
