> From: Eli Cohen <elic@xxxxxxxxxx>
> Sent: Thursday, November 25, 2021 1:37 PM
>
> On Thu, Nov 25, 2021 at 07:34:21AM +0200, Parav Pandit wrote:
> >
> >
> > > From: Eli Cohen <elic@xxxxxxxxxx>
> > > Sent: Wednesday, November 24, 2021 10:26 PM
> > >
> > > Add support for querying virtqueue statistics. Supported statistics are:
> > >
> > > received_desc - number of descriptors received for the virtqueue
> > > completed_desc - number of descriptors completed for the virtqueue
> > >
> > > A descriptors using indirect buffers is still counted as 1. In
> > > addition, N chained descriptors are counted correctly N times as one would
> expect.
> > >
> > > A new callback was added to vdpa_config_ops which provides the means
> > > for the vdpa driver to return statistics results.
> > >
> > > The interface allows for reading all the supported virtqueues,
> > > including the control virtqueue if it exists, by returning the next queue
> index to query.
> > >
> > > Examples:
> > > 1. Read statisitics for the virtqueue at index 1 $ vdpa dev vstats
> > > show vdpa-a qidx 0
> > > vdpa-a:
> > > qidx 0 rx received_desc 256 completed_desc 9
> > >
> > > 2. Read statisitics for all the virtqueues $ vdpa dev vstats show
> > > vdpa-a
> > > vdpa-a:
> > > qidx 0 rx received_desc 256 completed_desc 9 qidx 1 tx received_desc
> > > 21 completed_desc 21 qidx 2 ctrl received_desc 0 completed_desc 0
> > >
> > > Signed-off-by: Eli Cohen <elic@xxxxxxxxxx>
> > > ---
> > > v0 -> v1:
> > > Emphasize that we're dealing with vendor specific counters.
> > > Terminate query loop on error
> > >
> > > drivers/vdpa/vdpa.c | 144
> ++++++++++++++++++++++++++++++++++++++
> > > include/linux/vdpa.h | 10 +++
> > > include/uapi/linux/vdpa.h | 9 +++
> > > 3 files changed, 163 insertions(+)
> > >
> > > diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c index
> > > 7332a74a4b00..da658c80ff2a 100644
> > > --- a/drivers/vdpa/vdpa.c
> > > +++ b/drivers/vdpa/vdpa.c
> > > @@ -781,6 +781,90 @@ vdpa_dev_config_fill(struct vdpa_device *vdev,
> > > struct sk_buff *msg, u32 portid,
> > > return err;
> > > }
> > >
> > > +static int vdpa_fill_stats_rec(struct vdpa_device *vdev, struct
> > > +sk_buff *msg, u16 *index) {
> > > + struct vdpa_vq_stats stats;
> > Better to name it vdpa_vq_vstats as this is reflecting vendor stats.
> ok
> > > +
> > > +static int vdpa_dev_net_stats_fill(struct vdpa_device *vdev, struct
> > vdpa_dev_net_vstats_fill
> ok
> >
> > > +sk_buff *msg, u16 index) {
> > > + int err;
> > > +
> > > + if (!vdev->config->get_vq_stats)
> > > + return -EOPNOTSUPP;
> > > +
> > > + if (index != VDPA_INVAL_QUEUE_INDEX) {
> > > + err = vdpa_fill_stats_rec(vdev, msg, &index);
> > > + if (err)
> > > + return err;
> > > + } else {
> > > + index = 0;
> > > + do {
> > > + err = vdpa_fill_stats_rec(vdev, msg, &index);
> > > + if (err)
> > > + return err;
> > > + } while (index != VDPA_INVAL_QUEUE_INDEX);
> > > + }
> > > +
> > > + return 0;
> > > +}
> > > +
> > > +static int vdpa_dev_stats_fill(struct vdpa_device *vdev, struct
> > > +sk_buff *msg,
> > > u32 portid,
> > > + u32 seq, int flags, u16 index) {
> > > + u32 device_id;
> > > + void *hdr;
> > > + int err;
> > > +
> > > + hdr = genlmsg_put(msg, portid, seq, &vdpa_nl_family, flags,
> > > + VDPA_CMD_DEV_VSTATS_GET);
> > > + if (!hdr)
> > > + return -EMSGSIZE;
> > > +
> > > + if (nla_put_string(msg, VDPA_ATTR_DEV_NAME, dev_name(&vdev-
> > > >dev))) {
> > > + err = -EMSGSIZE;
> > > + goto undo_msg;
> > > + }
> > > +
> > > + device_id = vdev->config->get_device_id(vdev);
> > > + if (nla_put_u32(msg, VDPA_ATTR_DEV_ID, device_id)) {
> > > + err = -EMSGSIZE;
> > > + goto undo_msg;
> > > + }
> > > +
> > > + err = vdpa_dev_net_stats_fill(vdev, msg, index);
> > > +
> > > + genlmsg_end(msg, hdr);
> > > +
> > > + return err;
> > > +
> > > +undo_msg:
> > > + genlmsg_cancel(msg, hdr);
> > > + return err;
> > > +}
> > > +
> > > static int vdpa_nl_cmd_dev_config_get_doit(struct sk_buff *skb,
> > > struct genl_info *info) {
> > > struct vdpa_device *vdev;
> > > @@ -862,6 +946,59 @@ vdpa_nl_cmd_dev_config_get_dumpit(struct
> > > sk_buff *msg, struct netlink_callback *
> > > return msg->len;
> > > }
> > >
> > > +static int vdpa_nl_cmd_dev_stats_get_doit(struct sk_buff *skb,
> > > + struct genl_info *info)
> > > +{
> > > + struct vdpa_device *vdev;
> > > + struct sk_buff *msg;
> > > + const char *devname;
> > > + struct device *dev;
> > > + u16 index = -1;
> > > + int err;
> > > +
> > > + if (!info->attrs[VDPA_ATTR_DEV_NAME])
> > > + return -EINVAL;
> > > +
> > > + if (info->attrs[VDPA_ATTR_DEV_QUEUE_INDEX])
> > > + index = nla_get_u16(info-
> > > >attrs[VDPA_ATTR_DEV_QUEUE_INDEX]);
> > > +
> > > + devname = nla_data(info->attrs[VDPA_ATTR_DEV_NAME]);
> > > + msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
> > > + if (!msg)
> > > + return -ENOMEM;
> > > +
> > > + mutex_lock(&vdpa_dev_mutex);
> > > + dev = bus_find_device(&vdpa_bus, NULL, devname,
> > > vdpa_name_match);
> > > + if (!dev) {
> > > + NL_SET_ERR_MSG_MOD(info->extack, "device not found");
> > > + err = -ENODEV;
> > > + goto dev_err;
> > > + }
> > > + vdev = container_of(dev, struct vdpa_device, dev);
> > > + if (!vdev->mdev) {
> > > + NL_SET_ERR_MSG_MOD(info->extack, "unmanaged vdpa
> > > device");
> > > + err = -EINVAL;
> > > + goto mdev_err;
> > > + }
> > > + err = vdpa_dev_stats_fill(vdev, msg, info->snd_portid,
> > > +info->snd_seq,
> > > 0, index);
> > We should be really dumping all queue stats of the device in the dumpit()
> routine.
> > But there are some limitation from netlink core to enable it.
> > Given that, I prefer we limit current vstats dump to single q whose index is
> specified by the user.
>
> I can live with this. If no one objects, we can simplify the code to return stats
> for a single VQ.
Yeah.
> In that case we can also adopt Jason's suggestion to let the parent driver fill it
> with pairs of field/data for each vendor.
>
Yes, for now, there is single vendor reporting it and stats are generic enough with only two fields.
So it is not really a burden. We should wait for other drivers to grow and actually diverge from current defined stats.
At that point it will be more natural to move in specific drivers.
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