Re: [PATCH net-next V2 3/4] virtio_net: support per queue interrupt coalesce command

[Gavin Li <gavinl@xxxxxxxxxx>]

On 7/18/2023 11:29 AM, Heng Qi wrote:
> 在 2023/7/17 下午10:30, Gavin Li 写道:
> > Add interrupt_coalesce config in send_queue and receive_queue to cache 
> > user
> > config.
> >
> > Send per virtqueue interrupt moderation config to underline device in 
> > order
> > to have more efficient interrupt moderation and cpu utilization of guest
> > VM.
> >
> > Signed-off-by: Gavin Li <gavinl@xxxxxxxxxx>
> > Reviewed-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
> > Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>
> > Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> > ---
> >   drivers/net/virtio_net.c        | 123 ++++++++++++++++++++++++++++----
> >   include/uapi/linux/virtio_net.h |  14 ++++
> >   2 files changed, 125 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> > index 802ed21453f5..1566c7de9436 100644
> > --- a/drivers/net/virtio_net.c
> > +++ b/drivers/net/virtio_net.c
> > @@ -144,6 +144,8 @@ struct send_queue {
> >       struct virtnet_sq_stats stats;
> > +    struct virtnet_interrupt_coalesce intr_coal;
> > +
> >       struct napi_struct napi;
> >       /* Record whether sq is in reset state. */
> > @@ -161,6 +163,8 @@ struct receive_queue {
> >       struct virtnet_rq_stats stats;
> > +    struct virtnet_interrupt_coalesce intr_coal;
> > +
> >       /* Chain pages by the private ptr. */
> >       struct page *pages;
> > @@ -3078,6 +3082,59 @@ static int virtnet_send_notf_coal_cmds(struct 
> > virtnet_info *vi,
> >       return 0;
> >   }
> > +static int virtnet_send_ctrl_coal_vq_cmd(struct virtnet_info *vi,
> > +                     u16 vqn, u32 max_usecs, u32 max_packets)
> > +{
> > +    struct virtio_net_ctrl_coal_vq *coal_vq;
> > +    struct scatterlist sgs;
> > +
> > +    coal_vq = kzalloc(sizeof(*coal_vq), GFP_KERNEL);
>
> I think this should go in the structure control_buf, which serves two 
> purposes, and that's on the heap in init_vqs():
> 1. We can have the same form as other control types, such as 
> virtio_net_ctrl_coal_{tx, rx};
> 2. Avoid using heap memory here to cause the following memory leaks
ACK
> > +    if (!coal_vq)
> > +        return -ENOMEM;
> > +    coal_vq->vqn = cpu_to_le16(vqn);
> > +    coal_vq->coal.max_usecs = cpu_to_le32(max_usecs);
> > +    coal_vq->coal.max_packets = cpu_to_le32(max_packets);
> > +    sg_init_one(&sgs, coal_vq, sizeof(*coal_vq));
> > +
> > +    if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
> > +                  VIRTIO_NET_CTRL_NOTF_COAL_VQ_SET,
> > +                  &sgs))
> > +        return -EINVAL;
>
> If this fails, we should free coal_vq, so pls move coal_vq into 
> control_buf.
>
> Thanks.
> ACK
> > +
> > +    return 0;
> > +}
> > +
> > +static int virtnet_send_notf_coal_vq_cmds(struct virtnet_info *vi,
> > +                      struct ethtool_coalesce *ec,
> > +                      u16 queue)
> > +{
> > +    int err;
> > +
> > +    if (ec->rx_coalesce_usecs || ec->rx_max_coalesced_frames) {
> > +        err = virtnet_send_ctrl_coal_vq_cmd(vi, rxq2vq(queue),
> > +                            ec->rx_coalesce_usecs,
> > +                            ec->rx_max_coalesced_frames);
> > +        if (err)
> > +            return err;
> > +        /* Save parameters */
> > +        vi->rq[queue].intr_coal.max_usecs = ec->rx_coalesce_usecs;
> > +        vi->rq[queue].intr_coal.max_packets = 
> > ec->rx_max_coalesced_frames;
> > +    }
> > +
> > +    if (ec->tx_coalesce_usecs || ec->tx_max_coalesced_frames) {
> > +        err = virtnet_send_ctrl_coal_vq_cmd(vi, txq2vq(queue),
> > +                            ec->tx_coalesce_usecs,
> > +                            ec->tx_max_coalesced_frames);
> > +        if (err)
> > +            return err;
> > +        /* Save parameters */
> > +        vi->sq[queue].intr_coal.max_usecs = ec->tx_coalesce_usecs;
> > +        vi->sq[queue].intr_coal.max_packets = 
> > ec->tx_max_coalesced_frames;
> > +    }
> > +
> > +    return 0;
> > +}
> > +
> >   static int virtnet_coal_params_supported(struct ethtool_coalesce *ec)
> >   {
> >       /* usecs coalescing is supported only if VIRTIO_NET_F_NOTF_COAL
> > @@ -3094,23 +3151,39 @@ static int 
> > virtnet_coal_params_supported(struct ethtool_coalesce *ec)
> >   }
> >   static int virtnet_set_coalesce_one(struct net_device *dev,
> > -                    struct ethtool_coalesce *ec)
> > +                    struct ethtool_coalesce *ec,
> > +                    bool per_queue,
> > +                    u32 queue)
> >   {
> >       struct virtnet_info *vi = netdev_priv(dev);
> > -    int ret, i, napi_weight;
> > +    int queue_count = per_queue ? 1 : vi->max_queue_pairs;
> > +    int queue_number = per_queue ? queue : 0;
> >       bool update_napi = false;
> > +    int ret, i, napi_weight;
> > +
> > +    if (queue >= vi->max_queue_pairs)
> > +        return -EINVAL;
> >       /* Can't change NAPI weight if the link is up */
> >       napi_weight = ec->tx_max_coalesced_frames ? NAPI_POLL_WEIGHT : 0;
> > -    if (napi_weight ^ vi->sq[0].napi.weight) {
> > -        if (dev->flags & IFF_UP)
> > -            return -EBUSY;
> > -        else
> > +    for (i = queue_number; i < queue_count; i++) {
> > +        if (napi_weight ^ vi->sq[i].napi.weight) {
> > +            if (dev->flags & IFF_UP)
> > +                return -EBUSY;
> > +
> >               update_napi = true;
> > +            /* All queues that belong to [queue_number, queue_count] 
> > will be
> > +             * updated for the sake of simplicity, which might not be 
> > necessary
> > +             */
> > +            queue_number = i;
> > +            break;
> > +        }
> >       }
> > -    if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL))
> > +    if (!per_queue && virtio_has_feature(vi->vdev, 
> > VIRTIO_NET_F_NOTF_COAL))
> >           ret = virtnet_send_notf_coal_cmds(vi, ec);
> > +    else if (per_queue && virtio_has_feature(vi->vdev, 
> > VIRTIO_NET_F_VQ_NOTF_COAL))
> > +        ret = virtnet_send_notf_coal_vq_cmds(vi, ec, queue);
> >       else
> >           ret = virtnet_coal_params_supported(ec);
> > @@ -3118,7 +3191,7 @@ static int virtnet_set_coalesce_one(struct 
> > net_device *dev,
> >           return ret;
> >       if (update_napi) {
> > -        for (i = 0; i < vi->max_queue_pairs; i++)
> > +        for (i = queue_number; i < queue_count; i++)
> >               vi->sq[i].napi.weight = napi_weight;
> >       }
> > @@ -3130,19 +3203,29 @@ static int virtnet_set_coalesce(struct 
> > net_device *dev,
> >                   struct kernel_ethtool_coalesce *kernel_coal,
> >                   struct netlink_ext_ack *extack)
> >   {
> > -    return virtnet_set_coalesce_one(dev, ec);
> > +    return virtnet_set_coalesce_one(dev, ec, false, 0);
> >   }
> >   static int virtnet_get_coalesce_one(struct net_device *dev,
> > -                    struct ethtool_coalesce *ec)
> > +                    struct ethtool_coalesce *ec,
> > +                    bool per_queue,
> > +                    u32 queue)
> >   {
> >       struct virtnet_info *vi = netdev_priv(dev);
> > -    if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) {
> > +    if (queue >= vi->max_queue_pairs)
> > +        return -EINVAL;
> > +
> > +    if (!per_queue && virtio_has_feature(vi->vdev, 
> > VIRTIO_NET_F_NOTF_COAL)) {
> >           ec->rx_coalesce_usecs = vi->intr_coal_rx.max_usecs;
> >           ec->tx_coalesce_usecs = vi->intr_coal_tx.max_usecs;
> >           ec->tx_max_coalesced_frames = vi->intr_coal_tx.max_packets;
> >           ec->rx_max_coalesced_frames = vi->intr_coal_rx.max_packets;
> > +    } else if (per_queue && virtio_has_feature(vi->vdev, 
> > VIRTIO_NET_F_VQ_NOTF_COAL)) {
> > +        ec->rx_coalesce_usecs = vi->rq[queue].intr_coal.max_usecs;
> > +        ec->tx_coalesce_usecs = vi->sq[queue].intr_coal.max_usecs;
> > +        ec->tx_max_coalesced_frames = 
> > vi->sq[queue].intr_coal.max_packets;
> > +        ec->rx_max_coalesced_frames = 
> > vi->rq[queue].intr_coal.max_packets;
> >       } else {
> >           ec->rx_max_coalesced_frames = 1;
> > @@ -3158,7 +3241,21 @@ static int virtnet_get_coalesce(struct 
> > net_device *dev,
> >                   struct kernel_ethtool_coalesce *kernel_coal,
> >                   struct netlink_ext_ack *extack)
> >   {
> > -    return virtnet_get_coalesce_one(dev, ec);
> > +    return virtnet_get_coalesce_one(dev, ec, false, 0);
> > +}
> > +
> > +static int virtnet_set_per_queue_coalesce(struct net_device *dev,
> > +                      u32 queue,
> > +                      struct ethtool_coalesce *ec)
> > +{
> > +    return virtnet_set_coalesce_one(dev, ec, true, queue);
> > +}
> > +
> > +static int virtnet_get_per_queue_coalesce(struct net_device *dev,
> > +                      u32 queue,
> > +                      struct ethtool_coalesce *ec)
> > +{
> > +    return virtnet_get_coalesce_one(dev, ec, true, queue);
> >   }
> >   static void virtnet_init_settings(struct net_device *dev)
> > @@ -3291,6 +3388,8 @@ static const struct ethtool_ops 
> > virtnet_ethtool_ops = {
> >       .set_link_ksettings = virtnet_set_link_ksettings,
> >       .set_coalesce = virtnet_set_coalesce,
> >       .get_coalesce = virtnet_get_coalesce,
> > +    .set_per_queue_coalesce = virtnet_set_per_queue_coalesce,
> > +    .get_per_queue_coalesce = virtnet_get_per_queue_coalesce,
> >       .get_rxfh_key_size = virtnet_get_rxfh_key_size,
> >       .get_rxfh_indir_size = virtnet_get_rxfh_indir_size,
> >       .get_rxfh = virtnet_get_rxfh,
> > diff --git a/include/uapi/linux/virtio_net.h 
> > b/include/uapi/linux/virtio_net.h
> > index 12c1c9699935..cc65ef0f3c3e 100644
> > --- a/include/uapi/linux/virtio_net.h
> > +++ b/include/uapi/linux/virtio_net.h
> > @@ -56,6 +56,7 @@
> >   #define VIRTIO_NET_F_MQ    22    /* Device supports Receive Flow
> >                        * Steering */
> >   #define VIRTIO_NET_F_CTRL_MAC_ADDR 23    /* Set MAC address */
> > +#define VIRTIO_NET_F_VQ_NOTF_COAL 52    /* Device supports virtqueue 
> > notification coalescing */
> >   #define VIRTIO_NET_F_NOTF_COAL    53    /* Device supports 
> > notifications coalescing */
> >   #define VIRTIO_NET_F_GUEST_USO4    54    /* Guest can handle USOv4 
> > in. */
> >   #define VIRTIO_NET_F_GUEST_USO6    55    /* Guest can handle USOv6 
> > in. */
> > @@ -391,5 +392,18 @@ struct virtio_net_ctrl_coal_rx {
> >   };
> >   #define VIRTIO_NET_CTRL_NOTF_COAL_RX_SET        1
> > +#define VIRTIO_NET_CTRL_NOTF_COAL_VQ_SET        2
> > +#define VIRTIO_NET_CTRL_NOTF_COAL_VQ_GET        3
> > +
> > +struct virtio_net_ctrl_coal {
> > +    __le32 max_packets;
> > +    __le32 max_usecs;
> > +};
> > +
> > +struct  virtio_net_ctrl_coal_vq {
> > +    __le16 vqn;
> > +    __le16 reserved;
> > +    struct virtio_net_ctrl_coal coal;
> > +};
> >   #endif /* _UAPI_LINUX_VIRTIO_NET_H */