By comparing the traffic information in the complete napi processes,
let the virtio-net driver automatically adjust the coalescing
moderation parameters of each receive queue.

Signed-off-by: Heng Qi <redacted>
---
 drivers/net/virtio_net.c | 147 +++++++++++++++++++++++++++++++++------
 1 file changed, 126 insertions(+), 21 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index caef78bb3963..6ad2890a7909 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c

@@ -19,6 +19,7 @@
 #include <linux/average.h>
 #include <linux/filter.h>
 #include <linux/kernel.h>
+#include <linux/dim.h>
 #include <net/route.h>
 #include <net/xdp.h>
 #include <net/net_failover.h>

@@ -172,6 +173,17 @@ struct receive_queue {

        struct virtnet_rq_stats stats;

+       /* The number of rx notifications */
+       u16 calls;
+
+       /* Is dynamic interrupt moderation enabled? */
+       bool dim_enabled;
+
+       /* Dynamic Interrupt Moderation */
+       struct dim dim;
+
+       u32 packets_in_napi;
+
        struct virtnet_interrupt_coalesce intr_coal;

        /* Chain pages by the private ptr. */

@@ -305,6 +317,9 @@ struct virtnet_info {
        u8 duplex;
        u32 speed;

+       /* Is rx dynamic interrupt moderation enabled? */
+       bool rx_dim_enabled;
+
        /* Interrupt coalescing settings */
        struct virtnet_interrupt_coalesce intr_coal_tx;
        struct virtnet_interrupt_coalesce intr_coal_rx;

@@ -2001,6 +2016,7 @@ static void skb_recv_done(struct virtqueue *rvq)
        struct virtnet_info *vi = rvq->vdev->priv;
        struct receive_queue *rq = &vi->rq[vq2rxq(rvq)];

+       rq->calls++;
        virtqueue_napi_schedule(&rq->napi, rvq);
 }

@@ -2138,6 +2154,25 @@ static void virtnet_poll_cleantx(struct receive_queue *rq)
        }
 }

+static void virtnet_rx_dim_work(struct work_struct *work);
+
+static void virtnet_rx_dim_update(struct virtnet_info *vi, struct receive_queue *rq)
+{
+       struct virtnet_rq_stats *stats = &rq->stats;
+       struct dim_sample cur_sample = {};
+
+       if (!rq->packets_in_napi)
+               return;
+
+       u64_stats_update_begin(&rq->stats.syncp);
+       dim_update_sample(rq->calls, stats->packets,
+                         stats->bytes, &cur_sample);
+       u64_stats_update_end(&rq->stats.syncp);
+
+       net_dim(&rq->dim, cur_sample);
+       rq->packets_in_napi = 0;
+}
+
 static int virtnet_poll(struct napi_struct *napi, int budget)
 {
        struct receive_queue *rq =

@@ -2146,17 +2181,22 @@ static int virtnet_poll(struct napi_struct *napi, int budget)
        struct send_queue *sq;
        unsigned int received;
        unsigned int xdp_xmit = 0;
+       bool napi_complete;

        virtnet_poll_cleantx(rq);

        received = virtnet_receive(rq, budget, &xdp_xmit);
+       rq->packets_in_napi += received;

        if (xdp_xmit & VIRTIO_XDP_REDIR)
                xdp_do_flush();

        /* Out of packets? */
-       if (received < budget)
-               virtqueue_napi_complete(napi, rq->vq, received);
+       if (received < budget) {
+               napi_complete = virtqueue_napi_complete(napi, rq->vq, received);
+               if (napi_complete && rq->dim_enabled)
+                       virtnet_rx_dim_update(vi, rq);
+       }

        if (xdp_xmit & VIRTIO_XDP_TX) {
                sq = virtnet_xdp_get_sq(vi);

@@ -2176,6 +2216,7 @@ static void virtnet_disable_queue_pair(struct virtnet_info *vi, int qp_index)
        virtnet_napi_tx_disable(&vi->sq[qp_index].napi);
        napi_disable(&vi->rq[qp_index].napi);
        xdp_rxq_info_unreg(&vi->rq[qp_index].xdp_rxq);
+       cancel_work_sync(&vi->rq[qp_index].dim.work);
 }

 static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)

@@ -2193,6 +2234,9 @@ static int virtnet_enable_queue_pair(struct virtnet_info *vi, int qp_index)
        if (err < 0)
                goto err_xdp_reg_mem_model;

+       INIT_WORK(&vi->rq[qp_index].dim.work, virtnet_rx_dim_work);
+       vi->rq[qp_index].dim.mode = DIM_CQ_PERIOD_MODE_START_FROM_EQE;
+
        virtnet_napi_enable(vi->rq[qp_index].vq, &vi->rq[qp_index].napi);
        virtnet_napi_tx_enable(vi, vi->sq[qp_index].vq, &vi->sq[qp_index].napi);

@@ -3335,23 +3379,42 @@ static int virtnet_send_tx_notf_coal_cmds(struct virtnet_info *vi,
 static int virtnet_send_rx_notf_coal_cmds(struct virtnet_info *vi,
                                          struct ethtool_coalesce *ec)
 {
+       bool rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce;
        struct scatterlist sgs_rx;
+       int i;

-       vi->ctrl->coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs);
-       vi->ctrl->coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames);
-       sg_init_one(&sgs_rx, &vi->ctrl->coal_rx, sizeof(vi->ctrl->coal_rx));
-
-       if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
-                                 VIRTIO_NET_CTRL_NOTF_COAL_RX_SET,
-                                 &sgs_rx))
+       if (rx_ctrl_dim_on && (ec->rx_coalesce_usecs != vi->intr_coal_rx.max_usecs ||
+                              ec->rx_max_coalesced_frames != vi->intr_coal_rx.max_packets))

                return -EINVAL;

-       /* Save parameters */
-       vi->intr_coal_rx.max_usecs = ec->rx_coalesce_usecs;
-       vi->intr_coal_rx.max_packets = ec->rx_max_coalesced_frames;
-       for (i = 0; i < vi->max_queue_pairs; i++) {
-               vi->rq[i].intr_coal.max_usecs = ec->rx_coalesce_usecs;
-               vi->rq[i].intr_coal.max_packets = ec->rx_max_coalesced_frames;
+       if (rx_ctrl_dim_on) {
+               if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL)) {
+                       vi->rx_dim_enabled = true;
+                       for (i = 0; i < vi->max_queue_pairs; i++)
+                               vi->rq[i].dim_enabled = true;
+               } else {
+                       return -EOPNOTSUPP;
+               }
+       } else {
+               vi->rx_dim_enabled = false;
+               for (i = 0; i < vi->max_queue_pairs; i++)
+                       vi->rq[i].dim_enabled = false;
+
+               vi->ctrl->coal_rx.rx_usecs = cpu_to_le32(ec->rx_coalesce_usecs);
+               vi->ctrl->coal_rx.rx_max_packets = cpu_to_le32(ec->rx_max_coalesced_frames);
+               sg_init_one(&sgs_rx, &vi->ctrl->coal_rx, sizeof(vi->ctrl->coal_rx));
+
+               if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_NOTF_COAL,
+                                         VIRTIO_NET_CTRL_NOTF_COAL_RX_SET,
+                                         &sgs_rx))
+                       return -EINVAL;
+
+               vi->intr_coal_rx.max_usecs = ec->rx_coalesce_usecs;
+               vi->intr_coal_rx.max_packets = ec->rx_max_coalesced_frames;
+               for (i = 0; i < vi->max_queue_pairs; i++) {
+                       vi->rq[i].intr_coal.max_usecs = ec->rx_coalesce_usecs;
+                       vi->rq[i].intr_coal.max_packets = ec->rx_max_coalesced_frames;
+               }
        }

        return 0;

@@ -3377,13 +3440,27 @@ static int virtnet_send_notf_coal_vq_cmds(struct virtnet_info *vi,
                                          struct ethtool_coalesce *ec,
                                          u16 queue)
 {
+       bool rx_ctrl_dim_on;
+       u32 max_usecs, max_packets;
        int err;

-       err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, queue,
-                                              ec->rx_coalesce_usecs,
-                                              ec->rx_max_coalesced_frames);
-       if (err)
-               return err;
+       rx_ctrl_dim_on = !!ec->use_adaptive_rx_coalesce;
+       max_usecs = vi->rq[queue].intr_coal.max_usecs;
+       max_packets = vi->rq[queue].intr_coal.max_packets;
+       if (rx_ctrl_dim_on && (ec->rx_coalesce_usecs != max_usecs ||
+                              ec->rx_max_coalesced_frames != max_packets))
+               return -EINVAL;
+
+       if (rx_ctrl_dim_on) {
+               vi->rq[queue].dim_enabled = true;
+       } else {
+               vi->rq[queue].dim_enabled = false;
+               err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, queue,
+                                                      ec->rx_coalesce_usecs,
+                                                      ec->rx_max_coalesced_frames);
+               if (err)
+                       return err;
+       }

        err = virtnet_send_tx_ctrl_coal_vq_cmd(vi, queue,
                                               ec->tx_coalesce_usecs,

@@ -3394,6 +3471,32 @@ static int virtnet_send_notf_coal_vq_cmds(struct virtnet_info *vi,
        return 0;
 }

+static void virtnet_rx_dim_work(struct work_struct *work)
+{
+       struct dim *dim = container_of(work, struct dim, work);
+       struct receive_queue *rq = container_of(dim,
+                       struct receive_queue, dim);
+       struct virtnet_info *vi = rq->vq->vdev->priv;
+       struct net_device *dev = vi->dev;
+       struct dim_cq_moder update_moder;
+       int qnum = rq - vi->rq, err;
+
+       update_moder = net_dim_get_rx_moderation(dim->mode, dim->profile_ix);
+       if (update_moder.usec != vi->rq[qnum].intr_coal.max_usecs ||
+           update_moder.pkts != vi->rq[qnum].intr_coal.max_packets) {

+               rtnl_lock();
+               err = virtnet_send_rx_ctrl_coal_vq_cmd(vi, qnum,
+                                                      update_moder.usec,
+                                                      update_moder.pkts);
+               if (err)
+                       pr_debug("%s: Failed to send dim parameters on rxq%d\n",
+                                dev->name, (int)(rq - vi->rq));
+               rtnl_unlock();
+       }
+
+       dim->state = DIM_START_MEASURE;
+}
+
 static int virtnet_coal_params_supported(struct ethtool_coalesce *ec)
 {
        /* usecs coalescing is supported only if VIRTIO_NET_F_NOTF_COAL

@@ -3475,6 +3578,7 @@ static int virtnet_get_coalesce(struct net_device *dev,
                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;
+               ec->use_adaptive_rx_coalesce = vi->rx_dim_enabled;
        } else {
                ec->rx_max_coalesced_frames = 1;

@@ -3532,6 +3636,7 @@ static int virtnet_get_per_queue_coalesce(struct net_device *dev,
                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;
+               ec->use_adaptive_rx_coalesce = vi->rq[queue].dim_enabled;
        } else {
                ec->rx_max_coalesced_frames = 1;

@@ -3657,7 +3762,7 @@ static int virtnet_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *info)

 static const struct ethtool_ops virtnet_ethtool_ops = {
        .supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES |
-               ETHTOOL_COALESCE_USECS,
+               ETHTOOL_COALESCE_USECS | ETHTOOL_COALESCE_USE_ADAPTIVE_RX,
        .get_drvinfo = virtnet_get_drvinfo,
        .get_link = ethtool_op_get_link,
        .get_ringparam = virtnet_get_ringparam,
--

2.19.1.6.gb485710b