Currently, control vq handles commands synchronously,
leading to increased delays for dim commands during multi-queue
VM configuration and directly impacting dim performance.
To address this, we are shifting to asynchronous processing of
ctrlq's dim commands.
Signed-off-by: Heng Qi <hengqi@xxxxxxxxxxxxxxxxx>
---
drivers/net/virtio_net.c | 221 +++++++++++++++++++++++++++++++++++----
1 file changed, 201 insertions(+), 20 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 807724772bcf..bd224e282f9b 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -376,6 +376,12 @@ struct control_buf {
struct completion completion;
};
+struct virtnet_coal_node {
+ struct control_buf ctrl;
+ struct virtio_net_ctrl_coal_vq coal_vqs;
+ struct list_head list;
+};
+
struct virtnet_info {
struct virtio_device *vdev;
struct virtqueue *cvq;
@@ -420,6 +426,12 @@ struct virtnet_info {
/* Lock to protect the control VQ */
struct mutex cvq_lock;
+ /* Work struct for acquisition of cvq processing results. */
+ struct work_struct get_cvq;
+
+ /* OK to queue work getting cvq response? */
+ bool get_cvq_work_enabled;
+
/* Host can handle any s/g split between our header and packet data */
bool any_header_sg;
@@ -464,6 +476,10 @@ struct virtnet_info {
struct virtnet_interrupt_coalesce intr_coal_tx;
struct virtnet_interrupt_coalesce intr_coal_rx;
+ /* Free nodes used for concurrent delivery */
+ struct mutex coal_free_lock;
+ struct list_head coal_free_list;
+
unsigned long guest_offloads;
unsigned long guest_offloads_capable;
@@ -666,11 +682,26 @@ static bool virtqueue_napi_complete(struct napi_struct *napi,
return false;
}
+static void enable_get_cvq_work(struct virtnet_info *vi)
+{
+ rtnl_lock();
+ vi->get_cvq_work_enabled = true;
+ rtnl_unlock();
+}
+
+static void disable_get_cvq_work(struct virtnet_info *vi)
+{
+ rtnl_lock();
+ vi->get_cvq_work_enabled = false;
+ rtnl_unlock();
+}
+
static void virtnet_cvq_done(struct virtqueue *cvq)
{
struct virtnet_info *vi = cvq->vdev->priv;
- complete(&vi->ctrl->completion);
+ virtqueue_disable_cb(cvq);
+ schedule_work(&vi->get_cvq);
}
static void skb_xmit_done(struct virtqueue *vq)
@@ -2730,6 +2761,7 @@ static bool virtnet_add_command_reply(struct virtnet_info *vi,
return false;
}
+ mutex_unlock(&vi->cvq_lock);
return true;
}
@@ -2740,10 +2772,8 @@ static bool virtnet_wait_command_response(struct virtnet_info *vi,
bool ok;
wait_for_completion(&ctrl->completion);
- virtqueue_get_buf(vi->cvq, &tmp);
ok = ctrl->status == VIRTIO_NET_OK;
- mutex_unlock(&vi->cvq_lock);
return ok;
}
@@ -2772,6 +2802,89 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
return virtnet_send_command_reply(vi, class, cmd, vi->ctrl, out, NULL);
}
+static bool virtnet_process_dim_cmd(struct virtnet_info *vi,
+ struct virtnet_coal_node *node)
+{
+ u16 qnum = le16_to_cpu(node->coal_vqs.vqn) / 2;
+ bool ret;
+
+ ret = virtnet_wait_command_response(vi, &node->ctrl);
+ if (ret) {
+ mutex_lock(&vi->rq[qnum].dim_lock);
+ vi->rq[qnum].intr_coal.max_usecs =
+ le32_to_cpu(node->coal_vqs.coal.max_usecs);
+ vi->rq[qnum].intr_coal.max_packets =
+ le32_to_cpu(node->coal_vqs.coal.max_packets);
+ mutex_unlock(&vi->rq[qnum].dim_lock);
+ }
+
+ vi->rq[qnum].dim.state = DIM_START_MEASURE;
+
+ mutex_lock(&vi->coal_free_lock);
+ list_add(&node->list, &vi->coal_free_list);
+ mutex_unlock(&vi->coal_free_lock);
+ return ret;
+}
+
+static bool virtnet_add_dim_command(struct virtnet_info *vi,
+ struct receive_queue *rq,
+ struct dim_cq_moder update_moder,
+ struct virtnet_coal_node **avail_coal)
+{
+ struct virtnet_coal_node *node;
+ struct scatterlist sg;
+ bool ret;
+
+ mutex_lock(&vi->coal_free_lock);
+ if (list_empty(&vi->coal_free_list)) {
+ mutex_unlock(&vi->coal_free_lock);
+ return false;
+ }
+
+ node = list_first_entry(&vi->coal_free_list,
+ struct virtnet_coal_node, list);
+ node->coal_vqs.vqn = cpu_to_le16(rxq2vq(rq - vi->rq));
+ node->coal_vqs.coal.max_usecs = cpu_to_le32(update_moder.usec);
+ node->coal_vqs.coal.max_packets = cpu_to_le32(update_moder.pkts);
+
+ sg_init_one(&sg, &node->coal_vqs, sizeof(node->coal_vqs));
+ ret = virtnet_add_command_reply(vi, VIRTIO_NET_CTRL_NOTF_COAL,
+ VIRTIO_NET_CTRL_NOTF_COAL_VQ_SET,
+ &node->ctrl, &sg, NULL);
+ if (!ret) {
+ dev_warn(&vi->dev->dev,
+ "Failed to change coalescing params.\n");
+ mutex_unlock(&vi->coal_free_lock);
+ return ret;
+ }
+
+ *avail_coal = node;
+ list_del(&node->list);
+ mutex_unlock(&vi->coal_free_lock);
+
+ return true;
+}
+
+static void virtnet_get_cvq_work(struct work_struct *work)
+{
+ struct virtnet_info *vi =
+ container_of(work, struct virtnet_info, get_cvq);
+ unsigned int tmp;
+ int opaque;
+ void *res;
+
+again:
+ mutex_lock(&vi->cvq_lock);
+ while ((res = virtqueue_get_buf(vi->cvq, &tmp)) != NULL)
+ complete((struct completion *)res);
+ mutex_unlock(&vi->cvq_lock);
+
+ opaque = virtqueue_enable_cb_prepare(vi->cvq);
+ if (unlikely(virtqueue_poll(vi->cvq, opaque))) {
+ virtqueue_disable_cb(vi->cvq);
+ goto again;
+ }
+}
static int virtnet_set_mac_address(struct net_device *dev, void *p)
{
struct virtnet_info *vi = netdev_priv(dev);
@@ -4419,35 +4532,54 @@ static int virtnet_send_notf_coal_vq_cmds(struct virtnet_info *vi,
return 0;
}
+static void virtnet_wait_space(struct virtnet_info *vi)
+{
+ bool no_coal_free = true;
+
+ while (READ_ONCE(vi->cvq->num_free) < 3)
+ usleep_range(1000, 2000);
+
+ while (no_coal_free) {
+ mutex_lock(&vi->coal_free_lock);
+ if (!list_empty(&vi->coal_free_list))
+ no_coal_free = false;
+ mutex_unlock(&vi->coal_free_lock);
+ if (no_coal_free)
+ usleep_range(1000, 2000);
+ }
+}
+
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 virtnet_coal_node *avail_coal;
struct dim_cq_moder update_moder;
- int qnum, err;
- qnum = rq - vi->rq;
+ update_moder = net_dim_get_rx_moderation(dim->mode, dim->profile_ix);
mutex_lock(&rq->dim_lock);
- if (!rq->dim_enabled)
- goto out;
-
- update_moder = net_dim_get_rx_moderation(dim->mode, dim->profile_ix);
- if (update_moder.usec != rq->intr_coal.max_usecs ||
- update_moder.pkts != rq->intr_coal.max_packets) {
- 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, qnum);
+ if (!rq->dim_enabled ||
+ (update_moder.usec == rq->intr_coal.max_usecs &&
+ update_moder.pkts == rq->intr_coal.max_packets)) {
+ rq->dim.state = DIM_START_MEASURE;
+ mutex_unlock(&rq->dim_lock);
+ return;
}
-out:
- dim->state = DIM_START_MEASURE;
mutex_unlock(&rq->dim_lock);
+
+again:
+ virtnet_wait_space(vi);
+
+ if (!virtnet_add_dim_command(vi, rq, update_moder, &avail_coal)) {
+ if (virtqueue_is_broken(vi->cvq))
+ return;
+ goto again;
+ }
+
+ virtnet_process_dim_cmd(vi, avail_coal);
}
static int virtnet_coal_params_supported(struct ethtool_coalesce *ec)
@@ -4860,6 +4992,8 @@ static void virtnet_freeze_down(struct virtio_device *vdev)
flush_work(&vi->config_work);
disable_rx_mode_work(vi);
flush_work(&vi->rx_mode_work);
+ disable_get_cvq_work(vi);
+ flush_work(&vi->get_cvq);
netif_tx_lock_bh(vi->dev);
netif_device_detach(vi->dev);
@@ -4883,6 +5017,7 @@ static int virtnet_restore_up(struct virtio_device *vdev)
enable_delayed_refill(vi);
enable_rx_mode_work(vi);
+ enable_get_cvq_work(vi);
if (netif_running(vi->dev)) {
err = virtnet_open(vi->dev);
@@ -5633,6 +5768,43 @@ static const struct xdp_metadata_ops virtnet_xdp_metadata_ops = {
.xmo_rx_hash = virtnet_xdp_rx_hash,
};
+static void virtnet_del_coal_free_list(struct virtnet_info *vi)
+{
+ struct virtnet_coal_node *coal_node, *tmp;
+
+ list_for_each_entry_safe(coal_node, tmp, &vi->coal_free_list, list) {
+ list_del(&coal_node->list);
+ kfree(coal_node);
+ }
+}
+
+static int virtnet_init_coal_list(struct virtnet_info *vi)
+{
+ struct virtnet_coal_node *coal_node;
+ int batch_dim_nums;
+ int i;
+
+ INIT_LIST_HEAD(&vi->coal_free_list);
+ mutex_init(&vi->coal_free_lock);
+
+ if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_VQ_NOTF_COAL))
+ return 0;
+
+ batch_dim_nums = min((unsigned int)vi->max_queue_pairs,
+ virtqueue_get_vring_size(vi->cvq) / 3);
+ for (i = 0; i < batch_dim_nums; i++) {
+ coal_node = kzalloc(sizeof(*coal_node), GFP_KERNEL);
+ if (!coal_node) {
+ virtnet_del_coal_free_list(vi);
+ return -ENOMEM;
+ }
+ init_completion(&coal_node->ctrl.completion);
+ list_add(&coal_node->list, &vi->coal_free_list);
+ }
+
+ return 0;
+}
+
static int virtnet_probe(struct virtio_device *vdev)
{
int i, err = -ENOMEM;
@@ -5818,6 +5990,9 @@ static int virtnet_probe(struct virtio_device *vdev)
if (err)
goto free;
+ if (virtnet_init_coal_list(vi))
+ goto free;
+
if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_NOTF_COAL)) {
vi->intr_coal_rx.max_usecs = 0;
vi->intr_coal_tx.max_usecs = 0;
@@ -5859,7 +6034,9 @@ static int virtnet_probe(struct virtio_device *vdev)
if (vi->has_rss || vi->has_rss_hash_report)
virtnet_init_default_rss(vi);
+ INIT_WORK(&vi->get_cvq, virtnet_get_cvq_work);
init_completion(&vi->ctrl->completion);
+ enable_get_cvq_work(vi);
enable_rx_mode_work(vi);
/* serialize netdev register + virtio_device_ready() with ndo_open() */
@@ -5988,11 +6165,15 @@ static void virtnet_remove(struct virtio_device *vdev)
flush_work(&vi->config_work);
disable_rx_mode_work(vi);
flush_work(&vi->rx_mode_work);
+ disable_get_cvq_work(vi);
+ flush_work(&vi->get_cvq);
unregister_netdev(vi->dev);
net_failover_destroy(vi->failover);
+ virtnet_del_coal_free_list(vi);
+
remove_vq_common(vi);
free_netdev(vi->dev);
--
2.32.0.3.g01195cf9f
