[PATCH RFC v5 net-next 4/6] virtio-net: add basic interrupt coalescing support

Jason Wang
2015-02-09T08:40:54Z

This patch enables the interrupt coalescing setting through ethtool.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/net/virtio_net.c | 67 +++++++++++++++++++++++++++++++++++++++++
include/uapi/linux/virtio_net.h | 12 ++++++++
2 files changed, 79 insertions(+)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index cc5f5de..2b958fb 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -145,6 +145,11 @@ struct virtnet_info {

/* Budget for polling tx completion */
u32 tx_work_limit;
+
+ __u32 rx_coalesce_usecs;
+ __u32 rx_max_coalesced_frames;
+ __u32 tx_coalesce_usecs;
+ __u32 tx_max_coalesced_frames;
};

struct padded_vnet_hdr {
@@ -1404,12 +1409,73 @@ static void virtnet_get_channels(struct net_device *dev,
channels->other_count = 0;
}

+static int virtnet_set_coalesce(struct net_device *dev,
+ struct ethtool_coalesce *ec)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+ struct scatterlist sg;
+ struct virtio_net_ctrl_coalesce c;
+
+ if (!vi->has_cvq ||
+ !virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_COALESCE))
+ return -EOPNOTSUPP;
+ if (vi->rx_coalesce_usecs != ec->rx_coalesce_usecs ||
+ vi->rx_max_coalesced_frames != ec->rx_max_coalesced_frames) {
+ c.coalesce_usecs = ec->rx_coalesce_usecs;
+ c.max_coalesced_frames = ec->rx_max_coalesced_frames;
+ sg_init_one(&sg, &c, sizeof(c));
+ if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE,
+ VIRTIO_NET_CTRL_COALESCE_RX_SET,
+ &sg)) {
+ dev_warn(&dev->dev, "Fail to set rx coalescing\n");
+ return -EINVAL;
+ }
+ vi->rx_coalesce_usecs = ec->rx_coalesce_usecs;
+ vi->rx_max_coalesced_frames = ec->rx_max_coalesced_frames;
+ }
+
+ if (vi->tx_coalesce_usecs != ec->tx_coalesce_usecs ||
+ vi->tx_max_coalesced_frames != ec->tx_max_coalesced_frames) {
+ c.coalesce_usecs = ec->tx_coalesce_usecs;
+ c.max_coalesced_frames = ec->tx_max_coalesced_frames;
+ sg_init_one(&sg, &c, sizeof(c));
+ if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_COALESCE,
+ VIRTIO_NET_CTRL_COALESCE_TX_SET,
+ &sg)) {
+ dev_warn(&dev->dev, "Fail to set tx coalescing\n");
+ return -EINVAL;
+ }
+ vi->tx_coalesce_usecs = ec->tx_coalesce_usecs;
+ vi->tx_max_coalesced_frames = ec->tx_max_coalesced_frames;
+ }
+
+ vi->tx_work_limit = ec->tx_max_coalesced_frames_irq;
+
+ return 0;
+}
+
+static int virtnet_get_coalesce(struct net_device *dev,
+ struct ethtool_coalesce *ec)
+{
+ struct virtnet_info *vi = netdev_priv(dev);
+
+ ec->rx_coalesce_usecs = vi->rx_coalesce_usecs;
+ ec->rx_max_coalesced_frames = vi->rx_max_coalesced_frames;
+ ec->tx_coalesce_usecs = vi->tx_coalesce_usecs;
+ ec->tx_max_coalesced_frames = vi->tx_max_coalesced_frames;
+ ec->tx_max_coalesced_frames_irq = vi->tx_work_limit;
+
+ return 0;
+}
+
static const struct ethtool_ops virtnet_ethtool_ops = {
.get_drvinfo = virtnet_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_ringparam = virtnet_get_ringparam,
.set_channels = virtnet_set_channels,
.get_channels = virtnet_get_channels,
+ .set_coalesce = virtnet_set_coalesce,
+ .get_coalesce = virtnet_get_coalesce,
};

#define MIN_MTU 68
@@ -2048,6 +2114,7 @@ static unsigned int features[] = {
VIRTIO_NET_F_GUEST_ANNOUNCE, VIRTIO_NET_F_MQ,
VIRTIO_NET_F_CTRL_MAC_ADDR,
VIRTIO_F_ANY_LAYOUT,
+ VIRTIO_NET_F_CTRL_COALESCE,
};

static struct virtio_driver virtio_net_driver = {
diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index b5f1677..332009d 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -34,6 +34,7 @@
/* The feature bitmap for virtio net */
#define VIRTIO_NET_F_CSUM 0 /* Host handles pkts w/ partial csum */
#define VIRTIO_NET_F_GUEST_CSUM 1 /* Guest handles pkts w/ partial csum */
+#define VIRTIO_NET_F_CTRL_COALESCE 3 /* Set coalescing */
#define VIRTIO_NET_F_MAC 5 /* Host has given MAC address. */
#define VIRTIO_NET_F_GSO 6 /* Host handles pkts w/ any GSO type */
#define VIRTIO_NET_F_GUEST_TSO4 7 /* Guest can handle TSOv4 in. */
@@ -202,4 +203,15 @@ struct virtio_net_ctrl_mq {
#define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN 1
#define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000

+struct virtio_net_ctrl_coalesce {
+ __u32 coalesce_usecs;
+ __u32 max_coalesced_frames;
+};
+
+#define VIRTIO_NET_CTRL_COALESCE 6
+ #define VIRTIO_NET_CTRL_COALESCE_TX_SET 0
+ #define VIRTIO_NET_CTRL_COALESCE_TX_GET 1
+ #define VIRTIO_NET_CTRL_COALESCE_RX_SET 2
+ #define VIRTIO_NET_CTRL_COALESCE_RX_GET 3
+
#endif /* _LINUX_VIRTIO_NET_H */
--
1.8.3.1