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Date: Sun, 15 May 2022 09:43:30 +0300
From: Alvaro Karsz <alvaro.karsz@...id-run.com>
To: netdev@...r.kernel.org
Cc: rabeeh@...id-run.com, Alvaro Karsz <alvaro.karsz@...id-run.com>,
"Michael S. Tsirkin" <mst@...hat.com>,
Jason Wang <jasowang@...hat.com>,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Subject: [PATCH v2] net: virtio_net: support interrupt coalescing
Control a Virtio network device interrupt coalescing parameters
using the control virtqueue.
New VirtIO network feature: VIRTIO_NET_F_INTR_COAL.
A device that supports this fetature can receive
VIRTIO_NET_CTRL_INTR_COAL control commands.
- VIRTIO_NET_CTRL_INTR_COAL_USECS_SET:
change the rx-usecs and tx-usecs parameters.
rx-usecs - Time to delay an RX interrupt after packet arrival in
microseconds.
tx-usecs - Time to delay a TX interrupt after a sending a packet
in microseconds.
- VIRTIO_NET_CTRL_INTR_COAL_FRAMES_SET:
change the rx-max-frames and tx-max-frames parameters.
rx-max-frames: Number of packets to delay an RX interrupt after
packet arrival.
tx-max-frames: Number of packets to delay a TX interrupt after
sending a packet.
Signed-off-by: Alvaro Karsz <alvaro.karsz@...id-run.com>
---
v2:
- usage of __virtio vairables.
- send commands to device only if the values have changed.
---
drivers/net/virtio_net.c | 116 ++++++++++++++++++++++++++++----
include/uapi/linux/virtio_net.h | 34 +++++++++-
2 files changed, 136 insertions(+), 14 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index cbba9d2e8f3..e40f453edb9 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -261,6 +261,12 @@ struct virtnet_info {
u8 duplex;
u32 speed;
+ /* Interrupt coalescing settings */
+ u32 tx_usecs;
+ u32 rx_usecs;
+ u32 tx_frames_max;
+ u32 rx_frames_max;
+
unsigned long guest_offloads;
unsigned long guest_offloads_capable;
@@ -2594,19 +2600,83 @@ static int virtnet_set_coalesce(struct net_device *dev,
{
struct virtnet_info *vi = netdev_priv(dev);
int i, napi_weight;
+ struct scatterlist sgs_usecs, sgs_frames;
+ struct virtio_net_ctrl_coal_frames c_frames;
+ struct virtio_net_ctrl_coal_usec c_usecs;
+ bool update_napi,
+ intr_coal = virtio_has_feature(vi->vdev, VIRTIO_NET_F_INTR_COAL);
+
+ /* rx_coalesce_usecs/tx_coalesce_usecs are supported only
+ * if VIRTIO_NET_F_INTR_COAL feature is set.
+ */
+ if (!intr_coal && (ec->rx_coalesce_usecs || ec->tx_coalesce_usecs))
+ return -EOPNOTSUPP;
- if (ec->tx_max_coalesced_frames > 1 ||
- ec->rx_max_coalesced_frames != 1)
+ if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_INTR_COAL)) {
+ /* Send usec command only if value has changed */
+ if (ec->tx_coalesce_usecs != vi->tx_usecs ||
+ ec->rx_coalesce_usecs != vi->rx_usecs) {
+ c_usecs.tx_usecs = cpu_to_virtio32(vi->vdev, ec->tx_coalesce_usecs);
+ c_usecs.rx_usecs = cpu_to_virtio32(vi->vdev, ec->rx_coalesce_usecs);
+ sg_init_one(&sgs_usecs, &c_usecs, sizeof(c_usecs));
+
+ if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_INTR_COAL,
+ VIRTIO_NET_CTRL_INTR_COAL_USECS_SET,
+ &sgs_usecs))
+ return -EINVAL;
+
+ /* Save parameters */
+ vi->tx_usecs = ec->tx_coalesce_usecs;
+ vi->rx_usecs = ec->rx_coalesce_usecs;
+ }
+
+ /* Send frames command only if value has changed */
+ if (ec->tx_max_coalesced_frames != vi->tx_frames_max ||
+ ec->rx_max_coalesced_frames != vi->rx_frames_max) {
+ c_frames.tx_frames_max = cpu_to_virtio32(vi->vdev,
+ ec->tx_max_coalesced_frames);
+ c_frames.rx_frames_max = cpu_to_virtio32(vi->vdev,
+ ec->rx_max_coalesced_frames);
+ sg_init_one(&sgs_frames, &c_frames, sizeof(c_frames));
+
+ if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_INTR_COAL,
+ VIRTIO_NET_CTRL_INTR_COAL_FRAMES_SET,
+ &sgs_frames))
+ return -EINVAL;
+
+ /* Save parameters */
+ vi->tx_frames_max = ec->tx_max_coalesced_frames;
+ vi->rx_frames_max = ec->rx_max_coalesced_frames;
+ }
+ }
+
+ /* Should we update NAPI? */
+ update_napi = ec->tx_max_coalesced_frames <= 1 &&
+ ec->rx_max_coalesced_frames == 1;
+
+ /* If interrupt coalesing feature is not set, and we can't update NAPI, return an error */
+ if (!intr_coal && !update_napi)
return -EINVAL;
- 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;
- for (i = 0; i < vi->max_queue_pairs; i++)
- vi->sq[i].napi.weight = napi_weight;
+ if (update_napi) {
+ napi_weight = ec->tx_max_coalesced_frames ? NAPI_POLL_WEIGHT : 0;
+ if (napi_weight ^ vi->sq[0].napi.weight) {
+ if (dev->flags & IFF_UP) {
+ /* If Interrupt coalescing feature is not set, return an error.
+ * Otherwise exit without changing the NAPI paremeters
+ */
+ if (!intr_coal)
+ return -EBUSY;
+
+ goto exit;
+ }
+
+ for (i = 0; i < vi->max_queue_pairs; i++)
+ vi->sq[i].napi.weight = napi_weight;
+ }
}
+exit:
return 0;
}
@@ -2616,14 +2686,25 @@ static int virtnet_get_coalesce(struct net_device *dev,
struct netlink_ext_ack *extack)
{
struct ethtool_coalesce ec_default = {
- .cmd = ETHTOOL_GCOALESCE,
- .rx_max_coalesced_frames = 1,
+ .cmd = ETHTOOL_GCOALESCE
};
+
struct virtnet_info *vi = netdev_priv(dev);
+ bool intr_coal = virtio_has_feature(vi->vdev, VIRTIO_NET_F_INTR_COAL);
+
+ /* Add Interrupt coalescing settings */
+ if (intr_coal) {
+ ec_default.rx_coalesce_usecs = vi->rx_usecs;
+ ec_default.tx_coalesce_usecs = vi->tx_usecs;
+ ec_default.tx_max_coalesced_frames = vi->tx_frames_max;
+ ec_default.rx_max_coalesced_frames = vi->rx_frames_max;
+ } else {
+ ec_default.rx_max_coalesced_frames = 1;
+ }
memcpy(ec, &ec_default, sizeof(ec_default));
- if (vi->sq[0].napi.weight)
+ if (!intr_coal && vi->sq[0].napi.weight)
ec->tx_max_coalesced_frames = 1;
return 0;
@@ -2743,7 +2824,7 @@ 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,
+ .supported_coalesce_params = ETHTOOL_COALESCE_MAX_FRAMES | ETHTOOL_COALESCE_USECS,
.get_drvinfo = virtnet_get_drvinfo,
.get_link = ethtool_op_get_link,
.get_ringparam = virtnet_get_ringparam,
@@ -3423,6 +3504,8 @@ static bool virtnet_validate_features(struct virtio_device *vdev)
VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_RSS,
"VIRTIO_NET_F_CTRL_VQ") ||
VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_HASH_REPORT,
+ "VIRTIO_NET_F_CTRL_VQ") ||
+ VIRTNET_FAIL_ON(vdev, VIRTIO_NET_F_INTR_COAL,
"VIRTIO_NET_F_CTRL_VQ"))) {
return false;
}
@@ -3558,6 +3641,13 @@ static int virtnet_probe(struct virtio_device *vdev)
if (virtio_has_feature(vdev, VIRTIO_NET_F_MRG_RXBUF))
vi->mergeable_rx_bufs = true;
+ if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_INTR_COAL)) {
+ vi->rx_usecs = 0;
+ vi->tx_usecs = 0;
+ vi->tx_frames_max = 0;
+ vi->rx_frames_max = 0;
+ }
+
if (virtio_has_feature(vdev, VIRTIO_NET_F_HASH_REPORT))
vi->has_rss_hash_report = true;
@@ -3786,7 +3876,7 @@ static struct virtio_device_id id_table[] = {
VIRTIO_NET_F_CTRL_MAC_ADDR, \
VIRTIO_NET_F_MTU, VIRTIO_NET_F_CTRL_GUEST_OFFLOADS, \
VIRTIO_NET_F_SPEED_DUPLEX, VIRTIO_NET_F_STANDBY, \
- VIRTIO_NET_F_RSS, VIRTIO_NET_F_HASH_REPORT
+ VIRTIO_NET_F_RSS, VIRTIO_NET_F_HASH_REPORT, VIRTIO_NET_F_INTR_COAL
static unsigned int features[] = {
VIRTNET_FEATURES,
diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 3f55a4215f1..05da9eb6ad9 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -56,7 +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_INTR_COAL 24 /* Guest can handle Interrupt coalescing */
#define VIRTIO_NET_F_HASH_REPORT 57 /* Supports hash report */
#define VIRTIO_NET_F_RSS 60 /* Supports RSS RX steering */
#define VIRTIO_NET_F_RSC_EXT 61 /* extended coalescing info */
@@ -355,4 +355,36 @@ struct virtio_net_hash_config {
#define VIRTIO_NET_CTRL_GUEST_OFFLOADS 5
#define VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET 0
+/*
+ * Control interrupt coalescing.
+ *
+ * Request the device to change the interrupt coalescing parameters.
+ *
+ * Available with the VIRTIO_NET_F_INTR_COAL feature bit.
+ */
+#define VIRTIO_NET_CTRL_INTR_COAL 6
+/*
+ * Set the rx-usecs/tx-usecs patameters.
+ * rx-usecs - Number of microseconds to delay an RX interrupt after packet arrival.
+ * tx-usecs - Number of microseconds to delay a TX interrupt after a sending a packet.
+ */
+struct virtio_net_ctrl_coal_usec {
+ __virtio32 tx_usecs;
+ __virtio32 rx_usecs;
+};
+
+#define VIRTIO_NET_CTRL_INTR_COAL_USECS_SET 0
+
+/*
+ * Set the rx-max-frames/tx-max-frames patameters.
+ * rx-max-frames - Number of packets to delay an RX interrupt after packet arrival.
+ * tx-max-frames - Number of packets to delay a TX interrupt after sending a packet.
+ */
+struct virtio_net_ctrl_coal_frames {
+ __virtio32 tx_frames_max;
+ __virtio32 rx_frames_max;
+};
+
+#define VIRTIO_NET_CTRL_INTR_COAL_FRAMES_SET 1
+
#endif /* _UAPI_LINUX_VIRTIO_NET_H */
--
2.32.0
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