diff mbox series

[net-next,v3,2/4] virtio_net: enable irq for the control vq

Message ID 20240606061446.127802-3-hengqi@linux.alibaba.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series virtio_net: enable the irq for ctrlq | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 901 this patch: 901
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers success CCed 9 of 9 maintainers
netdev/build_clang success Errors and warnings before: 905 this patch: 905
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 905 this patch: 905
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 52 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Heng Qi June 6, 2024, 6:14 a.m. UTC 
If the device does not respond to a request for a long time,
then control vq polling elevates CPU utilization, a problem that
exacerbates with more command requests.

Enabling control vq's irq is advantageous for the guest, and
this still doesn't support concurrent requests.

Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Heng Qi <hengqi@linux.alibaba.com>
---
 drivers/net/virtio_net.c | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 0f872936d6ed..823a9dca51c1 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -372,6 +372,8 @@  struct virtio_net_ctrl_rss {
 struct control_buf {
 	struct virtio_net_ctrl_hdr hdr;
 	virtio_net_ctrl_ack status;
+	/* Wait for the device to complete the cvq request. */
+	struct completion completion;
 };
 
 struct virtnet_info {
@@ -664,6 +666,13 @@  static bool virtqueue_napi_complete(struct napi_struct *napi,
 	return false;
 }
 
+static void virtnet_cvq_done(struct virtqueue *cvq)
+{
+	struct virtnet_info *vi = cvq->vdev->priv;
+
+	complete(&vi->ctrl->completion);
+}
+
 static void skb_xmit_done(struct virtqueue *vq)
 {
 	struct virtnet_info *vi = vq->vdev->priv;
@@ -2723,14 +2732,8 @@  static bool virtnet_send_command_reply(struct virtnet_info *vi,
 	if (unlikely(!virtqueue_kick(vi->cvq)))
 		goto unlock;
 
-	/* Spin for a response, the kick causes an ioport write, trapping
-	 * into the hypervisor, so the request should be handled immediately.
-	 */
-	while (!virtqueue_get_buf(vi->cvq, &tmp) &&
-	       !virtqueue_is_broken(vi->cvq)) {
-		cond_resched();
-		cpu_relax();
-	}
+	wait_for_completion(&vi->ctrl->completion);
+	virtqueue_get_buf(vi->cvq, &tmp);
 
 unlock:
 	mutex_unlock(&vi->cvq_lock);
@@ -5314,7 +5317,7 @@  static int virtnet_find_vqs(struct virtnet_info *vi)
 
 	/* Parameters for control virtqueue, if any */
 	if (vi->has_cvq) {
-		callbacks[total_vqs - 1] = NULL;
+		callbacks[total_vqs - 1] = virtnet_cvq_done;
 		names[total_vqs - 1] = "control";
 	}
 
@@ -5834,6 +5837,7 @@  static int virtnet_probe(struct virtio_device *vdev)
 	if (vi->has_rss || vi->has_rss_hash_report)
 		virtnet_init_default_rss(vi);
 
+	init_completion(&vi->ctrl->completion);
 	enable_rx_mode_work(vi);
 
 	/* serialize netdev register + virtio_device_ready() with ndo_open() */