vdpa/mlx5: Parallelize device resume

Currently device resume works on vqs serially. Building up on previous
changes that converted vq operations to the async api, this patch
parallelizes the device resume.

For 1 vDPA device x 32 VQs (16 VQPs) attached to a large VM (256 GB RAM,
32 CPUs x 2 threads per core), the device resume time is reduced from
~16 ms to ~4.5 ms.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Acked-by: Eugenio Pérez <eperezma@redhat.com>
Message-Id: <20240816090159.1967650-8-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 17f74b1f0644077b8eb23d559265bd29e5f3681c..fc9fb8d9ac4fa8c8e455682b03b7c77b9045a616 100644 (file)
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -1675,10 +1675,15 @@ static int suspend_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mv
        return suspend_vqs(ndev, mvq->index, 1);
 }
 
-static int resume_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
+static int resume_vqs(struct mlx5_vdpa_net *ndev, int start_vq, int num_vqs)
 {
+       struct mlx5_vdpa_virtqueue *mvq;
        int err;
 
+       if (start_vq >= ndev->mvdev.max_vqs)
+               return -EINVAL;
+
+       mvq = &ndev->vqs[start_vq];
        if (!mvq->initialized)
                return 0;
 
@@ -1690,13 +1695,9 @@ static int resume_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq
                /* Due to a FW quirk we need to modify the VQ fields first then change state.
                 * This should be fixed soon. After that, a single command can be used.
                 */
-               err = modify_virtqueues(ndev, mvq->index, 1, mvq->fw_state);
-               if (err) {
-                       mlx5_vdpa_err(&ndev->mvdev,
-                               "modify vq properties failed for vq %u, err: %d\n",
-                               mvq->index, err);
+               err = modify_virtqueues(ndev, start_vq, num_vqs, mvq->fw_state);
+               if (err)
                        return err;
-               }
                break;
        case MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND:
                if (!is_resumable(ndev)) {
@@ -1712,25 +1713,12 @@ static int resume_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq
                return -EINVAL;
        }
 
-       err = modify_virtqueues(ndev, mvq->index, 1, MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY);
-       if (err)
-               mlx5_vdpa_err(&ndev->mvdev, "modify to resume failed for vq %u, err: %d\n",
-                             mvq->index, err);
-
-       return err;
+       return modify_virtqueues(ndev, start_vq, num_vqs, MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY);
 }
 
-static int resume_vqs(struct mlx5_vdpa_net *ndev)
+static int resume_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
 {
-       int err = 0;
-
-       for (int i = 0; i < ndev->cur_num_vqs; i++) {
-               int local_err = resume_vq(ndev, &ndev->vqs[i]);
-
-               err = local_err ? local_err : err;
-       }
-
-       return err;
+       return resume_vqs(ndev, mvq->index, 1);
 }
 
 static void teardown_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
@@ -3080,7 +3068,7 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev,
                        return err;
        }
 
-       resume_vqs(ndev);
+       resume_vqs(ndev, 0, ndev->cur_num_vqs);
 
        return 0;
 }
@@ -3204,7 +3192,7 @@ static void mlx5_vdpa_set_status(struct vdpa_device *vdev, u8 status)
                                teardown_vq_resources(ndev);
 
                        if (ndev->setup) {
-                               err = resume_vqs(ndev);
+                               err = resume_vqs(ndev, 0, ndev->cur_num_vqs);
                                if (err) {
                                        mlx5_vdpa_warn(mvdev, "failed to resume VQs\n");
                                        goto err_driver;
@@ -3628,7 +3616,7 @@ static int mlx5_vdpa_resume(struct vdpa_device *vdev)
 
        down_write(&ndev->reslock);
        mvdev->suspended = false;
-       err = resume_vqs(ndev);
+       err = resume_vqs(ndev, 0, ndev->cur_num_vqs);
        register_link_notifier(ndev);
        up_write(&ndev->reslock);