Commit dcf3eac0 authored by Dragos Tatulea's avatar Dragos Tatulea Committed by Michael S. Tsirkin
Browse files

vdpa/mlx5: Parallelize device suspend 



Currently device suspend works on vqs serially. Building up on previous
changes that converted vq operations to the async api, this patch
parallelizes the device suspend:
1) Suspend all active vqs parallel.
2) Query suspended vqs in parallel.

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 suspend time is reduced from
~37 ms to ~13 ms.

A later patch will remove the link unregister operation which will make
it even faster.

Signed-off-by: default avatarDragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: default avatarTariq Toukan <tariqt@nvidia.com>
Acked-by: default avatarEugenio Pérez <eperezma@redhat.com>
Message-Id: <20240816090159.1967650-7-dtatulea@nvidia.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Tested-by: default avatarLei Yang <leiyang@redhat.com>
parent 61674c15

drivers/vdpa/mlx5/net/mlx5_vnet.c

+29 −27
Original line number Diff line number Diff line
@@ -1630,47 +1630,49 @@ static int modify_virtqueues(struct mlx5_vdpa_net *ndev, int start_vq, int num_v 
	return err;

}



static int suspend_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)

static int suspend_vqs(struct mlx5_vdpa_net *ndev, int start_vq, int num_vqs)

{

	struct mlx5_virtq_attr attr;

	struct mlx5_vdpa_virtqueue *mvq;

	struct mlx5_virtq_attr *attrs;

	int vq_idx, i;

	int err;



	if (start_vq >= ndev->cur_num_vqs)

		return -EINVAL;



	mvq = &ndev->vqs[start_vq];

	if (!mvq->initialized)

		return 0;



	if (mvq->fw_state != MLX5_VIRTIO_NET_Q_OBJECT_STATE_RDY)

		return 0;



	err = modify_virtqueues(ndev, mvq->index, 1, MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND);

	if (err) {

		mlx5_vdpa_err(&ndev->mvdev, "modify to suspend failed, err: %d\n", err);

	err = modify_virtqueues(ndev, start_vq, num_vqs, MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND);

	if (err)

		return err;

	}



	err = query_virtqueues(ndev, mvq->index, 1, &attr);

	if (err) {

		mlx5_vdpa_err(&ndev->mvdev, "failed to query virtqueue, err: %d\n", err);

		return err;

	}

	attrs = kcalloc(num_vqs, sizeof(struct mlx5_virtq_attr), GFP_KERNEL);

	if (!attrs)

		return -ENOMEM;



	mvq->avail_idx = attr.available_index;

	mvq->used_idx = attr.used_index;

	err = query_virtqueues(ndev, start_vq, num_vqs, attrs);

	if (err)

		goto done;



	return 0;

	for (i = 0, vq_idx = start_vq; i < num_vqs; i++, vq_idx++) {

		mvq = &ndev->vqs[vq_idx];

		mvq->avail_idx = attrs[i].available_index;

		mvq->used_idx = attrs[i].used_index;

	}



static int suspend_vqs(struct mlx5_vdpa_net *ndev)

{

	int err = 0;

	int i;



	for (i = 0; i < ndev->cur_num_vqs; i++) {

		int local_err = suspend_vq(ndev, &ndev->vqs[i]);



		err = local_err ? local_err : err;

done:

	kfree(attrs);

	return err;

}



	return err;

static int suspend_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)

{

	return suspend_vqs(ndev, mvq->index, 1);

}



static int resume_vq(struct mlx5_vdpa_net *ndev, struct mlx5_vdpa_virtqueue *mvq)
@@ -3053,7 +3055,7 @@ static int mlx5_vdpa_change_map(struct mlx5_vdpa_dev *mvdev, 
	bool teardown = !is_resumable(ndev);

	int err;



	suspend_vqs(ndev);

	suspend_vqs(ndev, 0, ndev->cur_num_vqs);

	if (teardown) {

		err = save_channels_info(ndev);

		if (err)
@@ -3606,7 +3608,7 @@ static int mlx5_vdpa_suspend(struct vdpa_device *vdev) 


	down_write(&ndev->reslock);

	unregister_link_notifier(ndev);

	err = suspend_vqs(ndev);

	err = suspend_vqs(ndev, 0, ndev->cur_num_vqs);

	mlx5_vdpa_cvq_suspend(mvdev);

	mvdev->suspended = true;

	up_write(&ndev->reslock);