[PATCH vhost v2 10/10] vdpa/mlx5: Parallelize VQ suspend/resume for CVQ MQ command

From: Dragos Tatulea
Date: Fri Aug 16 2024 - 05:06:03 EST


change_num_qps() is still suspending/resuming VQs one by one.
This change switches to parallel suspend/resume.

When increasing the number of queues the flow has changed a bit for
simplicity: the setup_vq() function will always be called before
resume_vqs(). If the VQ is initialized, setup_vq() will exit early. If
the VQ is not initialized, setup_vq() will create it and resume_vqs()
will resume it.

Signed-off-by: Dragos Tatulea <dtatulea@xxxxxxxxxx>
Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxx>
---
drivers/vdpa/mlx5/net/mlx5_vnet.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index d1a01c229110..822092eccb32 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
@@ -2229,25 +2229,27 @@ static int change_num_qps(struct mlx5_vdpa_dev *mvdev, int newqps)
if (err)
return err;

- for (i = cur_vqs - 1; i >= new_vqs; i--) {
- struct mlx5_vdpa_virtqueue *mvq = &ndev->vqs[i];
-
- if (is_resumable(ndev))
- suspend_vq(ndev, mvq);
- else
- teardown_vq(ndev, mvq);
+ if (is_resumable(ndev)) {
+ suspend_vqs(ndev, new_vqs, cur_vqs - new_vqs);
+ } else {
+ for (i = new_vqs; i < cur_vqs; i++)
+ teardown_vq(ndev, &ndev->vqs[i]);
}

ndev->cur_num_vqs = new_vqs;
} else {
ndev->cur_num_vqs = new_vqs;
- for (i = cur_vqs; i < new_vqs; i++) {
- struct mlx5_vdpa_virtqueue *mvq = &ndev->vqs[i];

- err = mvq->initialized ? resume_vq(ndev, mvq) : setup_vq(ndev, mvq, true);
+ for (i = cur_vqs; i < new_vqs; i++) {
+ err = setup_vq(ndev, &ndev->vqs[i], false);
if (err)
goto clean_added;
}
+
+ err = resume_vqs(ndev, cur_vqs, new_vqs - cur_vqs);
+ if (err)
+ goto clean_added;
+
err = modify_rqt(ndev, new_vqs);
if (err)
goto clean_added;
--
2.45.1