[PATCH vhost v2 07/10] vdpa/mlx5: Parallelize device resume
From: Dragos Tatulea <dtatulea@nvidia.com>
Date: 2024-08-16 09:03:01
Also in:
kvm, lkml
Subsystem:
mellanox mlx5 vdpa driver, the rest, virtio core · Maintainers:
Dragos Tatulea, Linus Torvalds, "Michael S. Tsirkin", Jason Wang
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> --- drivers/vdpa/mlx5/net/mlx5_vnet.c | 40 +++++++++++-------------------- 1 file changed, 14 insertions(+), 26 deletions(-)
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index 5fba16c80dbb..0773bec917be 100644
--- 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);
--
2.45.1