[PATCH vhost 5/7] vdpa/mlx5: Parallelize device suspend
From: Dragos Tatulea <dtatulea@nvidia.com>
Date: 2024-08-02 07:24:55
Also in:
lkml
Subsystem:
mellanox mlx5 vdpa driver, the rest, virtio core · Maintainers:
Dragos Tatulea, Linus Torvalds, "Michael S. Tsirkin", Jason Wang
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: Dragos Tatulea <dtatulea@nvidia.com> Reviewed-by: Tariq Toukan <tariqt@nvidia.com> --- drivers/vdpa/mlx5/net/mlx5_vnet.c | 56 ++++++++++++++++--------------- 1 file changed, 29 insertions(+), 27 deletions(-)
diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
index e56a0ee1b725..1887939c5673 100644
--- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
+++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c@@ -1714,49 +1714,51 @@ 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); - 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); + err = modify_virtqueues(ndev, start_vq, num_vqs, MLX5_VIRTIO_NET_Q_OBJECT_STATE_SUSPEND); + if (err) return err; - } - - mvq->avail_idx = attr.available_index; - mvq->used_idx = attr.used_index; - - return 0; -} -static int suspend_vqs(struct mlx5_vdpa_net *ndev) -{ - int err = 0; - int i; + attrs = kcalloc(num_vqs, sizeof(struct mlx5_virtq_attr), GFP_KERNEL); + if (!attrs) + return -ENOMEM; - for (i = 0; i < ndev->cur_num_vqs; i++) { - int local_err = suspend_vq(ndev, &ndev->vqs[i]); + err = query_virtqueues(ndev, start_vq, num_vqs, attrs); + if (err) + goto done; - err = local_err ? local_err : err; + 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; } +done: + kfree(attrs); 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) { int err;
@@ -3137,7 +3139,7 @@ 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)
@@ -3690,7 +3692,7 @@ 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);
--
2.45.2