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vdpa/mlx5: Keep notifiers during suspend but ignore

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Unregistering notifiers is a costly operation. Instead of removing
the notifiers during device suspend and adding them back at resume,
simply ignore the call when the device is suspended.

At resume time call queue_link_work() to make sure that the device state
is propagated in case there were changes.

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
~13 ms to ~2.5 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: <20240816090159.1967650-9-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Tested-by: Lei Yang <leiyang@redhat.com>
This commit is contained in:
Dragos Tatulea 2024-08-16 12:01:57 +03:00 committed by Michael S. Tsirkin
parent 5eb8c7eb1e
commit 55a7cb05b0
1 changed files with 4 additions and 2 deletions
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6
drivers/vdpa/mlx5/net/mlx5_vnet.c
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@ -2850,6 +2850,9 @@ static int event_handler(struct notifier_block *nb, unsigned long event, void *p
struct mlx5_eqe *eqe = param;
int ret = NOTIFY_DONE;
if (ndev->mvdev.suspended)
return NOTIFY_DONE;
if (event == MLX5_EVENT_TYPE_PORT_CHANGE) {
switch (eqe->sub_type) {
case MLX5_PORT_CHANGE_SUBTYPE_DOWN:
@ -3595,7 +3598,6 @@ static int mlx5_vdpa_suspend(struct vdpa_device *vdev)
mlx5_vdpa_info(mvdev, "suspending device\n");
down_write(&ndev->reslock);
unregister_link_notifier(ndev);
err = suspend_vqs(ndev, 0, ndev->cur_num_vqs);
mlx5_vdpa_cvq_suspend(mvdev);
mvdev->suspended = true;
@ -3617,7 +3619,7 @@ static int mlx5_vdpa_resume(struct vdpa_device *vdev)
down_write(&ndev->reslock);
mvdev->suspended = false;
err = resume_vqs(ndev, 0, ndev->cur_num_vqs);
register_link_notifier(ndev);
queue_link_work(ndev);
up_write(&ndev->reslock);
return err;