Commit 55a7cb05 authored by Dragos Tatulea's avatar Dragos Tatulea Committed by Michael S. Tsirkin
Browse files

vdpa/mlx5: Keep notifiers during suspend but ignore 



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: default avatarDragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: default avatarTariq Toukan <tariqt@nvidia.com>
Acked-by: default avatarEugenio Pérez <eperezma@redhat.com>
Message-Id: <20240816090159.1967650-9-dtatulea@nvidia.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Tested-by: default avatarLei Yang <leiyang@redhat.com>
parent 5eb8c7eb

drivers/vdpa/mlx5/net/mlx5_vnet.c

+4 −2
Original line number Diff line number Diff line
@@ -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;