Re: [PATCH v2 02/15] vdpa/mlx5: support pre create virtq resource

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 6/16/22 04:29, Li Zhang wrote:
> From: Yajun Wu <yajunw@nvidia.com>
> 
> The motivation of this change is to reduce vDPA device queue creation
> time by create some queue resource in vDPA device probe stage.

s/create/creating/

> 
> In VM live migration scenario, this can reduce 0.8ms for each queue
> creation, thus reduce LM network downtime.
> 
> To create queue resource(umem/counter) in advance, we need to know
> virtio queue depth and max number of queue VM will use.
> 
> Introduce two new devargs: queues(max queue pair number) and queue_size
> (queue depth). Two args must be both provided, if only one argument
> provided, the argument will be ignored and no pre-creation.
> 
> The queues and queue_size must also be identical to vhost configuration
> driver later receive. Otherwise either the pre-create resource is wasted
> or missing or the resource need destroy and recreate(in case queue_size
> mismatch).
> 
> Pre-create umem/counter will keep alive until vDPA device removal.
> 
> Signed-off-by: Yajun Wu <yajunw@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>
> ---
>   doc/guides/vdpadevs/mlx5.rst  | 14 +++++++
>   drivers/vdpa/mlx5/mlx5_vdpa.c | 75 ++++++++++++++++++++++++++++++++++-
>   drivers/vdpa/mlx5/mlx5_vdpa.h |  2 +
>   3 files changed, 89 insertions(+), 2 deletions(-)
> 

Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime