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

[Li Zhang <lizh@nvidia.com>]

Thanks for your comment and will fix it on V3.

Regards,
Li Zhang

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Friday, June 17, 2022 11:37 PM
> To: Li Zhang <lizh@nvidia.com>; Ori Kam <orika@nvidia.com>; Slava
> Ovsiienko <viacheslavo@nvidia.com>; Matan Azrad <matan@nvidia.com>;
> Shahaf Shuler <shahafs@nvidia.com>
> Cc: dev@dpdk.org; NBU-Contact-Thomas Monjalon (EXTERNAL)
> <thomas@monjalon.net>; Raslan Darawsheh <rasland@nvidia.com>; Roni
> Bar Yanai <roniba@nvidia.com>; Yajun Wu <yajunw@nvidia.com>
> Subject: Re: [PATCH v2 02/15] vdpa/mlx5: support pre create virtq resource
> 
> External email: Use caution opening links or attachments
> 
> 
> 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