[dpdk-dev] [PATCH 4/4] doc: improve vhost zero copy guide

[Maxime Coquelin]

On 2/22/19 3:42 AM, Tiwei Bie wrote:
> Highlight that vhost zero copy mbufs should be consumed
> as soon as possible.
> 
> Signed-off-by: Tiwei Bie <tiwei.bie at intel.com>
> ---
>   doc/guides/prog_guide/vhost_lib.rst | 3 +++
>   1 file changed, 3 insertions(+)
> 
> diff --git a/doc/guides/prog_guide/vhost_lib.rst b/doc/guides/prog_guide/vhost_lib.rst
> index c77df338f..a86c07a62 100644
> --- a/doc/guides/prog_guide/vhost_lib.rst
> +++ b/doc/guides/prog_guide/vhost_lib.rst
> @@ -92,6 +92,9 @@ The following is an overview of some key Vhost API functions:
>         to use vfio-pci driver, please insert vfio-pci kernel module in noiommu
>         mode.
>   
> +    * The consumer of zero copy mbufs should consume these mbufs as soon as
> +      possible, otherwise it may block the operations in vhost.
> +
>     - ``RTE_VHOST_USER_IOMMU_SUPPORT``
>   
>       IOMMU support will be enabled when this flag is set. It is disabled by
> 

Indeed, and it may also block QEMU. That's what I find really fragile
with dequeue zero-copy.

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

Thanks,
Maxime