Re: [PATCH net-next v2] documentation: networking: Add NAPI config

[Bagas Sanjaya <bagasdotme@gmail.com>]

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On Tue, Feb 11, 2025 at 08:06:03PM +0000, Joe Damato wrote:
> diff --git a/Documentation/networking/napi.rst
> b/Documentation/networking/napi.rst
> index f970a2be271a..d0e3953cae6a 100644
> --- a/Documentation/networking/napi.rst
> +++ b/Documentation/networking/napi.rst
> @@ -171,12 +171,43 @@ a channel as an IRQ/NAPI which services queues
> of a given type. For example,
>  a configuration of 1 ``rx``, 1 ``tx`` and 1 ``combined`` channel is expected
>  to utilize 3 interrupts, 2 Rx and 2 Tx queues.
> 
> +Persistent NAPI config
> +----------------------
> +
> +Drivers often allocate and free NAPI instances dynamically. This leads to loss
> +of NAPI-related user configuration each time NAPI instances are reallocated.
> +The netif_napi_add_config() API prevents this loss of configuration by
> +associating each NAPI instance with a persistent NAPI configuration based on
> +a driver defined index value, like a queue number.
> +
> +Using this API allows for persistent NAPI IDs (among other settings), which can
> +be beneficial to userspace programs using ``SO_INCOMING_NAPI_ID``. See the
> +sections below for other NAPI configuration settings.
> +
> +Drivers should try to use netif_napi_add_config() whenever possible.
> +
>  User API
>  ========
> 
>  User interactions with NAPI depend on NAPI instance ID. The instance IDs
>  are only visible to the user thru the ``SO_INCOMING_NAPI_ID`` socket option.
> -It's not currently possible to query IDs used by a given device.
> +
> +Users can query NAPI IDs for a device or device queue using netlink. This can
> +be done programmatically in a user application or by using a script included in
> +the kernel source tree: ``tools/net/ynl/pyynl/cli.py``.
> +
> +For example, using the script to dump all of the queues for a device (which
> +will reveal each queue's NAPI ID):
> +
> +.. code-block:: bash
> +
> +   $ kernel-source/tools/net/ynl/pyynl/cli.py \
> +             --spec Documentation/netlink/specs/netdev.yaml \
> +             --dump queue-get \
> +             --json='{"ifindex": 2}'
> +
> +See ``Documentation/netlink/specs/netdev.yaml`` for more details on
> +available operations and attributes.
> 
>  Software IRQ coalescing
>  -----------------------
> 

Looks good, thanks!

Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>

-- 
An old man doll... just what I always wanted! - Clara

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