Re: [dpdk-dev] [RFC PATCH 2/2] ethdev: add capability to keep indirect actions on restart

From: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
To: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Cc: <dev@dpdk.org>, Matan Azrad <matan@nvidia.com>,
	Ori Kam <orika@nvidia.com>,
	"Thomas Monjalon" <thomas@monjalon.net>,
	Ferruh Yigit <ferruh.yigit@intel.com>,
	"Andrew Rybchenko" <andrew.rybchenko@oktetlabs.ru>
Subject: Re: [dpdk-dev] [RFC PATCH 2/2] ethdev: add capability to keep indirect actions on restart
Date: Mon, 27 Sep 2021 14:21:21 +0300	[thread overview]
Message-ID: <20210927142121.7cafde58@sovereign> (raw)
In-Reply-To: <20210901085516.3647814-3-dkozlyuk@nvidia.com>

2021-09-01 11:55 (UTC+0300), Dmitry Kozlyuk:
> rte_flow_action_handle_create() did not mention what happens
> with an indirect action when a device is stopped, possibly reconfigured,
> and started again. It is natural for some indirect actions to be
> persistent, like counters and meters; keeping others just saves
> application time and complexity. However, not all PMDs can support it.
> It is proposed to add a device capability to indicate if indirect actions
> are kept across the above sequence or implicitly destroyed.
> 
> It may happen that in the future a PMD acquires support for a type of
> indirect actions that it cannot keep across a restart. It is undesirable
> to stop advertising the capability so that applications that don't use
> actions of the problematic type can still take advantage of it.
> This is why PMDs are allowed to keep only a subset of indirect actions
> provided that the vendor mandatorily documents it.
> 
> If the device is being reconfigured in a way that is incompatible with
> an existing indirect action, PMD is required to report an error.
> This is mandatory, because flow API does not supply users with
> capabilities, so this is the only way for a user to learn that
> configuration is invalid. For example, if queue count changes and RSS
> indirect action specifies queues that are going away, the user must
> update the action before removing the queues or remove the action and
> all flow rules that were using it.
> 
> Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
> Acked-by: Matan Azrad <matan@nvidia.com>
> Acked-by: Ori Kam <orika@nvidia.com>
> ---
>  doc/guides/prog_guide/rte_flow.rst | 12 ++++++++++++
>  lib/ethdev/rte_ethdev.h            |  5 +++++
>  2 files changed, 17 insertions(+)
> 
> [...]

Hello, any opinions?

Just noticed that I forgot to Cc everyone in the cover letter with context:

	http://inbox.dpdk.org/dev/20210901085516.3647814-1-dkozlyuk@nvidia.com/