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From: Jakub Kicinski <kuba@kernel.org>
To: Jacob Keller <jacob.e.keller@intel.com>
Cc: Jiri Pirko <jiri@resnulli.us>, Moshe Shemesh <moshe@mellanox.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	Jiri Pirko <jiri@mellanox.com>,
	Vasundhara Volam <vasundhara-v.volam@broadcom.com>
Subject: Re: [PATCH net-next RFC 01/13] devlink: Add reload level option to devlink reload command
Date: Tue, 28 Jul 2020 11:44:58 -0700	[thread overview]
Message-ID: <20200728114458.762b5396@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <464add44-3ab1-21b8-3dba-a88202350bb9@intel.com>

On Tue, 28 Jul 2020 09:47:00 -0700 Jacob Keller wrote:
> On 7/28/2020 6:58 AM, Jiri Pirko wrote:
> > But this is needed to maintain the existing behaviour which is different
> > for different drivers.
> 
> Which drivers behave differently here?

I think Jiri refers to mlxsw vs mlx5.

mlxsw loads firmware on probe, by default at least. So reloading the
driver implies a FW reset. NIC drivers OTOH don't generally load FW
so they didn't reset FW.

Now since we're redefining the API from "do a reload so that driverinit
params are applied" (or "so that all netdevs get spawned in a new
netns") to "do a reset of depth X" we have to change the paradigm.

What I was trying to suggest is that we should not have to re-define
the API like this.

From user perspective what's important is what the reset achieves (and
perhaps how destructive it is). We can define the reset levels as:

$ devlink dev reload pci/0000:82:00.0 net-ns-respawn
$ devlink dev reload pci/0000:82:00.0 driver-param-init
$ devlink dev reload pci/0000:82:00.0 fw-activate

combining should be possible when user wants multiple things to happen:

$ devlink dev reload pci/0000:82:00.0 fw-activate driver-param-init


Then we have the use case of a "live reset" which is slightly
under-defined right now IMHO, but we can extend it as:

$ devlink dev reload pci/0000:82:00.0 fw-activate --live


We can also add the "reset level" specifier - for the cases where
device is misbehaving:

$ devlink dev reload pci/0000:82:00.0 level [driver|fw|hardware]


But I don't think that we can go from the current reload command
cleanly to just a level reset. The driver-specific default is a bad
smell which indicates we're changing semantics from what user wants 
to what the reset depth is. Our semantics with the patch as it stands
are in fact:
 - if you want to load new params or change netns, don't pass the level
   - the "driver default" workaround dictates the right reset level for
   param init;
 - if you want to activate new firmware - select the reset level you'd
   like from the reset level options.

  reply	other threads:[~2020-07-28 18:45 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27 11:02 [PATCH net-next RFC 00/13] Add devlink reload level option Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 01/13] devlink: Add reload level option to devlink reload command Moshe Shemesh
2020-07-28  0:58   ` Jakub Kicinski
2020-07-28 13:58     ` Jiri Pirko
2020-07-28 16:47       ` Jacob Keller
2020-07-28 18:44         ` Jakub Kicinski [this message]
2020-07-28 19:18           ` Jacob Keller
2020-07-28 20:06             ` Jakub Kicinski
2020-07-29 14:54               ` Moshe Shemesh
2020-07-29 21:07                 ` Jakub Kicinski
2020-07-30 12:30                   ` Moshe Shemesh
2020-07-30 23:11                     ` Jakub Kicinski
2020-08-01 21:32                       ` Moshe Shemesh
2020-08-03 14:14                         ` Jiri Pirko
2020-08-03 20:57                           ` Jakub Kicinski
2020-08-04 10:04                             ` Jiri Pirko
2020-08-04 20:39                               ` Jakub Kicinski
2020-08-05 11:02                                 ` Jiri Pirko
2020-08-06 18:25                                   ` Jakub Kicinski
2020-08-06 22:56                                     ` Jacob Keller
2020-08-09 13:21                                     ` Moshe Shemesh
2020-08-10 16:53                                       ` Jakub Kicinski
2020-08-10 17:09                                         ` Jacob Keller
2020-08-10 18:17                                           ` Jakub Kicinski
2020-08-11  5:46                                         ` Jiri Pirko
2020-07-27 11:02 ` [PATCH net-next RFC 02/13] devlink: Add reload levels data to dev get Moshe Shemesh
2020-07-28  0:58   ` Jakub Kicinski
2020-07-29 14:37     ` Moshe Shemesh
2020-07-29 21:11       ` Jakub Kicinski
2020-07-30 12:05         ` Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 03/13] net/mlx5: Add functions to set/query MFRL register Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 04/13] net/mlx5: Set cap for pci sync for fw update event Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 05/13] net/mlx5: Handle sync reset request event Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 06/13] net/mlx5: Handle sync reset now event Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 07/13] net/mlx5: Handle sync reset abort event Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 08/13] net/mlx5: Add support for devlink reload level fw reset Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 09/13] devlink: Add enable_remote_dev_reset generic parameter Moshe Shemesh
2020-07-28  0:59   ` Jakub Kicinski
2020-07-29 14:42     ` Moshe Shemesh
2020-07-29 20:57       ` Jakub Kicinski
2020-07-30 12:08         ` Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 10/13] net/mlx5: Add devlink param enable_remote_dev_reset support Moshe Shemesh
2020-07-28  0:59   ` Jakub Kicinski
2020-07-27 11:02 ` [PATCH net-next RFC 11/13] net/mlx5: Add support for fw live patch event Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 12/13] net/mlx5: Add support for devlink reload level live patch Moshe Shemesh
2020-07-27 11:02 ` [PATCH net-next RFC 13/13] devlink: Add Documentation/networking/devlink/devlink-reload.rst Moshe Shemesh
2020-07-28  5:25 ` [PATCH net-next RFC 00/13] Add devlink reload level option Vasundhara Volam
2020-07-28 16:43   ` Jacob Keller
2020-08-03 10:24     ` Vasundhara Volam
2020-08-03 12:17       ` Moshe Shemesh
2020-08-03 12:47         ` Vasundhara Volam
2020-08-03 13:52           ` Moshe Shemesh
2020-08-04 10:13             ` Vasundhara Volam
2020-08-05  6:32               ` Moshe Shemesh
2020-08-05  6:55                 ` Vasundhara Volam
2020-08-05  8:20                   ` Moshe Shemesh
2020-08-12  9:34                     ` Vasundhara Volam
2020-07-28 16:37 ` Jacob Keller

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