From: Moshe Shemesh <moshe@mellanox.com>
To: Jakub Kicinski <kuba@kernel.org>,
Jacob Keller <jacob.e.keller@intel.com>
Cc: Jiri Pirko <jiri@resnulli.us>,
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: Wed, 29 Jul 2020 17:54:08 +0300 [thread overview]
Message-ID: <04f00024-758c-bc19-c187-49847c24a5a4@mellanox.com> (raw)
In-Reply-To: <20200728130653.7ce2f013@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
On 7/28/2020 11:06 PM, Jakub Kicinski wrote:
> On Tue, 28 Jul 2020 12:18:30 -0700 Jacob Keller wrote:
>> On 7/28/2020 11:44 AM, Jakub Kicinski wrote:
>>> 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
>> Where today "driver-param-init" is the default behavior. But didn't we
>> just say that mlxsw also does the equivalent of fw-activate?
> Actually the default should probably be the combination of
> driver-param-init and net-ns-respawn.
What about the support of these combinations, one device needs to reset
fw to apply the param init,
while another device can apply param-init without fw reset, but has to
reload the driver for fw-reset.
So the support per driver will be a matrix of combinations ?
> My expectations would be that the driver must perform the lowest reset
> level possible that satisfies the requested functional change.
> IOW driver may do more, in fact it should be acceptable for the driver
> to always for a full HW reset (unless --live or other constraint is
> specified).
OK, but some combinations may still not be valid for specific driver
even if it tries lowest level possible.
>>> 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]
>> I guess I don't quite see how level fits in? This is orthogonal to the
>> other settings?
> Yup, it is, it's already orthogonal to what reload does today, hence the
> need for the "driver default" hack.
>
>>> 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.
>>>
>> I think I agree, having the "what gets reloaded" as a separate vector
>> makes sense and avoids confusion. For example for ice hardware,
>> "fw-activate" really does mean "Do an EMP reset" rather than just a
>> "device reset" which could be interpreted differently. ice can do
>> function level reset, or core device reset also. Neither of those two
>> resets activates firmware.
>>
>> Additionally the current function load process in ice doesn't support
>> driver-init at all. That's something I'd like to see happen but is quite
>> a significant refactor for how the driver loads. We need to refactor
>> everything out so that devlink is created early on and factor out
>> load/unload into handlers that can be called by the devlink reload. As I
>> have primarily been focused on flash update I sort of left that for the
>> future because it was a huge task to solve.
> Cool! That was what I was concerned about, but I didn't know any
> existing driver already has the problem. "FW reset" is not nearly
> a clear enough operation. We'd end up with drivers differing and
> users having to refer to vendor documentation to find out which
> "reset level" maps to what.
>
> I think the components in ethtool-reset try to address the same
> problem, and they have the notion of per-port, and per-device.
> In the modern world we lack the per-host notion, but that's still
> strictly clearer than the limited API proposed here.
next prev parent reply other threads:[~2020-07-29 14:54 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
2020-07-28 19:18 ` Jacob Keller
2020-07-28 20:06 ` Jakub Kicinski
2020-07-29 14:54 ` Moshe Shemesh [this message]
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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