Re: [question] About triggering a region snapshot through the devlink cmd

On 2019/9/27 16:13, Jiri Pirko wrote:

Fri, Sep 27, 2019 at 09:40:47AM CEST, linyunsheng@huawei.com wrote:

quoted

Hi, Jiri & Alex

   It seems that a region' snapshot is only created through the
driver when some error is detected, for example:
mlx4_crdump_collect_fw_health() -> devlink_region_snapshot_create()

   We want to trigger a region' snapshot creation through devlink
cmd, maybe by adding the "devlink region triger", because we want
to check some hardware register/state when the driver or the hardware
does not detect the error sometimes.

Does about "devlink region triger" make sense?

If yes, is there plan to implement it? or any suggestion to implement
it?

Actually, the plan is co convert mlx4 to "devlink health" api. Mlx5
already uses that.

You should look into "devlink health".

Hi Jiri,

I agree, the mlx4 firmware dump stuff should use the devlink health API, as it's for error conditions.

I've recently been investigating using devlink regions to expose non-error regions where it really does make sense to "trigger" a snapshot.

The original region commit message indicates that there were plans to support requesting snapshots, and even potentially writing to the region directly.

I wanted to use a region to expose some set of flash/NVM contents. Being able to request a snapshot is essential in this case. I saw that netdevsim does this through a debugfs hook, but that really doesn't make sense to me for a production driver.

It makes sense to me to be able to trigger a region snapshot directly through devlink. Should I spin up some patches to implement it?

Thanks,
Jake