Re: [PATCH v2 1/3] livepatch: Add "replace" sysfs attribute

[Petr Mladek <pmladek@suse.com>]

On Mon 2024-06-10 09:32:35, Yafang Shao wrote:
> When building a livepatch, a user can set it to be either an atomic replace
> livepatch or a non atomic replace livepatch. However, it is not easy to
> identify whether a livepatch is atomic replace or not until it actually
> replaces some old livepatches. It will be beneficial to show it directly.
>
> A new sysfs interface called 'replace' is introduced in this patch. The
> result after this change is as follows:
> 
>   $ cat /sys/kernel/livepatch/livepatch-non_replace/replace
>   0
> 
>   $ cat /sys/kernel/livepatch/livepatch-replace/replace
>   1

The description is not sufficient. It does not explain why this
information is useful.

The proposed change allows to see the replace flag only when
the livepatch is already installed. But the value does
not have any effect at this point. It has effect only when
the livepatch is being installed.

I would propose something like:

<proposal>
There are situations when it might make sense to combine livepatches
with and without the atomic replace on the same system. For example,
the livepatch without the atomic replace might provide a hotfix
or extra tuning.

Managing livepatches on such systems might be challenging. And the
information which of the installed livepatches do not use the atomic
replace would be useful.

Add new sysfs interface 'replace'. It works as follows:

   $ cat /sys/kernel/livepatch/livepatch-non_replace/replace
   0

   $ cat /sys/kernel/livepatch/livepatch-replace/replace
   1
</proposal>

> Signed-off-by: Yafang Shao <laoar.shao@gmail.com>

Otherwise the change looks good.

With a better description:

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr