On 11/7/25 4:02 AM, Pasha Tatashin wrote:
On Fri, Nov 7, 2025 at 7:00 AM Pasha Tatashin <[email protected]> wrote:
Hi, Pasha
In our previous discussion, we talked about counting the number of times
the kernel is rebooted via kexec. At that time, you suggested adding a
variable in debugfs to keep track of this count.
However, since debugfs is now optional, where would be an appropriate
place to store this variable?
It is an optional config and can still be enabled if the live update
reboot number value needs to be accessed through debugfs. However,
given that debugfs does not guarantee a stable interface, tooling
should not be built to require these interfaces.
In the WIP LUO [1] I have, I pr_info() the live update number during
boot and also store it in the incoming LUO FDT tree, which can also be
accessed through this optional debugfs interface.
The pr_info message appears like this during boot:
[ 0.000000] luo: Retrieved live update data, liveupdate number: 17
Pasha
Forgot to add link to WIP LUOv5:
[1] https://github.com/soleen/linux/tree/luo/v5rc04
Thanks a lot. I’ve carefully read this commit:
https://github.com/soleen/linux/commit/60205b9a95c319dc9965f119303a1d83f0ff08fa.
To be honest, I’d like to run some tests with who/luo, including the
selftest for kho/luo. Could you please share the steps with me?
If the testing steps have already been documented somewhere, could you
please share the link?
Best Regards,
Yanjun.Zhu
