Re: [PATCH] PM / EM: postpone creating the debugfs dir till fs_initcall

[Lukasz Luba]

On 3/23/21 6:55 PM, Rafael J. Wysocki wrote:
> On Tue, Mar 23, 2021 at 4:57 PM Lukasz Luba <lukasz.luba@xxxxxxx> wrote:
> > On 3/23/21 3:26 PM, Greg KH wrote:
> > > On Tue, Mar 23, 2021 at 02:56:08PM +0000, Lukasz Luba wrote:
> > > > The debugfs directory '/sys/kernel/debug/energy_model' is needed before
> > > > the Energy Model registration can happen. With the recent change in
> > > > debugfs subsystem it's not allowed to create this directory at early stage
> > > > (core_initcall). Thus creating this directory would fail.
> > > > Postpone the creation of the EM debug dir to later stage: fs_initcall.
> > > > It should be safe since all clients: CPUFreq drivers, Devfreq drivers will
> > > > be initialized in later stages.
> > > > The custom debug log below prints the time of creation the EM debug dir at
> > > > fs_initcall and successful registration of EMs at later stages.
> > > >
> > > > [    1.505717] energy_model: creating rootdir
> > > > [    3.698307] cpu cpu0: EM: created perf domain
> > > > [    3.709022] cpu cpu1: EM: created perf domain
> > > >
> > > > fixes: 56348560d495 ("debugfs: do not attempt to create a new file before the filesystem is initalized")
> > > > Reported-by: Ionela Voinescu <ionela.voinescu@xxxxxxx>
> > > > Signed-off-by: Lukasz Luba <lukasz.luba@xxxxxxx>
> > > > ---
> > > > Hi Rafael,
> > > >
> > > > Please take this patch into your PM v5.12 fixes. The change described in
> > > > the patch above landed in v5.12-rc1. Some of our EAS/EM tests are failing.
> > >
> > > Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> >
> > Thank you Greg!
>
> Applied as 5.12-rc material, thanks!

Thank you Rafael!

Regards,
Lukasz