Re: [PATCH v3 03/14] sched/core: uclamp: add CPU's clamp groups accounting

Dietmar Eggemann
2018-08-15T11:00:02Z

On 08/15/2018 12:54 PM, Patrick Bellasi wrote:
> On 15-Aug 11:37, Dietmar Eggemann wrote:
>> On 08/14/2018 06:49 PM, Patrick Bellasi wrote:
>>> Hi Dietmar!
>>>
>>> On 14-Aug 17:44, Dietmar Eggemann wrote:
>>>> On 08/06/2018 06:39 PM, Patrick Bellasi wrote:

[..]

>> If this is only for testing/debugging, I would suggest a simple one line
>> BUG_ON()
>
> These are (eventually) considered as recoverable errors... thus,
> AFAIK, using BUG_ON is overkilling and discouraged:
> https://elixir.bootlin.com/linux/latest/source/include/asm-generic/bug.h#L42

Not sure about that. If this refcounting is out of sync, that's
indicating a serious issue here for me which should be fixed.

>> You find CONFIG_SCHED_DEBUG=y in production kernels as well.
>
> AFAIK, that setting is discouraged for production kernels...
> Moreover, it's still better to WARN sometimes on a production kernel
> the crash the device, isnt't it?

IMHO, if this is something which should not happen at all, a BUG_ON() is
the right thing to do here. And you get the call stack to investigate
why it hit.