Re: [PATCH v3] sched/topology: Enable topology_span_sane check only for debug builds

K Prateek Nayak
2025-02-11T10:56:50Z

Hello Shrikanth,

On 2/11/2025 11:22 AM, Shrikanth Hegde wrote:
>
> [..snip..]
>>
>> What I'm getting to is that the arch specific topology parsing code
>> can set a "SDTL_ARCH_VERIFIED" flag indicating that the arch specific
>> bits have verified that the cpumasks are either equal or disjoint and
>> since sched_debug() is "false" by default, topology_span_sane() can
>> bail out if:
>>
>>      if (!sched_debug() && (tl->flags & SDTL_ARCH_VERIFIED))
>>          return;
>>
>
> it would simpler to use sched_debug(). no?
>
> Since it can be enabled at runtime by "echo Y > verbose", if one one needs to enable even after boot. Wouldn't that suffice to run topology_span_sane by doing a hotplug?

Ack! It was a suggestion in case folks felt apprehensive about guarding
the check behind sched_debug() ...

>
>> In case arch specific parsing was wrong, "sched_verbose" can always
>> be used to double check the topology and for the arch that require
>> this sanity check, Steve's optimized version of
>> topology_span_sane() can be run to be sure of the sanity.
>>
>> All this justification is in case folks want to keep
>> topology_span_sane() around but if no one cares, Naman and Saurabh's
>> approach works as intended.

... which is why I ended that long explanation with this :)

Valentin seems to be on board with the current approach from Naman and
Saurabh and it works as intended.

>>
>

--
Thanks and Regards,
Prateek