Re: [PATCH v5 5/8] mm: HUGE_VMAP arch support cleanup

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 21/08/2020 à 12:39, Nicholas Piggin a écrit :
> Excerpts from Christophe Leroy's message of August 21, 2020 3:40 pm:
>>
>>
>> Le 21/08/2020 à 06:44, Nicholas Piggin a écrit :
>>> This changes the awkward approach where architectures provide init
>>> functions to determine which levels they can provide large mappings for,
>>> to one where the arch is queried for each call.
>>>
>>> This removes code and indirection, and allows constant-folding of dead
>>> code for unsupported levels.
>>
>> I think that in order to allow constant-folding of dead code for
>> unsupported levels, you must define arch_vmap_xxx_supported() as static
>> inline in a .h
>>
>> If you have them in .c files, you'll get calls to tiny functions that
>> will always return false, but will still be called and dead code won't
>> be eliminated. And performance wise, that's probably not optimal either.
> 
> Yeah that's true actually, I think I didn't find a good place to add
> the prototypes in the arch code but I'll have another look and either
> rewrite the changelog or remove it. Although this does get a step closer
> at least.
> 

linux/vmalloc.h includes asm/vmalloc.h
Should it go there ?

Christophe