Re: [RFC PATCH 1/2] percpu: do not put btf_type_tag on per-cpu variable declarations

[Vineet Gupta <vineet.gupta@linux.dev>]

On 11/13/26 11:58 AM, Chris Down wrote:
> Hi Vineet,
>
> Vineet Gupta <vineet.gupta@linux.dev> writes:
>> The message is confusing: this is a declaration, not a definition. But
>> the compiler is right to object to a type tag on the aggregate, and the
>> issue is fundamental: every variant of an aggregate shares one DIE, so
>> there is nowhere to put it. clang drops it silently and GCC warns.
> Not a big deal, but the definition in GCC's message is the definition of
> struct cpuinfo_x86, not of cpu_info. It's saying the attribute is being
> applied to the struct type after the struct was already defined, which is
> accurate. So maybe just drop that first sentence?

Oops, thanks for catching that. I misread which definition it meant. 
Dropping the first sentence in v2.

> I've tested this with clang 23 and GCC 16. With clang, the same 280 types
> and 3360 bytes of BTF go away. Likewise, with GCC, the per-cpu
> declarations no longer warn, and the non-enclosed address space errors
> are gone.

Thanks for verifying, with both the compilers.

> Once the commit message nits are fixed, please feel free to add:
>
> Reviewed-by: Chris Down <chris@chrisdown.name>
> Tested-by: Chris Down <chris@chrisdown.name>

Awesome, I'll add these in v2

Thx,
-Vineet