Re: [PATCH v6 14/18] x86: Minimal SLAB alignment

[Maciej Wieczor-Retman]

On 2025-11-10 at 18:48:35 +0100, Alexander Potapenko wrote:
>> diff --git a/arch/x86/include/asm/cache.h b/arch/x86/include/asm/cache.h
>> index 69404eae9983..3232583b5487 100644
>> --- a/arch/x86/include/asm/cache.h
>> +++ b/arch/x86/include/asm/cache.h
>> @@ -21,4 +21,8 @@
>>  #endif
>>  #endif
>>
>> +#ifdef CONFIG_KASAN_SW_TAGS
>> +#define ARCH_SLAB_MINALIGN (1ULL << KASAN_SHADOW_SCALE_SHIFT)
>
>I don't think linux/linkage.h (the only header included here) defines
>KASAN_SHADOW_SCALE_SHIFT, does it?

I revised all the x86 and non-arch places where ARCH_SLAB_MINALIGN is used and
all these places also include linux/slab.h which does include
KASAN_SHADOW_SCALE_SHIFT. So there are no cases where it's undefined.

The minalign makes sense defined here but including kasan headers causes
compilation errors all over the place. And I don't think moving
KASAN_SHADOW_SCALE_SHIFT here makes much sense?