Re: [PATCH] mm: alloc_tag: change the KASAN_TAG_WIDTH for HW_TAGS

[Guilherme Giacomo Simoes <trintaeoitogc@gmail.com>]

Andrew Morton <akpm@linux-foundation.org> wrote: 
> > the KASAN_TAG_WIDTH is 8 bits for both (HW_TAGS and SW_TAGS), but for
> > HW_TAGS the KASAN_TAG_WIDTH can be 4 bits bits because due to the design
> > of the MTE the memory words for storing metadata only need 4 bits.
> > Change the preprocessor define KASAN_TAG_WIDTH for check if SW_TAGS is
> > define, so KASAN_TAG_WIDTH should be 8 bits, but if HW_TAGS is define,
> > so KASAN_TAG_WIDTH should be 4 bits.
> 
> Why?
> 
> I assume the effect is to save a few flags bits under some
> circumstances?  But that's just me guessing - please fully describe the
> motivation and effects within changelogs.
Ok, I will change the commit message with the "why", and send a v2.

Thanks.