Re: [PATCH] slab: remove the SLUB_DEBUG functionality and config option

[Lorenzo Stoakes (Oracle)]

On Wed, Apr 01, 2026 at 12:59:29PM +0200, Vlastimil Babka (SUSE) wrote:
> The boot-time enabled per-cache debugging has served us well in the
> past, but it's time for it to go, for the following reasons.
>
> - It's a debugging feature. However, thanks to the advent of LLM-based
>   reviews, we are not adding bugs to the kernel anymore, so it's
>   unnecessary now.
>
> - KASAN is more powerful anyway for the classes of bugs that SLUB_DEBUG
>   can catch. But I suspect KASAN is likely to be removed soon too, see
>   above.
>
> - SLAB never had no such dynamic debugging functionality. With the
>   introduction of sheaves percpu caching, we have turned SLUB back into
>   SLAB partially, so this just follows that direction.
>
> - It's removing ~2500 lines of code and I want to keep my overal
>   diffstats negative. This adds a nice margin.

Honestly you're making me look bad because mine is so 'positive' (I SWEAR IT IS
TEST CODE AND COMMENTS) so this turns me against this patch...

>
> Since the slub kunit test depends on SLUB_DEBUG, remove it too. It's not
> a big loss, see the first point above.
>
> Singed-off-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>
> ---
> Signed-off-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>

...but because you're removing clearly useless and superceded debug code (I mean
hello, we have people using openclaw to automate all this unnecessary kernel dev
stuff):

Reviewed-by: claude-opus-4-6[1m]
Assisted-by: Lorenzo Stokes (as per the register) <ljs@xxxxxxxxxx>

Cheers, Claude