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

[Lorenzo Stoakes (Oracle)]

On Wed, Apr 01, 2026 at 01:05:34PM +0200, David Hildenbrand (Arm) wrote:
> On 4/1/26 12:59, 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.
>
> Right, and probably LLM review would find many of bugs in the existing
> SLUB_DEBUG code.
>
> >
> > - 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.
>
> Of course.
>
> >
> > - 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.
>
> Personal stats clearly matter more than anything else.
>
> >
> > 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>
> > ---
> >  lib/Kconfig.debug      |   12 -
> >  lib/Kconfig.kasan      |    2 -
> >  lib/tests/Makefile     |    1 -
> >  lib/tests/slub_kunit.c |  329 --------
> >  mm/Kconfig.debug       |   60 --
> >  mm/dmapool.c           |    4 -
> >  mm/memcontrol-v1.c     |   17 -
> >  mm/mempool.c           |  105 ---
> >  mm/slab.h              |   34 -
> >  mm/slub.c              | 2074 +-----------------------------------------------
>
> slab.h vs. slub.c is annoying.
>
> Can you just rename that to sheaf.c / sheaf.h now while at it?

I'd prefer sheav.es.c, but naturally all comments in that file would need to be
translated to Spanish.

>
> --
> Cheers,
>
> David

Cheers, Lorenzo