Re: [PATCH v5 2/6] mm/slab: Plumb kmem_buckets into __do_kmalloc_node()

[Kees Cook <kees@kernel.org>]

On Thu, Jun 20, 2024 at 03:37:31PM +0200, Vlastimil Babka wrote:
> On 6/20/24 3:08 PM, Vlastimil Babka wrote:
> > On 6/19/24 9:33 PM, Kees Cook wrote:
> > I was wondering why I don't see the buckets in slabinfo and turns out it was
> > SLAB_MERGE_DEFAULT. It would probably make sense for SLAB_MERGE_DEFAULT to
> > depends on !SLAB_BUCKETS now as the merging defeats the purpose, wdyt?
> 
> Hm I might have been just blind, can see them there now. Anyway it probably
> doesn't make much sense to have SLAB_BUCKETS and/or RANDOM_KMALLOC_CACHES
> together with SLAB_MERGE_DEFAULT?

It's already handled so that the _other_ caches can still be merged if
people want it. See new_kmalloc_cache():

#ifdef CONFIG_RANDOM_KMALLOC_CACHES
        if (type >= KMALLOC_RANDOM_START && type <= KMALLOC_RANDOM_END)
                flags |= SLAB_NO_MERGE;
#endif

-- 
Kees Cook