Re: [PATCH v4 00/16] Prepare slab for memdescs

[Vlastimil Babka <vbabka@suse.cz>]

On 11/13/25 01:09, Matthew Wilcox (Oracle) wrote:
> When we separate struct folio, struct page and struct slab from each
> other, converting to folios then to slabs will be nonsense.  It made
> sense under the 'folio is just a head page' interpretation, but with
> full separation, page_folio() will return NULL for a page which belongs
> to a slab.
> 
> This patch series removes almost all mentions of folio from slab.
> There are a few folio_test_slab() invocations left around the tree that
> I haven't decided how to handle yet.  We're not yet quite at the point
> of separately allocating struct slab, but that's what I'll be working
> on next.
> 
> v4:
>  - Rebased on next-20251110 + a couple of fixes
>  - Fixed compilation warnings when CONFIG_MEMCG not set
>  - Picked up R-b tags from Harry (thanks!)
>  - Restored the order of slab vs large_kmalloc tests (Vlastimil)
>  - Removed setting of LargeKmalloc on tail pages (Vlastimil)
>  - Restored handling of non-slab, non-kmalloc checks in
>    check_heap_object() (me)

All LGTM now. Added to slab/for-next, thanks!

Vlastimil

> Matthew Wilcox (Oracle) (16):
>   slab: Reimplement page_slab()
>   slab: Remove folio references from __ksize()
>   slab: Remove folio references in memcg_slab_post_charge()
>   slab: Remove folio references in slab alloc/free
>   slab: Remove folio references from ___kmalloc_large_node()
>   slab: Remove folio references from free_large_kmalloc()
>   slab: Remove folio references from kvfree_rcu_cb()
>   slab: Remove folio references from kfree()
>   slab: Remove folio references from __do_krealloc()
>   slab: Remove folio references from build_detached_freelist()
>   slab: Remove folio references from kfree_rcu_sheaf()
>   slab: Remove folio references from kfree_nolock()
>   usercopy: Remove folio references from check_heap_object()
>   memcg: Convert mem_cgroup_from_obj_folio() to
>     mem_cgroup_from_obj_slab()
>   kasan: Remove references to folio in __kasan_mempool_poison_object()
>   slab: Remove references to folios from virt_to_slab()
> 
>  include/linux/page-flags.h |  16 +----
>  mm/kasan/common.c          |  12 ++--
>  mm/kfence/core.c           |  14 ++--
>  mm/memcontrol.c            |  36 ++++------
>  mm/slab.h                  |  58 ++++++++--------
>  mm/slab_common.c           |  29 ++++----
>  mm/slub.c                  | 137 +++++++++++++++++++------------------
>  mm/usercopy.c              |  24 ++++---
>  8 files changed, 153 insertions(+), 173 deletions(-)
>