Re: [PATCH v2 00/22] Prepare slab for memdescs

[Vlastimil Babka <vbabka@suse.cz>]

On 9/10/25 13:54, 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.
> 
> This has dependencies on both the memdesc_flags_t conversion and the
> sheaves work (as well as textual conflicts with nth_page removal and
> a few other patches).  At this point in the development cycle, I'm not
> pushing for this to be included in the next merge window.

Thanks, I agree that next cycle will be easier. However seems some cleanups
are sufficiently self-contained and small to still be submitted to mm - I
think patches 5 and 22 (any more?), which would reduce conflict potential.
Meanwhile I'll look at 01-04 to consider adding to slab tree immediately also.

> 
> v2:
>  - Rebased on next-20250909
>  - Picked up review tags (thanks!)
>  - Fixed the bug in ksize()
> 
> Matthew Wilcox (Oracle) (22):
>   slab: Remove unnecessary test from alloc_debug_processing()
>   slab: Remove unnecessary test from alloc_single_from_partial()
>   slab: Remove dead code in check_slab()
>   slab: Remove dead code in free_consistency_checks()
>   mm: Constify compound_order() and page_size()
>   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 kvfree()
>   slab: Remove folio references from __do_krealloc()
>   slab: Remove folio references from build_detached_freelist()
>   slab: Remove dead code from free_large_kmalloc()
>   slab: Remove folio references from kfree_rcu_sheaf()
>   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()
>   mm: Remove redundant test in validate_page_before_insert()
> 
>  include/linux/mm.h         |   6 +-
>  include/linux/page-flags.h |  16 +---
>  mm/kasan/common.c          |  12 +--
>  mm/kfence/core.c           |  12 ++-
>  mm/memcontrol.c            |  36 +++-----
>  mm/memory.c                |   3 +-
>  mm/slab.h                  |  58 ++++++-------
>  mm/slab_common.c           |  29 ++++---
>  mm/slub.c                  | 163 +++++++++++++++++--------------------
>  mm/usercopy.c              |  21 +++--
>  10 files changed, 160 insertions(+), 196 deletions(-)
>