Re: [PATCH v2 00/11] mm: memcontrol: constify the read side of the memcg API

["Lorenzo Stoakes (ARM)" <ljs@kernel.org>]

On Tue, Sep 08, 2026 at 11:57:36AM -0400, Tal Zussman wrote:
> The memcg accessors, lruvec helpers, and stat readers only read from
> the memcg, folio, or lruvec they are given, but take non-const
> pointers. Constify them, along with a couple other helper functions in
> mm/page_counter.c along the way.
>
> This started as a follow-up to [1] that quickly grew in proportions :)
>
> [1]: https://lore.kernel.org/linux-mm/anYqSDnC2BbJXv1h@casper.infradead.org/

:)

I looked through it, all looks sensible, and it compiles locally and
const-ifies things so it's all good AFAIC! So:

Acked-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>

For the whole series :)

>
> ---
> Changes in v2:
> - Patch 3: Constify the folio argument of folio_lruvec_relock_irq() and
>   folio_lruvec_relock_irqsave() as well, per Sashiko
> - Patch 3: Note that mem_cgroup_lruvec() updates lruvec->pgdat in the
>   per-node structure, not the memcg, per Sashiko
> - Patches 3 and 8: Use container_of_const() in lruvec_memcg() and the
>   lruvec_page_state() family, per Sashiko
> - Link to v1: https://patch.msgid.link/20260902-folio_memcg-const-v1-0-e2c1da22246d@columbia.edu
>
> ---
> Tal Zussman (11):
>       mm: memcontrol: take a const folio in folio_memcg() and friends
>       mm: memcontrol: constify obj_cgroup_memcg() and friends
>       mm: memcontrol: constify the lruvec helpers
>       mm/page_io: take a const folio in bio_associate_blkg_from_folio()
>       mm: memcontrol: constify the mem_cgroup accessors
>       mm: page_counter: constify page_counter_read() and page_counter_margin()
>       mm: memcontrol: constify the reclaim protection helpers
>       mm: memcontrol: constify the memcg and lruvec stat readers
>       mm: memcontrol: constify the swap accounting helpers
>       mm: memcontrol: constify mem_cgroup_swappiness() and mem_cgroup_get_max()
>       mm: memcontrol: constify the zswap and socket pressure helpers
>
>  include/linux/memcontrol.h   | 204 ++++++++++++++++++++++---------------------
>  include/linux/mmzone.h       |   2 +-
>  include/linux/page_counter.h |   4 +-
>  include/linux/swap.h         |  12 +--
>  mm/memcontrol.c              |  49 ++++++-----
>  mm/page_counter.c            |   2 +-
>  mm/page_io.c                 |  14 +--
>  mm/swap.h                    |   2 +-
>  8 files changed, 148 insertions(+), 141 deletions(-)
> ---
> base-commit: 9d3243fc689fef444f87e0a703b4c99653137e1b
> change-id: 20260807-folio_memcg-const-4a67e40d485b
>
> Best regards,
> --
> Tal Zussman <tz2294@columbia.edu>
>

--
Cheers, Lorenzo