Re: [PATCH 00/11] mm/cma: charge cma allocation to memcg using per area counters

On Sun, Aug 23, 2026 at 10:02:35AM +0300, Mike Rapoport wrote:
> Hi Eric,
> 
> On Fri, Aug 21, 2026 at 02:56:52PM -0400, Eric Chanudet wrote:
> > CMA allocations are currently unaccounted for by cgroup memory
> > controllers. As system resources, they should fall under memcg, but CMA
> > areas partition the available space for different purposes and memcg
> > doesn't have a good representation for that.
> > 
> > Add a memory_cma_accounting cgroupfs option in preparation for the
> > following new behavior. Make it disabled by default since it will
> > account for CMA allocations in memcg which may affect existing systems.
> > 
> > Provide CMA charge/uncharge functions to memcg that introduce a CMA area
> > specific counter per CMA area. Charges are issued to memcg and to a page
> > counter for the CMA area used. The allocation's folios are marked with
> > the cgroup via commit_charge() (once for large folios, per-page for
> > 0-order ones) so they can be later uncharged correctly.
> > 
> > Add the new memcg calls into the cma allocator under __cma_alloc_frozen,
> > for both cma and hugetlb_cma allocations accounting.
> > 
> > Finally register the per-area usage counters in the cgroupfs. Each CMA
> > area creates a memory.cma.<area>.{current,max} pair for reporting and
> > limitation for each area.
> > 
> > Selftests and a vmtest script are added to this series for convenience.
> > The tests are simple accounting and limit enforcement verification using
> > the default reserved CMA area (cma=) and hugetlb_cma.
> > 
> > Signed-off-by: Eric Chanudet <[email protected]>
> > ---
> > Eric Chanudet (11):
> >       mm/cma: drop const for struct page on release API
> >       mm/cma: include linux/cma.h in cma.h
> >       cgroup: add memory_cma_accounting mount option
> >       memcg: add cma charge/uncharge functions for area counters
> >       mm/cma: charge cma allocation to memcg per area counters
> >       memcg: register per-area usage counters in cgroupfs
> >       selftests: cgroup: add cma configs for cgroup selftest suite
> >       selftests: cgroup: add memcg cma tests
> >       selftests: cgroup: add a vmtest script for memcg
> >       selftests: cgroup: add memcg hugetlb_cma tests
> >       selftests: cgroup: amend vmtest-memcg to run the hugetlb cma tests
> 
> CI found issues:
>  
> https://github.com/linux-mm/linux-mm/actions/runs/32519133924

Indeed my apologies, I messed up CMA=n it needed a forward declaration
and gating for mm/cma.h content included in mm/memcontrol.c.

I queued this up for a v2, with the other issues reported by Sashiko.

> 
> >  Documentation/admin-guide/cgroup-v2.rst         |  35 +++
> >  include/linux/cgroup-defs.h                     |   5 +
> >  include/linux/cma.h                             |   4 +-
> >  include/linux/memcontrol.h                      |  19 ++
> >  kernel/cgroup/cgroup.c                          |  15 +-
> >  mm/cma.c                                        |  14 +-
> >  mm/cma.h                                        |   6 +
> >  mm/cma_debug.c                                  |   1 -
> >  mm/cma_sysfs.c                                  |   1 -
> >  mm/memcontrol.c                                 | 205 ++++++++++++
> >  tools/testing/selftests/cgroup/.gitignore       |   1 +
> >  tools/testing/selftests/cgroup/Makefile         |   2 +
> >  tools/testing/selftests/cgroup/config           |   5 +
> >  tools/testing/selftests/cgroup/test_cma_memcg.c | 402 ++++++++++++++++++++++++
> >  tools/testing/selftests/cgroup/vmtest-memcg.sh  | 197 ++++++++++++
> >  15 files changed, 903 insertions(+), 9 deletions(-)
> > ---
> > base-commit: 98f21c54f99519329c18e2625b0ea6db14524d09
> > change-id: 20260706-cma-memcg-regions-696cb5ef7998
> > 
> > Best regards,
> > -- 
> > Eric Chanudet <[email protected]>
> > 
> 
> -- 
> Sincerely yours,
> Mike.
> 

-- 
Eric Chanudet