[PATCH v2 0/3] dma-buf: heaps: cma: enable dmem cgroup accounting

[Eric Chanudet <echanude@redhat.com>]

An earlier series[1] from Maxime introduced dmem to the cma allocator in
an attempt to use it generally for dma-buf. Restart from there and apply
the charge in the narrower context of the CMA dma-buf heap instead.

In line with introducing cgroup to the system heap[2], this behavior is
enabled based on dma_heap.mem_accounting, disabled by default.

dmem is chosen for CMA heaps as it allows limits to be set for each
region backing each heap. The charge is only put in the dma-buf heap for
now as it guaranties it can be accounted against a userspace process
that requested the allocation.

[1] https://lore.kernel.org/all/20250310-dmem-cgroups-v1-0-2984c1bc9312@kernel.org/
[2] https://lore.kernel.org/all/20260116-dmabuf-heap-system-memcg-v3-0-ecc6b62cc446@redhat.com/

Signed-off-by: Eric Chanudet <echanude@redhat.com>
---
Changes in v2:
- Rebase on Maxime's introduction of dmem to the cma allocator:
  https://lore.kernel.org/all/20250310-dmem-cgroups-v1-0-2984c1bc9312@kernel.org/
- Remove the dmem region registration from the cma dma-buf heap
- Remove the misplaced logic for the default region.
- Link to v1: https://lore.kernel.org/r/20260130-dmabuf-heap-cma-dmem-v1-1-3647ea993e99@redhat.com

---
Eric Chanudet (1):
      dma-buf: heaps: cma: charge each cma heap's dmem

Maxime Ripard (2):
      cma: Register dmem region for each cma region
      cma: Provide accessor to cma dmem region

 drivers/dma-buf/heaps/cma_heap.c | 15 ++++++++++++++-
 include/linux/cma.h              |  9 +++++++++
 mm/cma.c                         | 20 +++++++++++++++++++-
 mm/cma.h                         |  3 +++
 4 files changed, 45 insertions(+), 2 deletions(-)
---
base-commit: 948e195dfaa56e48eabda591f97630502ff7e27e
change-id: 20260128-dmabuf-heap-cma-dmem-f4120a2df4a8

Best regards,
-- 
Eric Chanudet <echanude@redhat.com>