On Wed, Feb 18, 2026 at 6:15 PM Eric Chanudet <[email protected]> wrote: > > 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/[email protected]/ > [2] > https://lore.kernel.org/all/[email protected]/ > > Signed-off-by: Eric Chanudet <[email protected]>
Tested-by: Albert Esteve <[email protected]> I tested the series with a Fedora VM, setting the global user.slice dmem.max value and then trying to allocate buffers of different sizes with DMA_HEAP_IOCTL_ALLOC. Exceeding the max limit results in 'Resource temporarily unavailable' and the allocation fails. BR, Albert > --- > Changes in v2: > - Rebase on Maxime's introduction of dmem to the cma allocator: > > https://lore.kernel.org/all/[email protected]/ > - 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/[email protected] > > --- > 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 <[email protected]> >
