On 2/18/26 18:14, Eric Chanudet wrote:
> The cma dma-buf heaps let userspace allocate buffers in CMA regions
> without enforcing limits. Since each cma region registers in dmem,
> charge against it when allocating a buffer in a cma heap.
>
> Signed-off-by: Eric Chanudet <[email protected]>
> ---
> drivers/dma-buf/heaps/cma_heap.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma-buf/heaps/cma_heap.c
> b/drivers/dma-buf/heaps/cma_heap.c
> index
> 49cc45fb42dd7200c3c14384bcfdbe85323454b1..bbd4f9495808da19256d97bd6a4dca3e1b0a30a0
> 100644
> --- a/drivers/dma-buf/heaps/cma_heap.c
> +++ b/drivers/dma-buf/heaps/cma_heap.c
> @@ -27,6 +27,7 @@
> #include <linux/scatterlist.h>
> #include <linux/slab.h>
> #include <linux/vmalloc.h>
> +#include <linux/cgroup_dmem.h>
>
> #define DEFAULT_CMA_NAME "default_cma_region"
>
> @@ -58,6 +59,7 @@ struct cma_heap_buffer {
> pgoff_t pagecount;
> int vmap_cnt;
> void *vaddr;
> + struct dmem_cgroup_pool_state *pool;
> };
>
> struct dma_heap_attachment {
> @@ -276,6 +278,7 @@ static void cma_heap_dma_buf_release(struct dma_buf
> *dmabuf)
> kfree(buffer->pages);
> /* release memory */
> cma_release(cma_heap->cma, buffer->cma_pages, buffer->pagecount);
> + dmem_cgroup_uncharge(buffer->pool, buffer->len);
> kfree(buffer);
> }
>
> @@ -319,9 +322,17 @@ static struct dma_buf *cma_heap_allocate(struct dma_heap
> *heap,
> if (align > CONFIG_CMA_ALIGNMENT)
> align = CONFIG_CMA_ALIGNMENT;
>
> + if (mem_accounting) {
Since mem_accounting is a module parameter it is possible to make it changeable
during runtime.
IIRC it currently is read only, but maybe add a one line comment that the cma
heap now depends on that.
Apart from that the series looks totally sane to me.
Regards,
Christian.
> + ret = dmem_cgroup_try_charge(
> + cma_get_dmem_cgroup_region(cma_heap->cma), size,
> + &buffer->pool, NULL);
> + if (ret)
> + goto free_buffer;
> + }
> +
> cma_pages = cma_alloc(cma_heap->cma, pagecount, align, false);
> if (!cma_pages)
> - goto free_buffer;
> + goto uncharge_cgroup;
>
> /* Clear the cma pages */
> if (PageHighMem(cma_pages)) {
> @@ -376,6 +387,8 @@ static struct dma_buf *cma_heap_allocate(struct dma_heap
> *heap,
> kfree(buffer->pages);
> free_cma:
> cma_release(cma_heap->cma, cma_pages, pagecount);
> +uncharge_cgroup:
> + dmem_cgroup_uncharge(buffer->pool, size);
> free_buffer:
> kfree(buffer);
>
>
