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 echanude@redhat.com

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);