Re: [PATCH] dma-contiguous: support numa CMA for specified node

[Andrew Morton]

On Mon, 10 Jul 2023 15:49:44 +0800 Yajun Deng <yajun.deng@xxxxxxxxx> wrote:

> The kernel parameter 'cma_pernuma=' only supports reserving the same
> size of CMA area for each node. We need to reserve different sizes of
> CMA area for specified nodes if these devices belong to different nodes.
> 
> Change kernel parameter from 'cma_pernuma=' to 'numa_cma='. If node
> isn't specified, it will reserve CMA area for per-numa node. if the node
> is specified, it will reserve CMA area for the specified node.
> 
> At the same time, print the node id in cma_declare_contiguous_nid() if
> enabled CONFIG_NUMA.

Changing an existing kernel parameter will break existing setups.  It
would be preferable to add a new parameter for this?