Re: [Linaro-mm-sig] [PATCH 08/10] mm: cma: Contiguous Memory Allocator added

On Wed, 22 Jun 2011 09:03:30 +0200, Hans Verkuil hverkuil@xs4all.nl wrote:

What I was wondering about is how this patch series changes the allocation in case it can't allocate from the CMA pool. Will it attempt to fall back to a 'normal' allocation?

Unless Marek changed something since I wrote the code, which I doubt, if CMA cannot obtain memory from CMA region, it will fail.

Part of the reason is that CMA lacks the knowledge where to allocate memory from. For instance, with the case of several memory banks, it does not know which memory bank to allocate from.

It is, in my opinion, a task for a higher level functions (read: DMA layer) to try another mechanism if CMA fails.