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

From: Arnd Bergmann
Date: Wed Jun 22 2011 - 09:39:56 EST

On Wednesday 22 June 2011, Marek Szyprowski wrote:
> Sounds really good, but it might be really hard to implemnt, at least for
> CMA, because it needs to tweak parameters of memory management internal
> structures very early, when buddy allocator has not been activated yet.

Why that? I would expect you can do the same that hugepages (used to) do
and just attempt high-order allocations. If they succeed, you can add them
as a CMA region and free them again, into the movable set of pages, otherwise
you just fail the request from user space when the memory is already

> > These essentially fight over the same memory (though things are slightly
> > different with dynamic hugepages), and they all face the same basic problem
> > of getting as much for themselves without starving the other three.
> I'm not sure we can solve all such issues in the first version. Maybe we should
> first have each of the above fully working in mainline separately and then
> start the integration works.

Yes, makes sense. We just need to be careful not to introduce user-visible
interfaces that we cannot change any more in the process.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at