Messages in this thread | | | Date | Tue, 20 Nov 2018 10:20:10 +0100 | From | Christoph Hellwig <> | Subject | Re: [PATCH RFC] dma-direct: do not allocate a single page from CMA area |
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On Mon, Nov 05, 2018 at 02:40:51PM -0800, Nicolin Chen wrote: > > > In general, this seems to make sense to me. It does represent a theoretical > > > change in behaviour for devices which have their own CMA area somewhere > > > other than kernel memory, and only ever make non-atomic allocations, but > > > I'm not sure whether that's a realistic or common enough case to really > > > worry about. > > > > Yes, I think we should make the decision in dma_alloc_from_contiguous > > based on having a per-dev CMA area or not. There is a lot of cruft in > > It seems that cma_alloc() already has a CMA area check? Would it > be duplicated to have a similar one in dma_alloc_from_contiguous?
It isn't duplicate if it serves a different purpose.
> > this area that should be cleaned up while we're at it, like always > > falling back to the normal page allocator if there is no CMA area or > > nothing suitable found in dma_alloc_from_contiguous instead of > > having to duplicate all that in the caller. > > Am I supposed to clean up things that's mentioned above by moving > the fallback allocator into dma_alloc_from_contiguous, or to just > move my change (the count check) into dma_alloc_from_contiguous? > > I understand that'd be great to have a cleanup, yet feel it could > be done separately as this patch isn't really a cleanup change.
I can take care of any cleanups. I've been trying to dust up that area anyway.
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