Messages in this thread | | | Date | Wed, 2 Oct 2013 18:07:48 +0100 | From | Catalin Marinas <> | Subject | Re: [PATCH v6 10/19] xen: introduce xen_alloc/free_coherent_pages |
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On Wed, Oct 02, 2013 at 06:03:46PM +0100, Stefano Stabellini wrote: > On Tue, 1 Oct 2013, Catalin Marinas wrote: > > On 30 Sep 2013, at 16:31, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote: > > > On Fri, Sep 27, 2013 at 05:09:58PM +0100, Stefano Stabellini wrote: > > >> xen_swiotlb_alloc_coherent needs to allocate a coherent buffer for cpu > > >> and devices. On native x86 and ARMv8 is sufficient to call > > >> __get_free_pages in order to get a coherent buffer, while on ARM we need > > >> to call the native dma_ops->alloc implementation. > > >> > > >> When arm64 stops using the swiotlb by default and starts having multiple > > >> dma_ops implementations, we'll use __get_dma_ops there too. > > > > > > I presume this is a future TODO, not some further patch (in which > > > case you should say in here the title of it). If it is a TODO could > > > you stick that in the sentence here somewhere to make it crytal clear that > > > it is not implemented. > > > > Thanks for pointing this out. The arm64 patch shouldn't be different > > from arm here. I thought a subsequent patch already added > > __get_dma_ops() for arm64. > > Yes, the arm64 patch already added __get_dma_ops. > > However I am not using __get_dma_ops to implement > xen_alloc_coherent_pages for arm64 because I can just use > __get_free_pages for the moment:
So why do the work twice when we'll get coherency maintenance in the DMA ops?
-- Catalin
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