Messages in this thread |  | | | Date | Mon, 28 May 2012 10:19:39 +0200 | | From | Marek Szyprowski <> | | Subject | RE: [PATCHv2 3/4] mm: vmalloc: add VM_DMA flag to indicate areas used by dma-mapping framework |
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Hello,
On Sunday, May 27, 2012 2:35 PM KOSAKI Motohiro wrote:
> On Thu, May 24, 2012 at 8:28 AM, Paul Mundt <lethal@linux-sh.org> wrote: > > On Thu, May 24, 2012 at 02:26:12PM +0200, Marek Szyprowski wrote: > >> On Tuesday, May 22, 2012 9:08 AM Minchan Kim wrote: > >> > Hmm, VM_DMA would become generic flag? > >> > AFAIU, maybe VM_DMA would be used only on ARM arch. > >> > >> Right now yes, it will be used only on ARM architecture, but maybe other architecture will > >> start using it once it is available. > >> > > There's very little about the code in question that is ARM-specific to > > begin with. I plan to adopt similar changes on SH once the work has > > settled one way or the other, so we'll probably use the VMA flag there, > > too. > > I don't think VM_DMA is good idea because x86_64 has two dma zones. x86 unaware > patches make no sense.
I see no problems to add VM_DMA64 later if x86_64 starts using vmalloc areas for creating kernel mappings for the dma buffers (I assume that there are 2 dma zones: one 32bit and one 64bit). Right now x86 and x86_64 don't use vmalloc areas for dma buffers, so I hardly see how this patch can be considered as 'x86 unaware'.
Best regards -- Marek Szyprowski Samsung Poland R&D Center
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