Re: [discuss] Re: x86_64: 2.6.14-rc4 swiotlb broken

From: Ravikiran G Thirumalai
Date: Tue Oct 18 2005 - 13:52:11 EST


On Tue, Oct 18, 2005 at 07:09:03PM +0900, Yasunori Goto wrote:
>
> I tested your patch, but unfortunately, it doesn't work IA64.
> alloc_bootmem_node() requires bigger area than MAX_DMA_ADDRESS.
> It is defined as 4GB for ia64. (arch/ia64/mm/init.c)
> But this patch require smaller area than 4GB.
> So they are exclusive each other.

No, alloc_bootmem_node should work for 4G allocations too; So my approach
should work unless there was some other bootmem request served out of that
node earlier. Btw, the default is to allocate 64MB for swiotlb.
Do you modify that for your boxes? IMHO, we should stick to fixing the
stock kernel now for 2.6.14.

However, IS_LOWPAGES macro in my patch enforces that iotlb start and end
locations to be within 4G. I can change that to within and upto 4G, and the
patch should work for you too.

Thanks,
Kiran
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