Re: can device drivers return non-ram via vm_ops->nopage?

[Andy Whitcroft]

--On 21 March 2004 23:58 +0000 Russell King <rmk+lkml@xxxxxxxxxxxxxxxx>
wrote:

> On Sun, Mar 21, 2004 at 03:51:31PM -0800, Linus Torvalds wrote:
>> That might be the minimal fix, since it would basically involve:
>>  - change whatever offensive "virt_to_page()" calls into 
>>    "dma_map_to_page()".
>>  - implement "dma_map_to_page()" for all architectures.
>> 
>> Would that make people happy?
> 
> Unfortunately this doesn't make dwmw2 happy - he claims to have machines
> which implement dma_alloc_coherent using RAM which doesn't have any
> struct page associated with it.

Would it not be possible to allocate struct page's for these special areas
of memory?  Worst, worst, worst case could they not represent pages in a
memory only node in the NUMA sense?  I am sure there is some way they could
be 'tacked' onto the end of the cmap in reality?

-apw
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