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

[David Woodhouse]

On Tue, 2004-03-23 at 17:59 +0000, Andy Whitcroft wrote:
> 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?

It would be possible. But why? What benefit do we gain from this
pretence?

Just hide it all from the driver with dma_coherent_mmap() and forget
about it. Let the arch deal with it -- the _common_ case will be that we
use nopage for the actual mapping, perhaps. But why mandate it?


-- 
dwmw2

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/