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Date: Mon, 22 Mar 2004 13:34:41 +0100
From: Andrea Arcangeli <andrea@suse.de>
Subject: Re: can device drivers return non-ram via vm_ops->nopage?
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On Mon, Mar 22, 2004 at 12:05:37PM +0000, Russell King wrote:
> However, it isn't useful for the PCI device-side buffer case, which would
> need to be handled via remap_page_range().

one could allocate page_t for the PCI device-side buffer case too (with
discontigmem to avoid a terrible waste), but it would still be a small
waste. So for non-ram it's better you always map all ptes during ->mmap
and you avoid the page faults like with remap_file_pages than to
allocate a page_t for non-ram ranges with discontigmem.