Date: Fri, 26 Mar 2004 17:58:29 +0800
From: Hugang <hugang@soulinfo.com>
To: Christoph Hellwig <hch@infradead.org>,
       linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Problem with remap_page_range/mmap
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	<20040326094656.A3812@infradead.org>
Organization: Beijing Soul
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On Fri, 26 Mar 2004 09:46:56 +0000
Christoph Hellwig <hch@infradead.org> wrote:

> On Fri, Mar 26, 2004 at 10:36:19AM +0100, Christian Leber wrote:
> > What would be the good idea? I need at least 8 at least 4MB (2MB are
> > enough for 2.4) big physical memory pieces for DMA, mapped to
> > userspace.
> > 
> > remap_page_range for ia64.
> 
> Put the page structs into an array and return them from ->nopage.  The
> kernel pagefault code will set up the ptes for you.
> 
> Now actually getting 4MB of continguous memory is a different issue..
> 
> I'm surprised you actually managed to get the allocation to succeed.

There is more detailed information about make page usable to user space,
http://www.xml.com/ldd/chapter/book/ch13.html

Hope that's useful.

-- 
Hu Gang / Steve
Linux Registered User 204016
GPG Public Key: http://soulinfo.com/~hugang/hugang.asc
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