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Subject: Re: [LSF/MM TOPIC] Discuss least bad options for resolving
 longterm-GUP usage by RDMA
To:     Christopher Lameter <cl@linux.com>
CC:     Jason Gunthorpe <jgg@ziepe.ca>, Ira Weiny <ira.weiny@intel.com>,
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From:   John Hubbard <jhubbard@nvidia.com>
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On 2/12/19 8:39 AM, Christopher Lameter wrote:
> On Mon, 11 Feb 2019, John Hubbard wrote:
> 
>> But anyway, Jan's proposal a bit earlier today [1] is finally sinking into
>> my head--if we actually go that way, and prevent the caller from setting up
>> a problematic gup pin in the first place, then that may make this point sort
>> of moot.
> 
> Ok well can be document how we think it would work somewhere? Long term
> mapping a page cache page could a problem and we need to explain that
> somewhere.
> 

Yes, once the dust settles, I think Documentation/vm/get_user_pages.rst is the
right place. I started to create that file, but someone observed that my initial
content was entirely backward-looking (described the original problem, instead 
of describing how the new system would work). So I'll use this opportunity for 
a do-over. :)

thanks,
-- 
John Hubbard
NVIDIA