Re: mlockall and mmap of IO devices don't mix

David S. Miller
2003-10-04T05:47:39Z

On Fri, 3 Oct 2003 17:27:27 -0700
Andrew Morton <akpm@osdl.org> wrote:

> Maybe it's best to not overload VM_RESERVED in this manner, but to always
> mark /dev/mem as VM_IO.

Just in cast is isn't clear, it should be defined that anything
that sets VM_IO on an mmap() area should prefill the page tables
as a side effect of such a mmap() request.

Then things like mlockall() have simple semantics on VM_IO area, they
end up being a nop.