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    SubjectRe: mm question
    >>> > I was hoping for something more elegant, but I am not adverse to writing
    >>> > my own get_free_page_from_range().
    >>>
    >>> Thats not a trivial task.
    >>
    >> Better than giving up.. Unfortunately looking around in
    >> linux/Documentation and drivers did not yield much in terms of
    >> explanation. I know I can use mem_map_reserve to reserve a page but I
    >> don't know how to get page struct from a physical address nor which lock
    >> to use when messing with this.
    >
    > If you don't have any ISA DMA going on in the system, you might consider
    > bastardising the ZONE_DMA page range by moving the boundary up to
    > 64Mb, then fixing the allocator not to fail back ZONE_NORMAL et al
    > allocations to ZONE_DMA. Thus what was originally ZONE_DMA becomes
    > a sort of ZONE_NO_DMA. Not in the slightest bit pretty, but it might be easier
    > to implement. Depends if you ever want it to get back into the main tree,
    > I guess ;-)

    Of course, if you just did that, you'd never use the ZONE_DMA memory, so
    that's pretty pointless ;-) You need to create an alloc call with an *option*
    to force alloc out of ZONE_NORMAL, not make no fallback the default.

    M.

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