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    SubjectRe: [PATCH][RFC][0/4] InfiniBand userspace verbs implementation
    On Sun, Apr 24, 2005 at 09:23:48AM -0500, Timur Tabi wrote:
    > Andrew Morton wrote:
    >
    > >If your theory is correct then it should be able to demonstrate this
    > >problem without any special hardware at all: pin some user memory, then
    > >generate memory pressure then check the contents of those pinned pages.
    >
    > I tried that, but I couldn't get it to fail. But that was a while ago, and
    > I've learned a few things since then, so I'll try again.
    >
    > >But if, for the DMA transfer, you're using the array of page*'s which were
    > >originally obtained from get_user_pages() then it's rather hard to see how
    > >the kernel could alter the page's contents.
    > >
    > >Then again, if mlock() fixes it then something's up. Very odd.
    >
    > With mlock(), we don't need to use get_user_pages() at all. Arjan tells me
    > the only time an mlocked page can move is with hot (un)plug of memory, but
    > that isn't supported on the systems that we support.

    You don't "support" i386 or ia64 or x86-64 or ppc64 systems? What
    hardware do you support? And what about the fact that you are aiming to
    get this code into mainline, right? If not, why are you asking here?
    :)

    thanks,

    greg k-h
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