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    SubjectRe: Getting big areas of memory, in 2.3.x?
    Alan Cox writes:
    > > That is not the case for loadable (modular) drivers. Loading st
    > > as a module, for example, after boot time sometimes works and sometimes does
    > > not, especially if you set the maximum buffer size larger (to, say, 128K,
    > > as is needed on some drives for good space efficiency).
    >
    > Dont mix up crap code with crap hardware. Scsi generic had similar problems
    > and has been fixed. There are very very few non scatter-gather scsi controllers

    I only mentioned st as example of the inability to get a large page
    long after system startup. Large pages are good for a variety of purposes.
    For example, large pages for programs with large code or data footprints
    can dramatically reduce TLB misses. If the I/O system learns to do direct
    I/O, the overhead of setting up large I/O operations, whether for disk I/O
    or for OpenGL operations such as writing a large image to the screen
    (via DMA), is much reduced when the I/O is done from large pages.
    The CPU overhead of setting up I/O operations is pretty minimal when you
    are doing file I/O to and from a single IDE disk, but far from minimal
    for higher-bandwidth targets, such as a graphics controller or a
    HDTV camera.


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