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    SubjectRe: [PATCH] Remove 8 bytes from struct page on 64bit archs

    Hi Bill,

    > Very true. I devised something to address this that appears to work on
    > multiple architectures already by folding ->zone into ->flags, which
    > could be useful. (Dave Jones recommended I just let arch maintainers
    > for things other than i386 mess with page_address() for other arches.)
    > OTOH, I'm more interested in getting it trimmed down than getting credit.

    For archs that need ->zone, merging it with ->flags sounds like a
    great idea. Id like to cram something into ->flags on 64 bit archs
    since its only a long due to bitop constraints. I had thought of
    stuffing ->count in the high word but now Im just getting silly
    since all non atomic accesses to ->flags would then have to be word
    ones.

    > My i386 version, which makes ->virtual conditional on CONFIG_HIGHMEM as
    > well, is at:

    Id like to do redo some profiling, on ppc64 we had page_address() doing
    pointer arithmetic (instead of page->virtual) and the compiler created
    an awful sequence of instructions in the acenic interrupt handler.
    A zero copy TCP benchmark made it rather obvious.

    Anton
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