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    SubjectRe: [RFC] i386: Remove page sized slabs for pgds and pmds
    On Wed, 28 Mar 2007 13:12:56 -0700 (PDT)
    Christoph Lameter <clameter@sgi.com> wrote:

    > The benefit of preconstructed pgds and pmds in the i386 arch code seem to
    > be debatable. The performance measurements indicate that there may be a slight
    > benefit but it seems to almost vanish in the noise ratio.

    yeah, I did a couple hours testing with rc5, rc5+quicklists,
    rc5+quicklists+qlhack, where "qlhack" is my patch which removes the
    quicklists and mysteriously causes i386 to crash.

    I was testing 8-way x86_64 with patch-scripts (wildly fork-intensive),
    kernel build and lmbench.

    Basically I was unable to observe any statistically meaningful-looking
    differences between any of them.

    I would like to test qlhack on ia64, because ia64 puts pte-pages into the
    quicklists as well, but my ia64 machine is presently indisposed.

    My (much) preferred way to handle all this is to remove the quicklists from
    all architectures: just use alloc_page() and free_page() for pte pages, pmd
    pages, etc. I remain unaware of any testing whcih indicates that this
    would be a bad change.

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