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    SubjectRe: [PATCH v2 01/11] kexec: introduce kexec_ops struct
    >>> On 22.11.12 at 18:37, "H. Peter Anvin" <hpa@zytor.com> wrote:
    > I actually talked to Ian Jackson at LCE, and mentioned among other
    > things the bogosity of requiring a PUD page for three-level paging in
    > Linux -- a bogosity which has spread from Xen into native. It's a page
    > wasted for no good reason, since it only contains 32 bytes worth of
    > data, *inherently*. Furthermore, contrary to popular belief, it is
    > *not* pa page table per se.
    >
    > Ian told me: "I didn't know we did that, and we shouldn't have to."
    > Here we have suffered this overhead for at least six years, ...

    Even the Xen kernel only needs the full page when running on a
    64-bit hypervisor (now that we don't have a 32-bit hypervisor
    anymore, that of course basically means always). But yes, I too
    never liked this enforced over-allocation for native kernels (and
    was surprised that it was allowed in at all).

    Jan



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