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    SubjectRe: MSEC_TO_JIFFIES is messed up...

    * Davide Libenzi <davidel@xmailserver.org> wrote:

    > > why is it wrong?
    >
    > For HZ == 1000 it's fine, even if it'd better to explicitly make it HZ
    > dependent and let the compiler to discard them.

    the compiler cannot discard the multiplication and the division from the
    following:

    x * 1000 / 1000

    due to overflows. But we know that HZ is 1000 in the arch-dependent
    param.h, and in sched.c we use the HZ dependent variant:

    #ifndef JIFFIES_TO_MSEC
    # define JIFFIES_TO_MSEC(x) ((x) * 1000 / HZ)
    #endif
    #ifndef MSEC_TO_JIFFIES
    # define MSEC_TO_JIFFIES(x) ((x) * HZ / 1000)
    #endif

    Ingo
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