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    SubjectRe: [PATCH] Futexes IV (Fast Lightweight Userspace Semaphores)
    Followup to:  <>
    By author: Linus Torvalds <>
    In newsgroup:
    > You don't understand. This has nothing to do with lock holders, or
    > anything else.
    > I'm saying that we map in a page at a magic offset (just above the stack),
    > and that page contains the locking code.
    > For 386 CPU's (where only UP matters), we can trivially come up with a
    > lock that doesn't use cmpxchg8b and that isn't SMP-safe. It might even go
    > into the kernel every time if it has to - ie it _works_, it just isn't
    > optimal.

    Okay, I'll say it and be impopular...

    Perhaps it's time to drop i386 support?

    It seems to me that the i386 support has been around mostly on a
    "until we have a reason to do otherwise" basis, but perhaps this is
    the reason?

    There certainly are enough little, nagging reasons... CMPXCHG, BSWAP,
    and especially WP...

    <> at work, <> in private!
    "Unix gives you enough rope to shoot yourself in the foot." <>
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