[lkml]   [2007]   [Jul]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: [PATCH 6/8] i386: bitops: Don't mark memory as clobbered unnecessarily
    Hi Andi,

    On Mon, 23 Jul 2007, Andi Kleen wrote:

    > On Monday 23 July 2007 18:05:58 Satyam Sharma wrote:
    > > From: Satyam Sharma <>
    > >
    > > [6/8] i386: bitops: Don't mark memory as clobbered unnecessarily
    > >
    > > The goal is to let gcc generate good, beautiful, optimized code.
    > The first goal is correct code.
    > The reason for the memory barrier is to prevent other memory references
    > from being moved over the atomic reference.
    > e.g. when a bit is used to communicate with another CPU this might be dangerous.

    Yes, but _that_ address (of the bit-string) is protected already -- by the
    implicit memory barrier due to the LOCK prefix. We shouldn't really be
    caring about any other memory addresses, so it doesn't affect the
    correctness of the bitops API at all.

    [ and at least the __test_and_change_bit() case is definitely okay. ]

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2007-07-23 18:27    [W:0.026 / U:0.168 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site