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    SubjectRe: Pls apply this spinlock patch to the kernel
    On Mon, Oct 29, 2001 at 09:32:52AM -0800, Linus Torvalds wrote:
    > On Mon, 29 Oct 2001, Alan Cox wrote:
    > > spinlock_t pagecache_lock ____cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED;
    > > cache_line_pad;
    > >
    > > where cache_line_pad is an asm(".align") - I would assume that is
    > > sufficient - Linus ?

    The "cache_line_pad" is useless. The __attribute__((aligned(N)))
    is completely sufficient.

    > Gcc won't guarantee that it puts different variables adjacently - the
    > linker (or even the compiler) can move things around to make them fit
    > better. Which is why it would be better to use the separate section trick.

    Separate sections are also not needed. While you can't guarantee
    adjacency, the object file *does* record the required alignment
    and that must be honored by the linker.

    Now, separate sections do make sense for minimizing accumulated
    padding, but that is a separate issue.

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