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    SubjectRe: [PATCH] fs/locks.c: prepare for BKL removal
    On Sat, Sep 18, 2010 at 03:09:31PM +0200, Arnd Bergmann wrote:
    > This prepares the removal of the big kernel lock from the
    > file locking code. We still use the BKL as long as fs/lockd
    > uses it and ceph might sleep, but we can flip the definition
    > to a private spinlock as soon as that's done.
    > All users outside of fs/lockd get converted to use
    > lock_flocks() instead of lock_kernel() where appropriate.
    > Based on an earlier patch to use a spinlock from Matthew
    > Wilcox, who has attempted this a few times before. An even
    > earlier attempt to use a semaphore instead of the BKL
    > apparently was made by Andrew Morton about ten years ago,
    > but reverted for performance reasons.

    Actually, I attempted the semaphore conversion ten years ago, but Andrew
    Morton reverted it due to the performance regression. I believe it was
    Apache, when it was using file locks to synchronise between threads.

    Patch looks good; Acked-by: Matthew Wilcox <>

    Matthew Wilcox Intel Open Source Technology Centre
    "Bill, look, we understand that you're interested in selling us this
    operating system, but compare it to ours. We can't possibly take such
    a retrograde step."

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      Last update: 2010-09-18 15:51    [W:0.055 / U:24.140 seconds]
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