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    SubjectRe: [PATCH RFC] pm_qos_requirement might sleep
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    On Thu, 2008-08-14 at 08:52 -0700, mark gross wrote:

    > Keeping a lock around the different "target_value"s may not be so
    > important. Its just a 32bit scaler value, and perhaps we can make it an
    > atomic type? That way we loose the raw_spinlock.

    My suggestion was to keep the locking for the write side - so as to
    avoid stuff stomping on one another, but drop the read side as:

    spin_lock
    foo = var;
    spin_unlock
    return foo;

    is kinda useless, it doesn't actually serialize against the usage of
    foo, that is, once it gets used, var might already have acquired a new
    value.

    The only thing it would protect is reading var, but since that is a
    machine sized read, its atomic anyway (assuming its naturally aligned).

    So no need for atomic_t (its read-side is just a read too), just drop
    the whole lock usage from pq_qos_requirement().





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