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    SubjectRe: [PATCH] might_sleep() improvements
    Nick Piggin wrote:
    > >Andrew - I thought this might be appropriate for -mm kernels.
    > >
    > >This patch makes the following improvements to might_sleep():
    > >
    > >o Add a "might_sleep_if()" macro for when we might sleep only if some
    > > condition is met. I think this is a bit better than the currently used
    > > "if (cond) might_sleep();" since it's clearer that the test won't be
    > > compiled in if spinlock sleep debugging is turned off. (Obviously
    > > gcc is smart enough to omit simple conditions in that case) It also
    > > looks cleaner, IMO. Think of it as analogous to BUG()/BUG_ON().
    > >
    > I think these should be pushed down to where the sleeping
    > actually happens if possible.

    No, you want to generate the warning as early as possible in case the
    sleeping case happens very infrequently. For instance:

    newskb = skb_unshare(skb, GFP_KERNEL);

    might not even need to do any allocation (much less a sleep) in 99.9% of
    cases, but it's still a bug if it's called in atomic context and we want
    spinlock sleep debugging to catch that for us.

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      Last update: 2005-03-22 13:48    [W:0.030 / U:1.696 seconds]
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