Messages in this thread | | | Date | Tue, 2 Sep 2003 01:32:56 -0700 | From | Mitchell Blank Jr <> | Subject | Re: [PATCH] might_sleep() improvements |
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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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