Re: slablru for 2.5.32-mm1

[Robert Love <rml@tech9.net>]

On Fri, 2002-09-06 at 00:07, Craig Kulesa wrote:

> I have a terribly naive question to add though.  From the original message 
> in this thread, Andrew reverted this BUG_ON due to side-effects:
> 
> 	BUG_ON(smp_call_function(func, arg, 1, 1));
> 
> I must be dense -- why?  All we are doing is passing gcc the hint that
> this is an unlikely path, and surely that's true?  I mean, if it's not, 
> don't we have other things to worry about?

It is just good practice, because it is feasible that one day someone
will do something like:

	#ifdef CONFIG_NO_ASSERT
	#define BUG_ON()		do { } while(0)
	#else
	#define BUG_ON(condition)	do { \
		if (unlikely((condition)!=0)) BUG(); \
	} while(0)
	#endif

so if your BUG_ON has a side effect (e.g. is a function we _have_ to
call, then it needs to be of the normal if..BUG() form.  Note, sure, it
should still be marked unlikely).

	Robert Love


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