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Subject: Re: [PATCH] Profile likely/unlikely macros
From: Daniel Walker <dwalker@mvista.com>
To: Andrew Morton <akpm@osdl.org>
Cc: linux-kernel@vger.kernel.org, hzhong@gmail.com
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	 <20060424200657.0af43d6a.akpm@osdl.org>
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Date: Mon, 24 Apr 2006 20:17:25 -0700
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On Mon, 2006-04-24 at 20:06 -0700, Andrew Morton wrote:
> Daniel Walker <dwalker@mvista.com> wrote:
> >
> >  +	if (likeliness->type & LIKELY_UNSEEN) {
> >  +		if (atomic_dec_and_test(&likely_lock)) {
> >  +			if (likeliness->type & LIKELY_UNSEEN) {
> >  +				likeliness->type &= (~LIKELY_UNSEEN);
> >  +				likeliness->next = likeliness_head;
> >  +				likeliness_head = likeliness;
> >  +			}
> >  +		}
> >  +		atomic_inc(&likely_lock);
> 
> hm, good enough I guess.  It does need a comment explaining why we
> don't just do spin_lock().
> 
> It'd be a bit saner to do
> 
> 	if (!test_and_set_bit(&foo, 0)) {
> 		...
> 		clear_bit(&foo, 0);
> 	}

Ok .. Also a mistaken "define" in the compiler.h .. I'll fix that as
well ..


Daniel