Messages in this thread | | | Subject | Re: [PATCH] Fix WARN_ON / WARN_ON_ONCE regression | From | Tim Chen <> | Date | Tue, 10 Oct 2006 08:41:46 -0700 |
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On Tue, 2006-10-10 at 09:04 -0400, Steven Rostedt wrote:
> > Holy crap! I wonder where else in the kernel gcc is doing this. (of > course I'm using gcc4 so I don't know). Is there another gcc attribute > to actually tell gcc that a variable is really mostly read only (besides > placing it in a mostly read only elf section)? > > What was wrong with the original WARN_ON_ONCE with > > if (unlikely(condition) && __warn_once) > > This didn't have the cache crash problem too, did it? > I don't have a gcc3 around to test.
In the original WARN_ON_ONCE, gcc3 only writes to __warn_once when (condition) is true. So it does not cause cache bouncing by always writing to __warn_once.
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