Re: [tip:x86/urgent] x86: Add memory modify constraints to xchg() and cmpxchg()

Linus Torvalds
2010-07-28T15:46:24Z

On Tue, Jul 27, 2010 at 10:33 PM, tip-bot for H. Peter Anvin
<hpa@zytor.com> wrote:
>
> x86: Add memory modify constraints to xchg() and cmpxchg()

Ack. I assume this doesn't really change the code generated? At least
not with a gcc that honors the whole memory clobber thing properly?

I also suspect that we can/should get rid of the __xg() thing - it was
there just to make sure gcc didn't see the memory read as a single
word and tried to optimize it. With the "+m" it probably doesn't
matter any more (don't know if it ever did)

Linus