Messages in this thread | | | Date | Wed, 30 Sep 2009 22:58:08 +0200 | From | Ingo Molnar <> | Subject | Re: [tip:sched/urgent] x86: Provide an alternative() based cmpxchg64() |
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* tip-bot for Arjan van de Ven <arjan@infradead.org> wrote:
> Commit-ID: e87aaa7b6d80474ec07a2d2be3f50ef574ffe36c > Gitweb: http://git.kernel.org/tip/e87aaa7b6d80474ec07a2d2be3f50ef574ffe36c > Author: Arjan van de Ven <arjan@infradead.org> > AuthorDate: Wed, 30 Sep 2009 17:07:54 +0200 > Committer: Ingo Molnar <mingo@elte.hu> > CommitDate: Wed, 30 Sep 2009 22:35:44 +0200 > > x86: Provide an alternative() based cmpxchg64() > > cmpxchg64() today generates, to quote Linus, "barf bag" code. > > cmpxchg64() is about to get used in the scheduler to a bug there, > but it's a prerequisite that cmpxchg64() first be made non-sucking. > > This patch turns cmpxchg64() into an efficient implementation that > uses the alternative() mechanism to just use the raw instruction on > all modern systens
The changelog above has 3 typos so i fixed that. The push will generate the hopefully-final version of these patches.
Note, i slightly updated Linus's version of the old-CPU emu code with Eric's micro-optimization.
Ingo
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