Messages in this thread | | | Subject | Re: [PATCH -v7][RFC]: mutex: implement adaptive spinning | From | Peter Zijlstra <> | Date | Thu, 08 Jan 2009 16:30:05 +0100 |
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On Thu, 2009-01-08 at 10:28 -0500, Steven Rostedt wrote: > On Thu, 8 Jan 2009, Peter Zijlstra wrote:
> > in the unlikely case we schedule(), that seems expensive enough to want > > to make the spin case ever so slightly faster. > > OK, that makes sense, but I would comment that. Otherwise, it just looks > like another misuse of the unlikely annotation.
OK, sensible enough.
> > > Should we need to do a "get_cpu" or something? Couldn't the CPU disappear > > > between these two calls. Or does it do a stop-machine and the preempt > > > disable will protect us? > > > > Did you miss the preempt_disable() a bit up? > > No, let me rephrase it better. Does the preempt_disable protect against > another CPU from going off line? Does taking a CPU off line do a > stop_machine?
Yes and yes.
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