Re: [PATCH -v5][RFC]: mutex: implement adaptive spinning

[Ingo Molnar]

* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> 			/*
> 			 * Even if the access succeeded (likely case),
> 			 * the cpu field may no longer be valid. FIXME:
> 			 * this needs to validate that we can do a
> 			 * get_cpu() and that we have the percpu area.

s/get_cpu/cpu_rq ?

> 			 */
> 			if (cpu >= NR_CPUS)
> 				break;
> 
> 			if (!cpu_online(cpu))
> 				break;

Regarding the FIXME, this should be safe already - at least on x86 we set 
up all the possible-cpus-mask per CPU areas during bootup. So any CPU that 
is online, will have a percpu area. (even in the most racy case)

	Ingo
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