Messages in this thread | | | Date | Wed, 05 Dec 2012 18:14:20 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: [RFC PATCH 02/10] smp, cpu hotplug: Fix smp_call_function_*() to prevent CPU offline properly |
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On 12/05/2012 05:09 AM, Rusty Russell wrote: > "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> writes: >> From: Michael Wang <wangyun@linux.vnet.ibm.com> >> >> With stop_machine() gone from the CPU offline path, we can't depend on >> preempt_disable() to prevent CPUs from going offline from under us. > > Minor gripe: I'd prefer this paragraph to use the future rather than > past tense, like: "Once stop_machine() is gone ... we won't be able to > depend". >
Fixed in the new version.
> Since you're not supposed to use the _stable() accessors without calling > get_online_cpus_stable_atomic(), why not have > get_online_cpus_stable_atomic() return a pointer to the stable cpumask? > (Which is otherwise static, at least for debug). >
We don't have to worry about this now because the new version doesn't use stable cpumask.
> Might make the patches messier though... > > Oh, and I'd love to see actual benchmarks to make sure we've actually > fixed a problem with this ;) >
Of course :-) They will follow, once we have a proper implementation that we are happy with :-)
Regards, Srivatsa S. Bhat
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