Messages in this thread | | | From | Rusty Russell <> | Subject | Re: [RFC PATCH 02/10] smp, cpu hotplug: Fix smp_call_function_*() to prevent CPU offline properly | Date | Wed, 05 Dec 2012 10:09:22 +1030 |
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"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".
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).
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 ;)
Rusty.
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