Messages in this thread | | | Date | Mon, 27 May 2019 11:15:34 +0200 | From | Peter Zijlstra <> | Subject | Re: [RFC PATCH 3/6] smp: Run functions concurrently in smp_call_function_many() |
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> + /* > + * Choose the most efficient way to send an IPI. Note that the > + * number of CPUs might be zero due to concurrent changes to the > + * provided mask or cpu_online_mask. > + */
Since we have preemption disabled here, I don't think online mask can shrink, cpu-offline uses stop_machine().
> + if (nr_cpus == 1) > + arch_send_call_function_single_ipi(last_cpu); > + else if (likely(nr_cpus > 1)) > + arch_send_call_function_ipi_mask(cfd->cpumask_ipi); > + }
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