On Sat, Feb 20, 2021 at 03:17:04PM -0800, Nadav Amit wrote: > + /* > + * 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. > + */ > + 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);
I just ran into conflicts with another patch set, and noticed that the above should probably be: if (nr_cpus == 1) send_call_function_single_ipi(last_cpu); else if (likely(nr_cpus > 1)) arch_send_call_function_ipi_mask(cfd->cpumask_ipi); Which will avoid the IPI when @last_cpu is idle.