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SubjectRe: [PATCH v3 1/9] smp: Run functions concurrently in smp_call_function_many()
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On 7/18/19 5:58 PM, Nadav Amit wrote:
> @@ -624,16 +622,11 @@ EXPORT_SYMBOL(on_each_cpu);
> void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
> void *info, bool wait)
> {
> - int cpu = get_cpu();
> + preempt_disable();
>
> - smp_call_function_many(mask, func, info, wait);
> - if (cpumask_test_cpu(cpu, mask)) {
> - unsigned long flags;
> - local_irq_save(flags);
> - func(info);
> - local_irq_restore(flags);
> - }
> - put_cpu();
> + __smp_call_function_many(mask, func, func, info, wait);
> +
> + preempt_enable();
> }

The get_cpu() was missing it too, but it would be nice to add some
comments about why preempt needs to be off. I was also thinking it
might make sense to do:

cfd = get_cpu_var(cfd_data);
__smp_call_function_many(cfd, ...);
put_cpu_var(cfd_data);

instead of the explicit preempt_enable/disable(), but I don't feel too
strongly about it.

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