On Tue, Feb 09, 2021 at 02:16:48PM -0800, Nadav Amit wrote:
> + /*
> + * Although we could have used on_each_cpu_cond_mask(),
> + * open-coding it has performance advantages, as it eliminates
> + * the need for indirect calls or retpolines. In addition, it
> + * allows to use a designated cpumask for evaluating the
> + * condition, instead of allocating one.
> + *
> + * This code works under the assumption that there are no nested
> + * TLB flushes, an assumption that is already made in
> + * flush_tlb_mm_range().
> + *
> + * cond_cpumask is logically a stack-local variable, but it is
> + * more efficient to have it off the stack and not to allocate
> + * it on demand. Preemption is disabled and this code is
> + * non-reentrant.
> + */
> + struct cpumask *cond_cpumask = this_cpu_ptr(&flush_tlb_mask);
> + int cpu;
> +
> + cpumask_clear(cond_cpumask);
> +
> + for_each_cpu(cpu, cpumask) {
> + if (tlb_is_not_lazy(cpu))
> + __cpumask_set_cpu(cpu, cond_cpumask);
> + }
> + smp_call_function_many(cond_cpumask, flush_tlb_func, (void
> *)info, 1);
No need for the cast here, which would also avoid the pointlessly
overly long line.
