Re: [PATCH v4 2/2] arm64: support batched/deferred tlb shootdown during page reclamation

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On 9/21/22 14:13, Yicong Yang wrote:

+static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm)
+{
+	/* for small systems with small number of CPUs, TLB shootdown is cheap */
+	if (num_online_cpus() <= 4)

It would be great to have some more inputs from others, whether 4 (which should
to be codified into a macro e.g ARM64_NR_CPU_DEFERRED_TLB, or something similar)
is optimal for an wide range of arm64 platforms.

+		return false;> +
+#ifdef CONFIG_ARM64_WORKAROUND_REPEAT_TLBI
+	if (unlikely(this_cpu_has_cap(ARM64_WORKAROUND_REPEAT_TLBI)))
+		return false;
+#endif
+
+	return true;
+}
+

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