[...] 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; > +} > + [...]