On Tue, Sep 03, 2019 at 08:44:40AM -0700, Linus Torvalds wrote: > That said, it won't affect any of the core architectures much, because > smp_store_release() isn't that expensive (it's just a compiler barrier > on x86, it's a cheap instruction on arm64, and it should be very cheap > on any other architecture too unless they do insane things - even on > powerpc, which is about the worst case for any barriers, it's just an > lwsync).
Right, x86/s390/Sparc it's a compiler barrier, ARM64 has a store-release op which is relatively cheap, Power has an LWSYNC, but the rest does store-release with smp_mb() -- and this includes ARM.
