On Tue, Feb 26, 2019 at 10:33 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > Arguably we could fix that for __this_cpu_xchg(), which isn't IRQ-safe. Yeah, I guess x86 _should_ really do __this_cpu_xchg() as just a read-write pair. In general, a read-write pair is probably always the right thing to do, and the only reason we can't just do it in an architecture-independent way is that we'd want to avoid doing the address generation twice (for architectures where that is an issue). Linus