Re: [PATCH V2 16/19] csky: SMP support

[Peter Zijlstra]

On Fri, Jul 06, 2018 at 02:07:40PM +0800, Guo Ren wrote:

> > Please explain those mb()'s... I'm thinking you meant to use smp_mb().
> Yes, smp_mb(). Current smp_mb()&mb() is the same: sync.is.
> 
> In next version patch, I'll seperate smp_mb() and mb() and use ld/st.barrier
> instead of sync.is. Sync.is is expensive that it flush cpu's pipeline.

I'll second my own call for documentation, because now there's three
memory ordering instructions:

 "SYNC", "SYNC.IS" and "LD/ST.BARRIER"

None of which have yet been explained.