Re: [PATCH -v3 7/8] locking: Move smp_cond_load_acquire() and friends into asm-generic/barrier.h

From: Peter Zijlstra
Date: Wed Jun 01 2016 - 08:46:07 EST

On Wed, Jun 01, 2016 at 01:13:33PM +0100, Will Deacon wrote:
> On Wed, Jun 01, 2016 at 02:06:54PM +0200, Peter Zijlstra wrote:

> > Works for me; but that would loose using cmpwait() for
> > !smp_cond_load_acquire() spins, you fine with that?
> >
> > The two conversions in the patch were both !acquire spins.
> Maybe we could go the whole hog and add smp_cond_load_relaxed?

What about say the cmpxchg loops in queued_write_lock_slowpath()
? Would that be something you'd like to use wfe for?

Writing those in smp_cond_load_{acquire,relaxed)() is somewhat possible
but quite ugleh.