Re: [PATCH 8/9] RISC-V: User-facing API

From: Will Deacon
Date: Thu Jul 06 2017 - 11:45:57 EST

On Thu, Jul 06, 2017 at 08:34:27AM -0700, Christoph Hellwig wrote:
> On Thu, Jul 06, 2017 at 09:55:03AM +0100, Will Deacon wrote:
> > Agreed on the indirection; it feels like this is something that should be in
> > the vDSO, which could use the cmpxchg instruction if it's available, or
> > otherwise just uses plain loads and stores.
> Even that seems like a lot of indirection for something that is in
> the critical fast path for synchronization. I really can't understand
> how a new ISA / ABI could even come up with an idea as stupid as making
> essential synchronization primitives optional.

No disagreement there!