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Date: Thu, 30 Jan 2014 19:16:43 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Will Deacon <will.deacon@arm.com>
Cc: Waiman Long <Waiman.Long@hp.com>, Thomas Gleixner <tglx@linutronix.de>,
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Subject: Re: [PATCH v11 0/4] Introducing a queue read/write lock
 implementation
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On Thu, Jan 30, 2014 at 06:11:36PM +0000, Will Deacon wrote:
> On Thu, Jan 30, 2014 at 06:05:33PM +0000, Peter Zijlstra wrote:
> > On Thu, Jan 30, 2014 at 05:52:12PM +0000, Will Deacon wrote:
> > > It would be nice if these were default implementations of the unlock, then
> > > architectures just implement atomic_sub_release how they like.
> > 
> > Yes, I suppose that makes sense. Last time I proposed the primitive
> > nobody yelled at me, so I suppose that means people agree :-)
> 
> If it's useful for these qrwlocks, that's good enough for me!

There's the qspinlock that can also use it.

> Have you looked at the OpenCL atomic intrinsics at all?
> 
>   http://www.khronos.org/registry/cl/sdk/1.2/docs/man/xhtml/atomicFunctions.html
> 
> There's a good chance that they can be implemented efficiently on any
> architectures that care about OpenCL. As you've noticed, composing them
> together can be more efficient on LL/SC-based architectures too.

Never looked at OpenCL, I'll have a look.

> Okey doke. If you need a stable (non-rebasing) branch, just holler.

Nah, who cares about those anyway :-)