Re: [PATCH 00/20] arch atomic 'cleanup'

[Will Deacon <will.deacon@arm.com>]

On Wed, Sep 24, 2014 at 07:06:23PM +0100, Peter Zijlstra wrote:
> On Wed, Sep 24, 2014 at 05:54:06PM +0100, Will Deacon wrote:
> > On Thu, May 08, 2014 at 02:58:40PM +0100, Peter Zijlstra wrote:
> > > This series continues the arch atomic rework started with the smp_mb__
> > > interface cleanup.
> > > 
> > > In this series we (mostly) reduce the atomic implementations by eliminating
> > > repetition through use of CPP macros.
> > > 
> > > A future series will use these macros to implement more atomic ops. With these
> > > macros we can end up with more atomic ops while the total LoC still shrinks.
> > > 
> > > Furthermore, rewrite the asm-generic/atomic implementations to require less and
> > > provide more.
> > > 
> > > This series is compile tested on a number of archs, but only boot tested on
> > > x86_64.
> > 
> > What's the status on this series? I'm currently fleshing out an extension to
> > the atomic API that allows more flexible acquire/release semantics and it
> > doesn't make sense for me to copy-paste a bunch of code when I could build
> > it on top of this instead.
> 
> Its in tip/locking/arch and I suppose its headed for the next merge
> window.

Cracking, thanks for that.

> > Also, do you have any other patches pending in this area? I've lost track...
> 
> I do, I have (hopefully) one more series sweeping all archs introducing:
> atomic_{or,and,xor,nand}() and then a few patches killing
> atomic_{set,clear}_mask(). I just need to find time to write changelogs
> and compile test them..
> 
> After that I need to go write that gcc-ll/sc proposal so we can pretend
> to do generic composite atomic ops in C.
> 
> Oh, and like you pointed out, we need to do an audit of the barrier
> semantics on some of our atomic functions like add_unless etc.
> 
> In other word, plenty to keep entertained.

Yup. If you need a hand, please shout and we can probably divide some of
this between us.

Cheers,

Will