Re: [RFC][PATCH 0/7] locking: qspinlock

[Peter Zijlstra]

On Tue, Mar 11, 2014 at 11:45:03AM +0100, Ingo Molnar wrote:
> 
> * Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> 
> > Hi Waiman,
> > 
> > I promised you this series a number of days ago; sorry for the delay 
> > I've been somewhat unwell :/
> > 
> > That said, these few patches start with a (hopefully) simple and 
> > correct form of the queue spinlock, and then gradually build upon 
> > it, explaining each optimization as we go.
> > 
> > Having these optimizations as separate patches helps twofold; 
> > firstly it makes one aware of which exact optimizations were done, 
> > and secondly it allows one to proove or disprove any one step; 
> > seeing how they should be mostly identity transforms.
> > 
> > The resulting code is near to what you posted I think; however it 
> > has one atomic op less in the pending wait-acquire case for NR_CPUS 
> > != huge. It also doesn't do lock stealing; its still perfectly fair 
> > afaict.
> > 
> > Have I missed any tricks from your code?
> 
> Waiman, you indicated in the other thread that these look good to you, 
> right? If so then I can queue them up so that they form a base for 
> further work.

Ah, no that was on the qrwlock; I think we managed to cross wires
somewhere.

I've got this entire pile waiting for something:

  lkml.kernel.org/r/20140210195820.834693028@xxxxxxxxxxxxx

That's 5 mutex patches and the 2 qrwlock patches. Not sure what to do
with them. To merge or not, that is the question.
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