Messages in this thread | | | Date | Mon, 10 Mar 2014 16:42:36 +0100 | From | Peter Zijlstra <> | Subject | [RFC][PATCH 0/7] locking: qspinlock |
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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?
The patches apply to tip/master + lkml.kernel.org/r/20140210195820.834693028@infradead.org
I've yet to look at the paravirt stuff.
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