Messages in this thread | | | Date | Fri, 20 Apr 2012 21:21:49 +1000 | From | Nick Piggin <> | Subject | Re: [PATCH 3/3] brlocks/lglocks: turn into functions |
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This still not merged?
On Mon, Mar 05, 2012 at 05:35:28PM +1030, Rusty Russell wrote: > From: Andi Kleen <ak@linux.intel.com> > > lglocks and brlocks are currently generated with some complicated macros > in lglock.h. But there's no reason to not just use common utility > functions and put all the data into a common data structure.
There is a reason, which is performance. Extra function call, but also IIRC the percpu accessor was not so fast doing it this way. Maybe that's improved...
So what's the performance difference?
> > Since there are at least two users it makes sense to share this code in a > library. This is also easier maintainable than a macro forest. > > This will also make it later possible to dynamically allocate lglocks and > also use them in modules (this would both still need some additional, but > now straightforward, code)
Yes, but let's not do either of those things :)
I was slightly crazy when committing that patch to the kernel, I'll admit. So if performance isn't significantly affected, then definitely. If it is... well, it's much easier to gain 1% performance by maintaining 100 self contained lines of hilarious code like this than to actually use your brain to improve somewhere else!
Thanks, Nick
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