Re: [patch 04/11] mutex subsystem, add include/asm-x86_64/mutex.h

[Ingo Molnar]

* Eric Dumazet <dada1@xxxxxxxxxxxxx> wrote:

> >+		:"=D" (dummy)						\
> >+		: "D" (v)						\
> >+		: "rax", "rsi", "rdx", "rcx",				\
> >+		  "r8", "r9", "r10", "r11", "memory");			\
> >+} while (0)
> 
> Hi Ingo
> 
> I do think this assembly is not very fair. It has an *insane* register 
> pressure for the compiler : The fast path is thus not so fast.

if you look at the compiler output you'll notice that it's not a problem 
actually: this fastpath is only inlined into the generic code, where it 
has no clobbering side-effects.

you are right in that if this were to be inlined left and right, this 
would be quite bad.

	Ingo
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