Re: [PATCH 1/12]: MUTEX: Implement mutexes

[Linus Torvalds]

On Sat, 17 Dec 2005, David Howells wrote:
> 
> Linux supports a number of those archs. Amongst them are 68000 (TAS), arm (SWP
> I think), i386 (XCHG), and FRV (SWAP). I'm also looking at another that only
> has BSET/BCLR.

Don't bother putting i386 in that list.

Quite frankly, you've done it before, and I think it's intellectually 
totally dishonest.

i386 does semaphores with a "lock decl". You CANNOT DO IT FASTER. I dare 
you. Why the hell do you try to make it sound as if x86 would need this 
new thing, when it absolutely does NOT need it.

Yes, x86 _also_ has an xchg instruction, but hey, that's a total 
non-argument. We don't actually use that. 

Of the other architectures you list, only ARM is really important. And no, 
arm doesn't do swap. It does LL/SC (except they call it "ldrex/strex", 
which I assume stands for "load/store with reservation and X just because 
X is cool. Yeah, we're cool" (*)).

68k is dead. Nobody cares. So just say it outright: this is totally just a 
FRV feature, and NOBODY ELSE IS IN THE LEAST INTERESTED.

Ok? Just to inject a little honesty here.

			Linus

(*) Actually, some arm docs I found implies that "ex" stands for 
"exclusive", but that leaves me wondering what the "r" stands for? 
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