Messages in this thread | | | Date | Sat, 17 Dec 2005 12:11:39 -0800 (PST) | From | Linus Torvalds <> | Subject | Re: [PATCH 1/12]: MUTEX: Implement mutexes |
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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? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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