Re: [PATCH] i386 spinlocks should use the full 32 bits, not only 8bits

[Linus Torvalds]

On Tue, 11 Oct 2005, Eric Dumazet wrote:
>
> As NR_CPUS might be > 128, and every spining CPU decrements the lock, we need
> to use more than 8 bits for a spinlock. The current (i386/x86_64)
> implementations have a (theorical) bug in this area.

I don't think there are any x86 machines with > 128 CPU's right now.

The advantage of the byte lock is that a "movb $0" is three bytes shorter 
than a "movl $0". And that's the unlock sequence.

		Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/