Linus Torvalds <[EMAIL PROTECTED]> wrote: > The rules are, afaik, that reads can pass buffered writes, BUT WRITES > CANNOT PASS READS (aka "writes to memory are always carried out in program > order").
So in the example I gave, a read after the spin_unlock() may actually get executed before the store in the spin_unlock(), but a read before the unlock will not get executed after. > No. Issuing a read barrier on one CPU will do absolutely _nothing_ on the > other CPU. Well, I think you mean will guarantee absolutely _nothing_ on the other CPU for the Linux kernel. According to the IBM powerpc book I have, it does actually do something on the other CPUs, though it doesn't say exactly what. Anyway, thanks. I'll write up some documentation on barriers for inclusion in the kernel. David - To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
