Messages in this thread |  | | | Date | Sun, 31 Dec 2000 20:07:41 +0200 | | From | Matti Aarnio <> | | Subject | Re: test13-pre5 |
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On Sun, Dec 31, 2000 at 09:27:23AM -0800, Linus Torvalds wrote: > On Sun, 31 Dec 2000, Andi Kleen wrote: > > > > Sounds good. It could also be controlled by a CONFIG_SPACE_EFFICIENT for > > embedded systems, where you could trade a bit of CPU for less memory overhead > > even on systems where u8 is slow and atomicity doesn't come into play > > because it's UP anyways. > > UP has nothing to do with it. > The alpha systems I remember this problem on were all SMP.
Actually nothing SMP specific in that problem sphere. Alpha has load-locked/store-conditional pair for this type of memory accesses to automatically detect, and (conditionally) restart the operation - to form classical ``locked-read-modify-write'' operations.
In what situations the compiler will use those instructions, that I don't know. Volatiles, very least, use them. Will closely packed bytes be processed with it without them being volatiles ? How about bitfields ?
Newer Alphas have byte/short load/store instructions, so things really aren't that straight-forward...
.... > I don't think it's a good diea. > Linus
/Matti Aarnio - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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