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SubjectRe: test13-pre5
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
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