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SubjectRe: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
On Fri, Dec 08, 2006 at 08:06:23AM -0800, Christoph Lameter wrote:
> On Fri, 8 Dec 2006, Russell King wrote:
> > I'm trying to suggest a better implementation for atomic ops rather
> > than just bowing to this x86-centric "cmpxchg is the best, everyone
> > must implement it" mentality.
> cmpxchg is the simplest solution to realize many other atomic operations
> and its widely available on a wide variety of platforms. It is the most
> universal atomic instruction that I know of. Other atomic operations may
> be more efficient but certainly cmpxchg is the most universal.
> Having multiple instructions with restrictions of what can be done in
> between just complicates the use and seems to be arch specific. I have not
> seen a better solution. Are you really advocating the weirdly complex
> ll/sc be adopted by other architectures?

You're advocating cmpxchg is adopted by all architectures. It isn't
available on many architectures, and those which it can be requires
unnecessarily complicated coding.

Russell King
Linux kernel 2.6 ARM Linux -
maintainer of:
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