Re: [PATCH 0/24] make atomic_read() behave consistently across all architectures

[Paul Mackerras <paulus@samba.org>]

Christoph Lameter writes:

> A volatile default would disable optimizations for atomic_read. 
> atomic_read without volatile would allow for full optimization by the 
> compiler. Seems that this is what one wants in many cases.

Name one such case.

An atomic_read should do a load from memory.  If the programmer puts
an atomic_read() in the code then the compiler should emit a load for
it, not re-use a value returned by a previous atomic_read.  I do not
believe it would ever be useful for the compiler to collapse two
atomic_read statements into a single load.

Paul.
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