5 Dec
2011
5 Dec
'11
11:44 a.m.
Looking at this:
#ifndef atomic_inc_unless_negative static inline int atomic_inc_unless_negative(atomic_t *p) { int v, v1; for (v = 0; v >= 0; v = v1) { v1 = atomic_cmpxchg(p, v, v + 1); if (likely(v1 == v)) return 1; } return 0; } #endif
why is it optimised for '*p' being zero?? I'd have though the initial assignment to 'v' should be made by reading '*p' without any memory barriers (etc).
David