ghalliday/HPCC-Platform — comment on commit 899da5737923877bb131da2f255d2507d0ef98a0
File: roxie/roxiemem/roxiemem.cpp line 727
By rengolin:

My point is that, if the head moves back and forth, and ends up in the same place, and you haven't incremented, you'd get conflicts. But I guess the counters will be incremented elsewhere (so that's not an issue).

The "effect" I was referring to is that ```5 == 6``` and ```5 == 7``` yields the same result.

About the size, ```atomic_t->counter``` is an integer: ```typedef struct { volatile int counter; } atomic_t;``` (so, likely 32-bit). I believe the RBLOCKS_CAS_TAG_MASK mask will sign-extend and give you plenty of counter space.