Hi, The comment for the atomic_fetch_andnot() in nohz_idle_balance() says:
"barrier, pairs with nohz_balance_enter_idle(), ensures ..." which, well, does sound a note of warning... ;-) I see that nohz_balance_enter_idle() has an smp_mb__after_atomic() but the comment for the latter suggests that this barrier is pairing with the smp_mb() in _nohz_idle_balance(). So, what is the intended pairing barrier for the atomic_fetch_andnot()? what (which memory accesses) do you want "to order" here? Thanks, Andrea
