atomic64_add_negative
#define local64_add_negative(i, l) atomic64_add_negative((i), (&(l)->a))
WARN_ONCE(atomic64_add_negative(-amount, &cg->res[type].usage),
WARN_ON_ONCE(atomic64_add_negative(-num, &pids->counter));
return atomic64_add_negative(i, v);