ZS_OBJS_INUSE
class_stat_add(class, ZS_OBJS_INUSE, 1);
class_stat_add(class, ZS_OBJS_INUSE, 1);
class_stat_sub(class, ZS_OBJS_INUSE, 1);
unsigned long obj_used = class_stat_read(class, ZS_OBJS_INUSE);
obj_used = class_stat_read(class, ZS_OBJS_INUSE);