in cec.c [142:159]
static void do_spring_cleaning(struct ce_array *ca)
{
int i;
for (i = 0; i < ca->n; i++) {
u8 decay = DECAY(ca->array[i]);
if (!decay)
continue;
decay--;
ca->array[i] &= ~(DECAY_MASK << COUNT_BITS);
ca->array[i] |= (decay << COUNT_BITS);
}
ca->decay_count = 0;
ca->decays_done++;
}