static volatile long gc_notTooOften_last;
static volatile long gc_notTooOften_interval = 1000;

static void gc_notTooOften() {
  gc_notTooOften_last = fixTimestamp(gc_notTooOften_last);
  if (now() >= gc_notTooOften_last + gc_notTooOften_interval) {
    gc();
    gc_notTooOften_last = now();
  }
}