presto-main/src/main/java/io/prestosql/operator/TaskContext.java/TaskContext/getFullGcCount
class TaskContext:    public int getFullGcCount()
    {
        long startFullGcCount = this.startFullGcCount.get();
        if (startFullGcCount < 0) {
            return 0;
        }

        long endFullGcCount = this.endFullGcCount.get();
        if (endFullGcCount <= 0) {
            endFullGcCount = gcMonitor.getMajorGcCount();
        }
        return toIntExact(max(0, endFullGcCount - startFullGcCount));
    }