presto-main/src/main/java/io/prestosql/execution/MemoryRevokingScheduler.java/MemoryRevokingScheduler/requestMemoryRevoking
class MemoryRevokingScheduler:    private void requestMemoryRevoking(MemoryPool memoryPool, Collection<SqlTask> sqlTasks)
    {
        long remainingBytesToRevoke = (long) (-memoryPool.getFreeBytes() + (memoryPool.getMaxBytes() * (1.0 - memoryRevokingTarget)));
        remainingBytesToRevoke -= getMemoryAlreadyBeingRevoked(sqlTasks, memoryPool);
        requestRevoking(memoryPool, sqlTasks, remainingBytesToRevoke);
    }