* "As many tasks as possible" is limited by (i) the parallelism level
* permitted and (ii) the invariant that a node shall be part of at most one
* rebalancing task at a time (as either stealer or donor).
*/
private synchronized void scheduleMoreTasks() {
RebalanceTask scheduledTask = scheduleNextTask();
while(scheduledTask != null) {
scheduledTask = scheduleNextTask();
}
}