[Core] If condition flaw in `worker.IsAvailableForScheduling`

[ofey404]

What happened + What you expected to happen

I noticed a logic flaw at src/ray/raylet/worker.h:

• !GetAssignedTaskId().IsNil() might be GetAssignedTaskId().IsNil().

  bool IsAvailableForScheduling() const {
    return !IsDead()                        // Not dead
           && !GetAssignedTaskId().IsNil()  // No assigned task
           && !IsBlocked()                  // Not blocked
           && GetActorId().IsNil();         // No assigned actor
  }

Worker is available for scheduling, if no task is assigned.

• But !GetAssignedTaskId().IsNil() means assigned task id is not nil, which is not consistent with comment // No assigned task.

IsAvailableForScheduling is only used for resource deadlock detection, in WarnResourceDeadlock, so this flaw might cause subtle bug in resource management.

Versions / Dependencies

• Ray: 1.13.0

Reproduction script

No reproduction script.

Issue Severity

Low: It annoys or frustrates me.

[ofey404]

src/ray/raylet/node_manager.cc

  for (const auto &worker : worker_pool_.GetAllRegisteredWorkers()) {
    if (worker->IsAvailableForScheduling()) {
      // Progress is being made in a task, don't warn.
      resource_deadlock_warned_ = 0;
      return;
    }
  }

Maybe the comment // No assigned task is wrong, but the condition is correct?

// - If there's no available workers for scheduling
// - But if there are still pending tasks waiting for resource acquisition

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