Creating parallel tasks, how to limit new task creation?

In my program I'm starting parallel tasks one by one (http requests), doing it far ahead of any actual results those tasks can return.

It looks like

while (continueTaskSwarming == true)
{
    Task.Run(() => Task());
}

Of course that way I have way more tasks scheduled than can be processed, so when I cancel them through cancellation token, it takes a lot of time to just cancel them all - they are scheduled after all, so they must actually run before they can be cancelled.

How can I organize task creation so that there always be only limited bunch of tasks ready to run, with new tasks scheduled only when there is some "place" for them? I mean, some "straight" way, something like

while (continueTaskSwarming == true)
{
    PauseUntilScheduledTaskCountIsLowerThan(100);
    Task.Run(() => Task());
}

Is that possible?

EDIT:

The obvious way, I think, is to put all tasks created into some list, removing them on completion and checking count of active/scheduled tasks. But I don't know (and don't know keywords to google it) if I can "remove" task from itself, or from ContinueWith() method. Anyone knows?

---

There are lots of ways to do this. You can protect a counter (of current tasks) with a lock, using Monitor.Wait() to have the task-producing thread wait until the counter is decremented and it's safe to start another task.

Another approach is to use the Semaphore synchronization object. This does basically the same thing, but encapsulated in an easy-to-use object. You create a new Semaphore, specifying how many concurrent threads you want to be able to hold the lock at once. By having each task take a lock on the semaphore, then you can have the task-producer also lock on the semaphore and when you read the max number of tasks, the producer won't be able to continue and create another task until one of the currently running tasks completes.

---

If I understand correctly, you are trying to achieve limited concurrency while executing tasks

this will help you

http://msdn.microsoft.com/en-us/library/ee789351(v=vs.110).aspx

Limited concurrency level task scheduler (with task priority) handling wrapped tasks

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