Re: [PATCH] O16int for interactivity

Timothy Miller
2003-08-18T19:32:52Z

Nick Piggin wrote:

>> If another task exists at a higher priority, then it gets run at
>> that point.
>
>
>
> Well loosely, yes. Actually, it happens if the task exists and is
> "running",
> and has timeslice left.

> That only happens in scheduler_tick when the
> current
> task has finished its timeslice and the priority arrays are about to be
> switched.

What only happens then?

I'm confused again. Are you talking about swapping the active and
expired arrays?

Of course, all bets are off if the current task actually uses up it
whole timeslice. Then it's not being preempted in quite the same way.

So, then, if there are not tasks left in the active array, naturally,
the highest priority task from what was once the expired array will be
run, and that may be of higher priority.

Is that what you're saying?

> The required conditions for preemption can also occur when a task
> is being woken up, (after sleeping or newly forked).

This is the case that I was thinking of. No swapping of queues. It's
just that a higher priority task was sleeping (or not existing) which
could cause the current task to be preempted before its timeslice ends.