Re: Scheduling Memory in Viengoos

At Sat, 28 Jun 2008 06:52:49 +0200,
<[email protected]> wrote:
> 
> On Thu, Jun 26, 2008 at 03:24:59PM +0200, Neal H. Walfield wrote:
> 
> >   A.available = MAX (A.share + unused, A.allocated) * A.pressure
> > 
> > (If unused is non-zero then pressure is 1)
> 
> So when there is memory pressure in the system, then the "available"
> memory of a task drops below its "share"?...

Pressure is calculated locally.  When an activity exceeds its share
and must yield some memory (as other activities want their share), its
pressure is increased (and A.pressure logically decreases).  If
A.allocated < A.share, then A.pressure is 1.

A principal's share is dynamic.  First, principals enter and exit the
system and this can affect an activity's share.  Second, a
high-priority activity, by allocating memory, can decrease the share
of a low-priority activity.