Prior art for a GC scheduler with an adaptive free-memory threshold?

Patent: US 8,166,269

Assignee: Oracle

Priority Date: 11/5/09

Prior Art: Search Google Prior Art search for 8,166,269

I’m having trouble figuring out whether Oracle is claiming to have invented the method of an adjustable free-space low-water-mark threshold to trigger garbage collection.

I also observe that they don’t provide a single complete sample algorithm for actually computing this threshold.

Claim 1:

A method of adaptively triggering garbage collection within a computer system, the method comprising:

1. Initializing a data structure to comprise N empty buckets (N>0), wherein each bucket represents an amount of free memory;

2. Periodically recording a rate of allocation of free memory;
   for each of multiple iterations of garbage collection:

   • calculating a mean rate of allocation of free memory prior to the iteration;
   • observing a drop in the free memory during the iteration;
   • reading the data structure to examine a bucket corresponding to the observed memory drop;
   • if the bucket is empty, storing in the bucket the calculated mean rate of allocation of free memory; and
   • if the bucket stores a rate of allocation higher than the calculated mean rate of allocation of free memory, replacing the stored rate of allocation with a new rate of allocation; and
   • if an increase in the rate of allocation of free memory is observed during said periodic recording, adjusting a free memory threshold at which the garbage collection is initiated.

Can someone help me parse this claim?