Sun Microsystems, Inc.

Oracle America, Inc.

John W Coomes

Antonios Printezis

Alexander T Garthwaite

David L Detlefs

Peter B Kessler

David P Stoutamire

Jon A Masamitsu

Y Srinivas Ramakrisha

A technique for establishing a dense prefix for a memory in a computer system. Memory is divided into a plurality of chunks. An efficiency factor is generated for each chunk in one or more chunks contained in the plurality of chunks. The efficiency factor may be based on an amount of memory to be reclaimed, an amount of memory to be scanned and an amount of memory to be copied relative to the chunk. A dense prefix is then established for the memory based on an efficiency factor associated with a chunk.

Dense prefix generation for garbage collection

A heap may be marked and compacted while performing only two passes over the objects and object references in the heap. Specifically, objects and object references are traversed once during a marking phase and again during a compaction phase of split-reference, two-pass mark-compaction. Object references are updated in two steps. First, during marking, each object reference may be updated to include the relative offset within its block of the referenced object and-during compaction that offset may be added to the block's destination address resulting in a reference that points to the actual post-compaction location for the referenced object. Objects of a particular block may be rearranged, or permuted, with respect to each other within the block. However, the order between groups of objects in different blocks may be preserved across compaction.

Split-reference, two-pass mark-compaction

Growing community of inventors

Felton, CA, United States of America

John W Coomes