Better placement of objects reachable from special objects during collection based on the train algorithm

A computer system that includes memory and comprises:

• A) processor circuitry operable to execute processor instructions;
• B) memory circuitry, to which the processor circuitry is responsive, that contains processor instructions readable by the processor circuitry to configure the computer system as a garbage collector that collects the generation in accordance with the train algorithm in collection increments, with which respective collection sets in the generation are associated, by, in at least some of the collection increments:
• i) determining, for each reference that refers to a referred-to object in the collection set and is contained by a containing object located in the generation but outside the collection set, whether that reference satisfies a predetermined set of at least one relay criterion;
• ii) if that reference satisfies the predetermined set of at least one relay criterion, evacuating the referred-to object to a train that is younger than that reference's train and contains a reference to the containing object;
• iii) if that reference does not satisfy the predetermined set of at least one relay criterion, evacuating the referred-to object to that reference's train;
• and
• iv) reclaiming the collection set.

A storage medium containing instructions readable by a computer system including memory to configure the computer system to operate as a garbage collector that:

• A) treats a generation in the memory as divided into car sections organized into trains that have an oldest-to-youngest order;
• and
• B) collects the generation in accordance with the train algorithm in collection increments, with which respective collection sets in the generation are associated, by, in at least some of the collection increments:
• i) determining, for each reference that refers to a referred-to object in the collection set and is contained by a containing object located in the generation but outside the collection set, whether that reference satisfies a predetermined set of at least one relay criterion;
• ii) if that reference satisfies the predetermined set of at least one relay criterion, evacuating the referred-to object to a train that is younger than that reference's train and contains a reference to the containing object;
• iii) if that reference does not satisfy the predetermined set of at least one relay criterion, evacuating the referred-to object to that reference's train;
• and
• iv) reclaiming the collection set.

A garbage collector operating in the memory of a computer and including:

• A) means for treating a generation in a computer system's memory as divided into car sections organized into trains that have an oldest-to-youngest order;
• and
• B) means for collecting the generation in accordance with the train algorithm collection increments, with which respective collection sets in the generation, are associated, by, in at least some of the collection increments:
• i) determining, for each reference that refers to a referred-to object in the collection set and is contained by a containing object located in the generation but outside the collection set, whether that reference satisfies a predetermined set of at least one relay criterion;
• ii) if that reference satisfies the predetermined set of at least one relay criterion, evacuating the referred-to object to a train that is younger than that reference's train and contains a reference to the containing object;
• iii) if that reference does not satisfy the predetermined set of at least one relay criterion, evacuating the referred-to object to that reference's train;
• and
• iv) reclaiming the collection set.