Managing memory in a computer system

Patent metadata

Field	Value
Publication number	US-2016328319-A1
Application number	US-201615211275-A
Country	US
Kind code	A1
Filing date	Jul 15, 2016
Priority date	May 15, 2012
Publication date	Nov 10, 2016
Grant date	—

Abstract

Methods, computer program products, and systems for managing memory in a computer system in which memory locations in use at any given time are represented as a set of memory objects in a first object graph. The first object graph includes a system root object associated by references to each of the memory objects. A method includes creating a second root object for the memory so as to form a second object graph for the memory. The method also includes, in response to the dereferencing of a first object from the first object graph, associating the dereferenced first object with the second object graph so that the second object graph includes at least one dereferenced object.

First claim

What is claimed is:

1 . A computer program product for managing memory in a computer system in which memory locations in use at any given time are represented as a set of memory objects in a first object graph that includes a system root object associated by references to each of said memory objects, the computer program product comprising:
a computer-readable storage medium having computer-readable program code embodied therewith, the computer-readable program code executable by a processor to cause the processor to perform a method comprising: creating a second root object for said memory so as to form a second object graph for said memory; and in response to a dereferencing of a first object from said first object graph, associating said dereferenced first object with said second object graph so that said second object graph comprises one or more dereferenced objects.

2 . The computer program product of claim 1 , wherein the method performed by the processor further comprises:
identifying a second object in said first object graph that referenced said first object immediately prior to the dereferencing of said first object; and creating a reference from said second object graph to said second object so as to associate said first object in said second object graph with said second object in said first object graph.

3 . The computer program product of claim 2 , wherein the method performed by the processor further comprises:
creating a first metadata object in said second object graph, said first metadata object being arranged to provide said reference from said second object graph to said second object in said first object graph and to reference said first object in said second object graph.

4 . The computer program product of claim 1 , wherein the method performed by the processor further comprises:
identifying predetermined metadata for said first object that identifies the location of said first object in said first object graph immediately prior to said dereferencing; and storing said metadata in said second object graph in association with said first object.

5 . The computer program product of claim 4 , wherein said metadata is stored in a second metadata object associated with said first object in said second object graph.

6 . The computer program product of claim 4 , wherein said metadata comprises data identifying a field in said second object used to reference said first object immediately prior to said dereferencing of said first object from said second object.

7 . The computer program product of claim 1 , wherein the method performed by the processor further comprises:
in response to a first stage of garbage collection in which a first set of objects comprising all objects present in said first object graph are identified, identifying a second set of objects comprising objects present in said second object graph and not present in said first object graph; and saving predetermined data associated with each of said objects in said second set of objects prior to any further stage of garbage collection in which said second set of objects is deleted from said memory.

8 . The computer program product of claim 7 , wherein said predetermined data comprises data identifying said first object.

9 . The computer program product of claim 7 , wherein said predetermined data comprises data identifying said second object that referenced said first object immediately prior to the dereferencing of said first object.

10 . The computer program product of claim 7 , wherein said predetermined data comprises data identifying the field in said second object that referenced said first object in said first object graph immediately prior to said dereferencing.

Assignees

• IBM

Inventors

• Slattery Edward J

Classifications

• G06F12/0253 Primary

  Garbage collection, i.e. reclamation of unreferenced memory · CPC title

• G06F2212/1044

  Space efficiency improvement · CPC title

• G06F12/023

  Free address space management · CPC title

• G06F16/901

  Indexing; Data structures therefor; Storage structures (for retrieval from the web G06F16/951) · CPC title

• G06F16/9024

  Graphs; Linked lists (G06F16/9027 takes precedence) · CPC title