Garbage collection without fine-grain synchronization

Details Garbage collection without fine-grain synchronization Garbage collection without fine-grain synchronization

1997-12-10

2000-04-18

Nguyen, Hiep T

Data processing: database and file management or data structures

Database design

Data structure types

711171, 711173, 711147, 711168, 711162, 707204, G06F 1202

Patent

active

060526998

ABSTRACT:
A garbage collection technique for the concurrent operation of a mutator and garbage collector (e.g., marker and sweeper) without requiring fine-grain synchronization or atomicity amongst the mutator, marker and sweeper. The garbage collector employs three threads for concurrently executing the mutator, marker and sweeper, and operates through a series of so called epochs (i.e., individual garbage collection cycles) wherein each epoch (1) runs the mutator; (2) marks all objects that were reachable (i.e., allocated) in the previous epoch with the present epoch's color; and (3) reclaims any objects marked as garbage. Significantly, the object coloring scheme used in the garbage collector eliminates the need for fine-grain synchronization or atomicity by maintaining the invariant that the mutator never sees an object colored with the sweeper's color. Further, only the marker may alter an object's color during an epoch further eliminating the need for fine-grain synchronization or atomicity between the mutator, marker and sweeper.

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