Remembered-set scrubbing to remove stale entries in an incremental garbage collector
AssigneeSun Microsystems, Inc.
InventorAlexander T. Garthwaite
Life of this patent
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Abstract
A computer system, method and software for detecting and purging stale entries from remembered sets associated with incrementally collectible regions used in an incremental garbage collection technique like the Trains algorithm is described. Stale entries are detected by a number of techniques, and then purged, eliminated, or scrubbed. These techniques make use of the summarized information about regions such as cards or incrementally collectible regions that indicate age of allocation, time a region was last scanned, last time an entry was inserted into a remembered set, as well as how far forward or backward objects in a given region refer in a generation.
Claims41
A computer implemented method for eliminating or scrubbing stale entries from remembered sets associated with incrementally collectible regions in an incremental garbage collector, the scrubbing occurring without scanning the regions referred to by the entries, the method comprising the steps of:
- defining stale entries, determining conditions under which stale entries will or are likely to occur, examining those conditions, detecting stale entries without scanning any memory region, and scrubbing the stale entries.
A computer system for eliminating or scrubbing stale entries from remembered sets associated with incrementally collectible regions in an incremental garbage collector, the scrubbing occurring without scanning the regions referred to by the entries, the method comprising:
- means for defining stale entries, means for determining conditions under which stale entries will or are likely to occur, means for examining those conditions, means for detecting stale entries without scanning any memory region, and means for scrubbing the stale entries.
A computer readable media comprising instructions for execution in a processor for implementing an incremental garbage collector that performs the steps of:
- defining stale entries, determining conditions under which stale entries will or are likely to occur, examining those conditions, detecting stale entries without scanning any memory region, and scrubbing the stale entries.
Dependencies are inferred from the claim text.