Real time, concurrent garbage collection system and method
US5088036A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 17, 1989 |
| Grant date | Feb 11, 1992 |
| Priority date | — |
| Expiry date | Jan 17, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99957
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A real-time, concurrent garbage collection system and method uses the virtual-memory page protection mechanisms of a standard computer system to collect used storage space in a heap. The heap is divided into old-space and new-space portions, each of which is further divided into a multiplicity of pages. At least one mutator thread modifies and adds objects to new-space. Two garbage collection process threads are used: a fault processing thread, and a concurrent scanning thread, both of which help to collect the accessible objects in old-space. The garbage collector initially copies only the root objects, or a portion of the root objects, to new-space. In addition, all pages of new-space which contain copies of old-space objects are initially marked as being protected. Whenever the mutator tries to access an object in a protected page, a page-access trap is generated. The fault processing thread of the garbage collector responds to the trap by scanning the objects in the referenced page, copying old-space object and forwarding pointers as necessary. Then it unprotects the page and resumes the mutator at the faulting instruction. The concurrent scanning thread of the garbage collecto…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.