Mark-sweep, Operating System

Assignment Help:

The objects that a program can access directly are those objects which are referenced by local vari-ables on the processor stack, or by any global/static variables that refer to objects, or by variables in CPU registers. In the context of garbage collection, these variables are called the roots. An object is indirectly accessible if it is referenced by a ?eld in some other (directly or indirectly) accessible object. An accessible object is said to be live. Conversely, an object which is not live is garbage.

Note that heap objects which are live are indirectly accessible from the roots or other heap objects. The idea of mark-sweep is relatively straightforward. We start at the roots, and recursively visit every object accessible through pointers, marking them as live. At the end of the process, every thing not marked is considered garbage and will be deleted. Notice that mark-sweep can perform lazy garbage collection, in the sense that it does not necessarily need to remove the garbage immediately.

Note thatmark-sweep does not clean upmemory which is allocated, but simply never used. Also, periodically we have to visit all objects recursively, starting from the roots. For a large program, this will be slow. This is a problem with the traditional mark-sweep algorithm.


Related Discussions:- Mark-sweep

Analysis of Pseudocode Sempahore Solution, Gopher Gallery consists of a sho...

Gopher Gallery consists of a shopping mall and a cart ride that covers the 150 acre habitat. There are m visitors and n single-person vehicles. Visitors stroll around the mall at

Explain the request/response interface, Explain the Request/Response Interf...

Explain the Request/Response Interface   Many issues are involved in providing a procedural interface for client functions to interact with server components. First off, since

Explain page traffic, The term ‘page traffic’ explains   Page traffic’...

The term ‘page traffic’ explains   Page traffic’ explains the movement of pages in and out of memory.

Write in brief on unix file structure, Write in brief on UNIX file structur...

Write in brief on UNIX file structure. UNIX considers every file to be a sequence of 8-bit bytes no interpretation of these bits is made by the operating system. This system pr

Why page sizes always powers of 2, Q. Why page sizes always powers of 2? ...

Q. Why page sizes always powers of 2? Answer: Recall that paging is executed by breaking up an address into a page and offset number. It is most competent to break the address

Define the term system software, Question: (a) Define the term system ...

Question: (a) Define the term system software and application software, giving an example for each. (b) Draw a diagram to represent the abstract view of a computer system i

Blocking locks, We have talked about blocking locks, which voluntarily yiel...

We have talked about blocking locks, which voluntarily yield, and spinlocks, which just spin until they acquire the lock. At ?rst, it seems like spinlocks are verywasteful, and tha

Explain about disk scheduling with neat diagram, Explain about disk schedul...

Explain about disk scheduling with neat diagram? FCFS Scheduling SCAN scheduling C-SCAN scheduling SSTF scheduling LOOK Scheduling

Cpu, Some CPUs provide for more than two modes of operation. What are two p...

Some CPUs provide for more than two modes of operation. What are two possible uses of these multiple modes?

What are privileged instructions, What are privileged instructions? Som...

What are privileged instructions? Some of the machine instructions that may cause harm to a system are designated as privileged instructions. The hardware permits the privilege

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd