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

Illustrate example for segmentation, EXAMPLE FOR SEGMENTATION Consider ...

EXAMPLE FOR SEGMENTATION Consider an instance as given in the table and we have five segments numbered from 0 through 4 the segment is stock in the physical memory as shown. Th

What are the necessary conditions for deadlocks?, What are the necessary co...

What are the necessary conditions for deadlocks? 1. Mutual exclusion :  Only one process at a time is able to use the resource. 2. Hold and wait :  A process should be holdi

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

Components of the r/e system, What components of the R/e system initiate th...

What components of the R/e system initiate the start of background jobs at the specified time? The batch scheduler initiates the begin of background job.  The dispatcher then s

Why we need to use a while statement when using wait method, Q. The wait()...

Q. The wait() statement in every Java program examples was part of a while loop. Describe why you would always need to use a while statement when using wait() and why you would ne

Unix, difference between soft link and hard links

difference between soft link and hard links

Optimal replacement policy, The optimal replacement policy, called OPT, is ...

The optimal replacement policy, called OPT, is to evict the page which will be accessed farthest into the future. Since we can't predict the future precisely, we can't implement OP

Explain threads for executing concurrent application code, Explain Threads ...

Explain Threads for Executing Concurrent Application Code The thread has been introduced in many operating systems as an efficient mechanism for executing concurrent applicatio

Request or response interface - interaction using message, Explain the Requ...

Explain the Request or Response interface The Request/Response interface is ideal for a message based client-server interaction. By modeling components to interact via a reque

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