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

Algorithm for reconstructing a logical ring, Q. Present an algorithm for re...

Q. Present an algorithm for reconstructing a logical ring after a process in the ring fails? Answer: Typically distributed systems utilize a coordinator process that performs

What is the translation look aside buffer (tlb), Translation Look aside Buf...

Translation Look aside Buffer In a cached system, the base addresses of the last few indexed pages is maintained in registers named the TLB that adds in faster lookup. TLB has

Explain threads in details?, What are threads? A thread - sometimes c...

What are threads? A thread - sometimes called as an implementation context or a lightweight process - is a single sequential flow of control within a program. We use threads

Homework, Write an application that does the following:(1) fill an array wi...

Write an application that does the following:(1) fill an array with 50 random integers; (2) loop through the array, displaying each value, and count the number of negative values;

Multilevel queue scheduling, Explain multilevel queue scheduling and multil...

Explain multilevel queue scheduling and multilevel feedback queue scheduling #Minimum 100 words accepted#

Why is it complicated to protect a system, Q. Why is it complicated to prot...

Q. Why is it complicated to protect a system in which users are allowed to do their own I/O? Answer: In earlier chapters we identified a distinction among kernel and user mod

Determine scheduling policy for time-shared operating system, Determine a s...

Determine a scheduling policy that is most suitable for a time-shared operating system   Round-Robin is a scheduling policy that is most suitable for a time-shared operating s

Multilevel page table, what is multilevel page table and its applications?

what is multilevel page table and its applications?

Control the access of the three global variables, Give a brief introduction...

Give a brief introduction about the operation of your program and show that you understand the idea behind threads and mutual exclusion variable. Why do we need to use mutual exclu

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