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

Explain the concept of reentrancy, Concept of Reentrancy   It is a ...

Concept of Reentrancy   It is a useful, memory-saving method for multiprogrammed timesharing machines. A Reentrant method is one in which multiple clients can share a singl

What are the deadlock prevention methodologies?, What are the deadlock p r...

What are the deadlock p revention methodologies? a.       Necessitate that processes request all resources before starting - if cannot be granted don't run. b.      Process

What is preallocation, What is preallocation? Why do it? Allocating spa...

What is preallocation? Why do it? Allocating space for a file before making the file to allow for expansion. This reserves space for a certain file so that other files can't gr

Operational management, explain the link between operations management and ...

explain the link between operations management and strategic planning of daily goods shop

Explain the performance of demand paging, Performance of demand paging ...

Performance of demand paging Demand paging can have an important effect on the performance of a computer system. As long as there are no page faults, the effective access time

Changing the runlevel of system from 5 to 3 on startup, Front page We n...

Front page We need to continue or customization and documentation of our system. Currently our system boots into runlevel 5 and we need it to boot into runlevel 3. For future r

Explain deadlock detection and recovery, Deadlock Detection and Recovery ...

Deadlock Detection and Recovery It's a method of permitting the system to enter a deadlock state, detect it and then recover. Deadlock detection : Is the process of

Conservative garbage collection, Conservative GC can be used for languages ...

Conservative GC can be used for languages such as C and C++, which were not explicitly designed for garbage collection. This is a non-copying technique. A conservative garbage coll

Why do organisations need a structure, Problem 1: (a) The grouping of o...

Problem 1: (a) The grouping of organisational activities (usually into ‘departments' or larger ‘divisions') can be done in different ways. Outline 7 criteria which can be used

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