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

Write a linux script to add name in class list, For this exercise I wanted ...

For this exercise I wanted to give you some real-world examples of useful bash scripts. Therefore, you will write a couple of scripts that I actually use in my teaching to automate

Explain best fit algorithm, BEST FIT ALGORITHM Here scanning is for th...

BEST FIT ALGORITHM Here scanning is for the finest fit one. Signifies it searches the entire list for the best fit position. For the process therefore in that the process will

What is long-term, What is long-term, medium-term, short-term? In a bat...

What is long-term, medium-term, short-term? In a batch system many processes are submitted than are able to be executed immediately. These processes are reel to a mass storage

Explain process description in the unix system, Process Description A pr...

Process Description A process in UNIX is a somewhat complex set of data structures that provides the operating system with all of the information necessary to dispatch and manag

Define pure and impure interpreters, Pure and impure interpreters      ...

Pure and impure interpreters      In a pure interpreter, the source program is maintained in the source form throughout its interpretation. This arrangement acquires substantia

Explain the tlssetvalue (tlsindex, Explain the TlsSetValue (TLSindex, dataP...

Explain the TlsSetValue (TLSindex, dataPtr)Function The TlsSetValue function  associates the  dataPtr passed as a parameter as local storage for the requesting thread. The asso

What kind of protection structure do we have, Q. Consider a calculating en...

Q. Consider a calculating environment where a unique number is associated with each process and each object in the system. Suppose that we permit a process with number n to acce

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