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

Three conditions that solution for critical section problem, What are three...

What are three conditions that a solution for the critical section problem must satisfy? The three conditions are as following:- a)      Mutual exclusion :- if a process is

Digital circuits and design , 1. Draw a schematic diagram of a CMOS inverte...

1. Draw a schematic diagram of a CMOS inverter and explain its operation. 2. Draw schematic diagrams of CMOS NAND and NOR gates, and explain their operation. 3. Explain what

Drawbacks of least-recently used algorithm, The question of fairness, regar...

The question of fairness, regarding page eviction, is a hard one. How do we decide what is fair? Many operating systems use global LRU, where pages from all processes are managed t

Explain acyclic-graph directories, Acyclic-graph directories An acyclic...

Acyclic-graph directories An acyclic graph permits directories to have shared subdirectories and files. The similar file or subdirectory may be in two dissimilar directories. A

Define a public key encryption system, Define a public key encryption syste...

Define a public key encryption system Allows just the correct receiver to decode the data

Define paging , Paging: Only the needed memory pages are moved to main me...

Paging: Only the needed memory pages are moved to main memory from the swap machine for execution. Process size does not matter. Produce the concept of the virtual memory. It

VB. Net & XML, Write a XML with database with book details (BOOK ID, Title,...

Write a XML with database with book details (BOOK ID, Title, Author, subject, publisher year, language, vendor, and price)

Life of a page, Suppose your process starts up, and allocates some memory w...

Suppose your process starts up, and allocates some memory with malloc(). The allocator will then give part of a memory page to your process. The OS then updates the corresponding p

Bounded and unbounded buffer, Ask question #Minimum 100 difference between ...

Ask question #Minimum 100 difference between bounded and unbounded buffer words accepted#

Management, what is secondary storage management

what is secondary storage management

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