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 basic method of paging method, Explain the basic method of pagi...

Explain the basic method of paging method. Physical memory is divided into the fixed-sized blocks called frames. Logical memory is as well divided into blocks of the same size

Explain benefits of time-sharing system, Under what circumstances would a ...

Under what circumstances would a user be better off using a time-sharing system, rather than a personal computer or single-user workstation? When there are some other users, th

What are the drawbacks of spiral model, What are the drawbacks of spiral mo...

What are the drawbacks of spiral model? I. It is based on customer communication. If the communication is not proper then the software product that gets developed will not be t

Explain the various page replacement strategies, Explain the various page r...

Explain the various page replacement strategies. Page replacement-basic scheme with diagram Optimal page replacement LRU page replacement FIFO page replacement LRU

Explain inverted page table, Inverted page table In page table the page...

Inverted page table In page table the page table has one entry for every page that the process is using. The operating system must translate this reference into a physical memo

Explain first fit algorithm, FIRST FIT ALGORITHM Scanning a list along...

FIRST FIT ALGORITHM Scanning a list along with if a free hole is available with necessary space for the process to allocate it allocates the process in that space. The first s

Define maintaining data on a per client basis, Define Maintaining Data on a...

Define Maintaining Data on a Per Client Basis Perhaps the most dramatic syntactical programming change for the application developer of client – server applications is maintain

What is spooling, What is spooling? Spooling overlaps the I/O of single...

What is spooling? Spooling overlaps the I/O of single job with the computation of other jobs.

Deadlock, Suppose we have 3 processes running at the same time as shown in ...

Suppose we have 3 processes running at the same time as shown in the following table. Each resource only has one instance. Show a possible scenario of resource allocation that r

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