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

Define rotational latency and disk bandwidth, Define rotational latency and...

Define rotational latency and disk bandwidth. Rotational latency is the additional time waiting for the disk to rotate the wanted sector to the disk head. The disk bandwidth is

What is a client server system, What is a client server system? Central...

What is a client server system? Centralized systems proceed as server systems to satisfy request generated by client systems Server system is able to be broadly div

Define abbreviation of sstf, SSTF stands for Abbreviation of SSTF is S...

SSTF stands for Abbreviation of SSTF is Shortest-Seek-time-first scheduling

Single-level page tables, As mentioned above, page tables, are lookup table...

As mentioned above, page tables, are lookup tables mapping a process' virtual pages to physical pages in RAM. How would one implement these page tables? The most straightforward

Cpu, Some CPUs provide for more than two modes of operation. What are two p...

Some CPUs provide for more than two modes of operation. What are two possible uses of these multiple modes?

What are tree-structured directories, What are Tree-structured directories ...

What are Tree-structured directories We can generalize the directory structure to a tree of arbitrary height. This permits the user to create their own sub directories and to c

Which algorithm makes the most efficient use of memory, Question : (a) ...

Question : (a) The dynamic allocation problem is how to satisfy a request of size n from a list of free holes into memory. The best-fit, first-fit and worst-fit strategies are

Linux, how to find ncr value in shell script

how to find ncr value in shell script

Explain the entry-sequenced file organization, Entry-sequenced file organiz...

Entry-sequenced file organization The records in an entry-sequenced file are store up in the order they are written into the file. New records are for all time appended to

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