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

Ipc, Explain in detail about ipc in linux

Explain in detail about ipc in linux

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

What is external fragmentation?, What is external fragmentation? As pro...

What is external fragmentation? As process are removed from and loaded to the memory free memory space is bracken into pieces .external fragmentation take place when enough mem

What are the various disk-scheduling algorithms, What are the various disk-...

What are the various disk-scheduling algorithms? The several disk-scheduling algorithms are a. First Come First Served Scheduling b. Shortest Seek Time First Scheduling

Multilevel page table, what is multilevel page table and its applications?

what is multilevel page table and its applications?

Microsoft, Discuss the high barriers to entry in the market for PL operatin...

Discuss the high barriers to entry in the market for PL operating systems

Define fifo page replacement algorithm, Define FIFO Page Replacement Algori...

Define FIFO Page Replacement Algorithm This policy simply eliminates pages in the order they arrived in the main memory. By using this policy we simply remove a page based upo

What is page fault and how to remove page fault?, What is page fault and wh...

What is page fault and what are the steps taken by the OS to remove page fault? A page fault is caused while a page that hasn't been brought into memory is being addressed. The

Multiprogramming, how response times are reduced by allowing time sharing o...

how response times are reduced by allowing time sharing on top of multiprogramming

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