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

Batch system, what is a batch system give me answer in simple words so that...

what is a batch system give me answer in simple words so that i can understand

Ipc, explain in detail about ipc in linux

explain in detail about ipc in linux

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 a brief note on demand paging, Write a brief note on demand paging. ...

Write a brief note on demand paging. A demand paging is alike to a paging system with swapping. The Processes reside on the secondary memory while we want to implement a proces

Define the sleep (sec) function, Define the Sleep (sec) Function Sleep ...

Define the Sleep (sec) Function Sleep function suspends execution of this process for sec number of seconds. While this function is used in our example for consistency, other f

Explain single partition allocation., Operating Systems 1. Explain sing...

Operating Systems 1. Explain single Partition Allocation and Multiple Partition Allocation. 2. What do you mean by PCB? What useful information is available in PCB? 3. De

BARBER SHOP PROBLEM, a) The barber shop has one barber, one barber chair, a...

a) The barber shop has one barber, one barber chair, and n chairs for waiting customers, to sit on. If there are no customers present, the barber sits down in the barber chair and

Estimate the continued transfer rate of drive, Q. The term "fast wide SCSI...

Q. The term "fast wide SCSI-II" signifies a SCSI bus that operates at a data rate of 20 megabytes per second when it moves a packet of bytes among the host and a device. Presume t

Write a short note on memory management, Write a short note on Memory manag...

Write a short note on Memory management. Memory management includes reallocating and allocating the memory space. The kinds of allocation of memory FIXED PARTITIONING

What effect would updating a few byte on the one page, Q. What is the effe...

Q. What is the effect of permitting two entries in a page table to point to the same page frame in memory? Describe how this effect could be used to decrease the amount of time ne

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