LinuxQuestions.org
Support LQ: Use code LQ3 and save $3 on Domain Registration
Go Back   LinuxQuestions.org > Forums > Linux Forums > Linux - Newbie
User Name
Password
Linux - Newbie This Linux forum is for members that are new to Linux.
Just starting out and have a question? If it is not in the man pages or the how-to's this is the place!

Notices

Reply
 
Search this Thread
Old 08-05-2009, 11:25 AM   #1
blittrell
LQ Newbie
 
Registered: Feb 2009
Location: Silicon Valley
Posts: 19

Rep: Reputation: 0
What does free memory mean in top?


Hi All,

I would not exactly consider myself a newbie but this is a bit of a newbie question so here it goes.

When I run top I see used memory and free memory. When I first boot the system there is lots of free memory in about a day or two that memory whittles down from 2GB of Free mem(of 4GB) to 20MB and then maintains 20-50MB of free memory. This seems to be consistent across different servers. At first I thought there had to be some major memory leaks but it just seemed to prevalent to not have been noticed before.

So reading these forums I found a better way to gauge memory usage is the use of the free command. Now I am confused though, what is Free memory as it is defined and monitored in top?

Thanks
 
Old 08-05-2009, 11:35 AM   #2
blittrell
LQ Newbie
 
Registered: Feb 2009
Location: Silicon Valley
Posts: 19

Original Poster
Rep: Reputation: 0
Hi All,

Guess it just takes a few minutes to search the Internet and I found the answer, Disk cache uses up the memory and so the memory is not free, it is used for Disk cache, I assume that means that other programs that need the memory can pull from that disk cache memory and use it but top is still going to show it as used.

Thanks and sorry for spamming the forum
 
Old 08-05-2009, 11:42 AM   #3
tredegar
Guru
 
Registered: May 2003
Location: London, UK
Distribution: Ubuntu 10.04, mostly
Posts: 6,007

Rep: Reputation: 367Reputation: 367Reputation: 367Reputation: 367
Quote:
Guess it just takes a few minutes to search the Internet and I found the answer ....[SNIP] I assume that means that other programs that need the memory can pull from that disk cache memory and use it but top is still going to show it as used.
Correct.
Quote:
Thanks and sorry for spamming the forum
I expect you will eventually be forgiven.

Searching for answers before you post to LQ is always a good idea
 
Old 08-05-2009, 12:10 PM   #4
i92guboj
Gentoo support team
 
Registered: May 2008
Location: Lucena, Córdoba (Spain)
Distribution: Gentoo
Posts: 4,036

Rep: Reputation: 373Reputation: 373Reputation: 373Reputation: 373
Memory classified as "buffers" or "cached" is essentially free memory as well, as you already found. Having the memory empty when it can be used to improve the performance would be a pitiful waste.
 
  


Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Why doesnt top or free show swap memory usage ? exceed1 Linux - General 15 08-03-2009 08:38 PM
[SOLVED] Memory leak: How risky not to free allocated memory. kaz2100 Linux - General 1 12-24-2008 12:00 AM
To find the process that uses the most memory using top nano2 Linux - Server 2 06-12-2008 10:02 AM
Memory usage using TOP FantaJ Linux - Newbie 2 03-05-2008 12:35 PM
web browsers slow, little memory free, pleae review output from top jeffreybluml Linux - Newbie 31 07-03-2004 08:15 PM


All times are GMT -5. The time now is 03:18 PM.

Main Menu
My LQ
Write for LQ
LinuxQuestions.org is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
Syndicate
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
identi.ca: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration