Swap is not copied back into physical memory

Posted by GradGuy on Ask Ubuntu See other posts from Ask Ubuntu or by GradGuy
Published on 2012-03-26T22:45:35Z Indexed on 2012/03/26 23:39 UTC
Read the original article Hit count: 253

Filed under:

10.10

|

swap

|

memory

I have a question regarding swap and physical memory. Often times I run a program that requires a lot of memory and as a result I can see some of the data is copied from the physical memory into swap. However, once the program is terminated, and the physical memory is freed I can still see a considerable amount of data on swap which significantly slows down the system and is annoying!

What is the reason behind this and how does the OS decide which part of data should go to swap? How long is this data supposed to be there and how is it "freed"?

© Ask Ubuntu or respective owner

Related posts about 10.10

How can I upgrade to 10.10 from 10.10 beta

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
Can you please tell me how can I upgrade to ubuntu 10.10 release from ubuntu 10.10 beta? I have go to update manager, it keeps saying there is no update. And what I go to synaptic package manager, I see this error: W: A error occurred during the signature verification. The repository is not updated… >>> More
Bridged network between Ubuntu Desktop 10.10 host and Ubuntu Server 10.10 Guest

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I run Ubuntu 10.10 Desktop on my machine and have installed Ubuntu Server 10.10 in a Virtualbox VM. I'm running Virtualbox 4.0.2. It is not virtualbox-ose. I'd like the guest OS to have an IP address on my local network so that I can run server software and access this from the host OS. My intention… >>> More
Merging /boot and rearranging grub2 entries

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have used 10.10 and now for testing purposes installed 10.04 to a separate partition. 10.10 is currently on a single partition, while for 10.04 I decided to separate /boot to a third partition. Now my questions: How can I move and merge 10.10's /boot on the new /boot partition What do I have to… >>> More
Merging /boot and rearring grub2 entries

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have used 10.10 and now for testing purposes installed 10.04 to a separate partition. 10.10 is currently on a single partition, while for 10.04 I decided to separate /boot to a third partition. Now my questions: How can I move and merge 10.10's /boot on the new /boot partition What do I have to… >>> More
Boot failure : No DEFAULT or UI configuration directive found!

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I've tried to install Ubuntu on a VMWare Virtual Machine, but it never get's past the bootloader : ISOLINUX 4.01 debian-20100714 ETCD Copyright (C) 1994-2010 H. Peter Anvin et al No DEFAULT or UI configuration directive found! boot: _ I've also tried to burn this .iso image to a CD and go from… >>> More

Related posts about swap

Write-error on swap-device, Result: hostbyte=DID_BAD_TARGET driverbyte=DRIVER_OK

as seen on Server Fault - Search for 'Server Fault'
My root server at 1&1 was unresponsive on HTTP and SSH, so I logged into the serial console . It flooded my connection with endless error messages like quoted below. I initiated a reboot and now everything seems to work properly. After googling, I installed smartctl and ran a short self test… >>> More
GNU/Linux swapping blocks system

as seen on Server Fault - Search for 'Server Fault'
I have used GNU/Linux on systems from 4 MB RAM to 512 GB RAM. When they start swapping, most of the time you can still log in and kill off the offending process - you just have to be 100-1000 times more patient. On my new 32 GB system that has changed: It blocks when it starts swapping. Sometimes… >>> More
Swap partition not recognized (The disk drive with UUID=... is not ready yet or not present)

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I think I had an encrypted swap partition, because I chose to encrypt my home directory during the installation. I believe that's what the line with /dev/mapper/cryptswap1 ... in my /etc/fstab is all about. I did something to bork my swap because on the next boot, I got a message (paraphrased): … >>> More
Newbie ask Swap Value: How much Swap do I have?

as seen on Server Fault - Search for 'Server Fault'
When looking vmstat, this is what I got: procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ r b swpd free buff cache si so bi bo in cs us sy id wa st 1 0 0 2872 0 0 0 0 8 17 0 14 3 1 94 2 0 the cache… >>> More
Crash and Centos

as seen on Server Fault - Search for 'Server Fault'
Hello guys and girls, I've a big problem it's the second time that my server crashed. I tried to check every thing and seems correct except this /var/log/messages: May 25 20:16:11 srv1 kernel: swap_free: Bad swap offset entry 00300000 May 25 20:16:33 srv1 kernel: swap_free: Unused swap offset… >>> More