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
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10.10

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swap

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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"?

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