Zswap: Compressed Swap Caching For Linux

What is the advantage of zswap over using zram for swap? They sound very similar.

marco, FourDMusic thanks for the info.

So is there some module that should deprecate others? I suppose at least zcache2 vs. zcache? What about others, zram should just be moved out of staging in 3.8. Or every one has its purpose?

Yes thanks for the rundown on these different schemes guys. So, as someone who hasn't used swap at all since all my machines had atleast 4gb ram I'm mostly interested zcache from what I'm reading here. Is it anywhere near getting into mainline?

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Originally Posted by XorEaxEax

Yes thanks for the rundown on these different schemes guys. So, as someone who hasn't used swap at all since all my machines had atleast 4gb ram I'm mostly interested zcache from what I'm reading here. Is it anywhere near getting into mainline?

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zcache has been in mainline for ages.

zram vs. zwasp, see also this: https://www.ibm.com/developerworks/m...-1355393967955

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Originally Posted by YAFU

Oh! I hope Zswap will improve swap and system performance.
Everyone knows that especially in Linux, when the swap is used the system performance is disastrous. I know this should be normal because the speed of the hard disk, but Linux swap have worse performance compared to other systems who do heavy usage of the paging file. I think this problem is well known in Linux because there is much written on the internet to avoid the swap usage changing the swappiness.

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In my experience Linux is much better with harddisk access than Windows. Windows constantly wants to access your harddisk. Linux tries to avoid swap as much as possible.

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Originally Posted by Ferdinand

In my experience Linux is much better with harddisk access than Windows. Windows constantly wants to access your harddisk. Linux tries to avoid swap as much as possible.

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Yes, you are right. You search about the "swappiness" that I had mentioned before and you will understand it better. Windows uses virtual memory from the start. But when Linux uses the swap it has a very poor performance in comparison. Mainly when data are moving. Can be created bottlenecks and the system can even hung completely. It's something in my approx 12 years as a Linux user I have not seen great improvements.