Swap, Swapiness and Standby: swapping starts when waking up
- by mdo
I'm running running Ubuntu 12.04 on a Lenovo W500 (Core2Duo T9400, 4GB Ram)
Current kernel: 3.2.0-32-generic #51-Ubuntu SMP Wed Sep 26 21:33:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux -- but the problems exists since a couple of months, surviving quite a few software (includig kernel) updates
I regularly put my machine into suspend-to-ram (S3) and when the machine comes back up Ubuntu starts to swap out processes. I was able to observe that the used swap-space starts to grow right after the box returns. See munin graphs below, the gap (obviously) shows the timeframe in STR.
Needless to say that the box becomes unusable while swapping, load goes up beyond 10.
What I've done so far:
lowered swappiness from default (60) to 10 (via /etc/sysctl.conf: vm.swappiness=10) -- this has improved the situation much, but sometimes the problem comes back, I have not found a trigger (like memory usage) for this for now
lowered swappiness to 5 -- perhaps this has brought an improvement again
Before going to STR the box ran stable without (swapping) problems for hours. Today when the issue showed up again I used this script (- http://stackoverflow.com/questions/479953/how-to-find-out-which-processes-are-swapping-in-linux) to find what processes have the most used swap space. The result after the swap orgy is like that (all PIDs with more than 10M usage):
Overall swap used: 2121344 kB
========================================
kB pid name
========================================
439520 17491 java
208148 22719 firefox
136640 4337 /usr/bin/quodli
120852 5271 chrome
81832 5264 chrome
74284 17003 chrome
65368 16960 chrome
57088 3675 chrome
56184 30923 chrome
54412 11331 chrome
54264 3878 chrome
51508 18382 chrome
50088 3163 zeitgeist-fts
49772 15543 chrome
41344 15355 compiz
35040 1161 mysqld
32124 18374 chrome
30940 11339 chrome
30044 5752 chrome
28780 4235 plugin-containe
24576 31246 empathy-chat
23840 17703 chrome
22512 3207 ubuntuone-syncd
21588 1937 ntop
18336 2021 asterisk
17200 3915 chrome
13964 1935 Xorg
12036 10679 chrome
11104 30782 empathy
11056 2889 python
10932 16565 knotify4
The java instance at the top is IntelliJ. IntelliJ, Firefox and Chrome also were all used right before the box was put to STR.
So my question is: can I somehow prevent these swapouts AND why do they happen? Is it perhaps related to some misidentification of idle processes?
I'm not looking for resolutions like:
turn off swap
buy more RAM
Thanks in advance!
