100% CPU load by kswapd0 since upgrade to 15.10

[mtl-0]

Hi,


since upgrading my homeserver (Xbubuntu 15.04 x64) to Xubuntu 15.10 kswapd0 produces 100% cpu load. I helped that I set vm.swappiness = 0, but since yesterday I also get 100% cpu load when vm.swappiness set to 0. Using a higher value doesn't help either.
The server has 3GB of RAM and a 5GB swap file.


This didn't happen ever on Xubuntu 14.04., Xubuntu 14.10. or Xubuntu 15.04.

Anyone got a clue?


265294

[vuo]

I second this.

Same scenario except for using `zram-config` for swap: As soon as swap is used `kswapd0` uses up one CPU core's performance. Sometimes it's disappearing when closing a program like Firefox that caused swapping.

Configuration changes haven't resulted in any improvements. Large games are almost unplayable. Changing niceness of `kswapd0` is just slightly soothing to not have the system choking.

[vuo]

This solved it for me now:

There’s also quite a common problem with kswapd0 hogging CPU on the C720. I was able to get rid of this problem by setting transparent_hugepage to madvise. To do so, add this to /etc/rc.local:

echo madvise > /sys/kernel/mm/transparent_hugepage/enabled
from https://www.reddit.com/r/chrubuntu/comments/3ru04q/help_kernel_process_kswapd0_randomly_consuming/cwshnf2 respectively https://blogs.fsfe.org/the_unconventional/2014/04/20/c720-ubuntu/

I also had to disable all custom vm.* settings in /etc/sysctl.conf. With this the system works well again now.


I believe this issue has been introduced through the 4.2 kernel included in the Xubuntu upgrade. (This didn't occur with Ubuntu's 3.x and mainline kernels 4.0-4.1 before.)

I also noticed Xfce4's Power Manager Plugin at times consumed up to 300 MiB resident memory and switched to using the Indicator Plugin equivalent feature for this.

[mtl-0]

This solved it for me now:

from https://www.reddit.com/r/chrubuntu/comments/3ru04q/help_kernel_process_kswapd0_randomly_consuming/cwshnf2 respectively https://blogs.fsfe.org/the_unconventional/2014/04/20/c720-ubuntu/

I also had to disable all custom vm.* settings in /etc/sysctl.conf. With this the system works well again now.


I believe this issue has been introduced through the 4.2 kernel included in the Xubuntu upgrade. (This didn't occur with Ubuntu's 3.x and mainline kernels 4.0-4.1 before.)

I also noticed Xfce4's Power Manager Plugin at times consumed up to 300 MiB resident memory and switched to using the Indicator Plugin equivalent feature for this.

Thanks for the answer. Sadly this didnt fix it for me. Still 100% cpu load, even with no SWAP attached.

[zeroepoch]

Thank you so much!!! I tried commenting out my one option "vm.swapiness" in /etc/sysctl.conf but that made no difference. Running that command during normal operation didn't help. Although adding the command you mentioned to /etc/rc.d/rc.local (on Fedora 22) and rebooting did solve the problem. Now kswapd0 uses almost 0% CPU. I also had to disable tracker to get the rest of my idle CPU back but that's a GNOME 3 specific issue. Now my c720 launches firefox much faster.

[sistoviejo]

Is this the same as this other thread? https://ubuntuforums.org/showthread.php?t=2338503&highlight=kswapd0

[oldos2er]

Not exactly, this thread was about 15.10, not 16.04. 15.10 is EOL, so putting this one to bed.