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kswapd0 strikes again!


deltasig68

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About a year ago I reported the kswapd0 running out of control on OPi PC and Igor, after couple of tries made it behave.  Today, I got OPi One loaded with the latest 5.26 Ubuntu D/T and the OPi PC2 with today's daily Ubuntu D/T and both demonstrated the following behaviour when pressed for memory:

Specifically, running a "make -j2", when the available RAM got below 38000, the kswapd0 started getting more cpu time and eventually everything stopped waiting for disk I/O (80% wa displayed in "top").  Interestingly, not a single byte of swap storage was used.

I tried different combinations of programs and everything worked fine until the demands on RAM got the available RAM below 38000.  The sure fire combination were a long make (with just one thread) and FF displaying the finance page of yahoo!

This behaviour is, I dare say, identical to the one I encounter a year ago.   Any ideas?

Please, let me know if you need any more information.

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Thank you TK,

I did have a look at the link and followed through the write up. I got curious to see what the OPi PC had for these parameters since I run many times big projects on that on including the "make -j2" that crashed the H5 and the OPI One.

/proc/sys/vm/overcommit_memory=0, /proc/sys/vm/overcommit_ratio=50. The H5 that run the 4.10 had one more parameter /proc/sys/vm/overcommit_kbytes=0 (no idea what that does) and the swapiness for all is "0".

The system on the OPi PC is: 3.4.113-sun8i #10 SMP PREEMPT Thu Feb 23 19:55:00 CET 2017 armv7l armv7l armv7l GNU/Linux.

It run without any problem with memory usage getting as high as 80% and the swap (default swap of Armbian) got to 85%.

I'll play around with the parameters to see if something changes.

I have a question off this topic but I think you are the right person to ask: are the voltage/frequency parameters adjusted for the specific board before hand or do I have to go and fine tune? the H5 runs a bit on the "hot" side without much to do!  Thank you.

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are the voltage/frequency parameters adjusted for the specific board before hand or do I have to go and fine tune? the H5 runs a bit on the "hot" side without much to do!  Thank you.

 

I've sent 'my' OPi PC2 to another dev months ago so I'm a bit cut off from actual H5 topics (also NanoPi NEO2 dev sample -- based on H5 too -- never arrived here). Please look for some information (and ask questions) in this thread: https://forum.armbian.com/index.php/topic/2869-armbian-for-orangepi-pc2-allwinner-h5/page-1 (@ErwinH developed dvfs/cpufreq settings that should be tested by many users and we have also reports that default cpufreq governor 'schedutil' doesn't work as expected -- feedback welcome).

 

Also looking forward to your 'overcommitment' results here :)

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