Bug 4.9 and memorymanagement

From: Klaus Ethgen
Date: Sun Dec 25 2016 - 16:37:02 EST


The last days I compiled version 4.9 for my i386 laptop. (Lenovo x61s)

First, everything seems to be sane but after some sleep and awake
(suspend to ram) cycles I seen some really weird behaviour ending in OOM
or even complete freeze of the laptop.

What I was able to see is that it went to swap even if there is plenty
of memory left. The OOMs was also with many memory left.

Once I also catched kswapd0 with running insane with 100% CPU

I first had in mind the CONFIG_SLAB_FREELIST_RANDOM setting and disabled
it. This didn't made the problem to go away but it helped a little.
Nevertheless, further OOM or other strange behaviour happened.

I went back to 4.8.15 now with the same config from 4.9 and everything
gets back to normal.

So it seems for me that there are some really strange memory leaks in
4.9. The biggest problem is, that I do not know how to reproduce it
reliable. The only what I know is that it happened after several
suspends. (Not necessarily the first.)

Am I the only one seeing that behavior or do anybody have an idea what
could went wrong?

For the reference I put the .configs of the two compilings as attachment
to this mail.

Please keep me in CC as I am not subscribed to LKML.

Klaus Ethgen http://www.ethgen.ch/
pub 4096R/4E20AF1C 2011-05-16 Klaus Ethgen <Klaus@xxxxxxxxx>
Fingerprint: 85D4 CA42 952C 949B 1753 62B3 79D0 B06F 4E20 AF1C

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