Docker using huge amount of swap memory on Ubuntu 15.04, why?

Question

I am suffering from excessive memory usage, currently amounting to ~940 MB physical and ~1 GB swap memory, on my Ubuntu 15.04 x64 Docker (1.9.1-cs2, build 4ade326) host. According to top, Docker is responsible for the consumption of about 780 MB of swap memory. How can I figure out why Docker is using so much swap?

I am mainly running a Node.js Docker container, which doesn't seem to consume that much memory. The memory usage is also rising over a few hours, as it's quite modest after booting up.

I've enabled memory/swap accounting on the node now, hoping this will reign the swap usage in. — aknuds1, Jan 13 '16 at 11:01
What do you mean by "According to `top`, Docker is responsible for the consumption of about 780 MB of swap memory"? I suspect you have misread the output. — Michael Hampton, Jan 13 '16 at 13:05
@MichaelHampton I was reading top's `swap` column for the docker process, quite simply. — aknuds1, Jan 13 '16 at 13:10

score 1 · Accepted Answer · answered Jan 16 '16 at 16:55

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It's not a super satisfying answer, but enabling memory and swap accounting in the kernel seems to have reined in the excessive memory usage.

answered Jan 16 '16 at 16:55

aknuds1

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Unfortunately, I see Docker is back to using ~780 MB of swap :( It is the `docker` process itself (according to /proc//status) that is responsible for this. – aknuds1 Jan 27 '16 at 12:21

Docker using huge amount of swap memory on Ubuntu 15.04, why?

1 Answers1