[Metricbeat] Add new metrics for swapin/out

[radoondas]

Describe the enhancement:
Hi, I would like to be able to collect metrics from swapin/out as showed below.

root@server42:/etc/systemd/system# cat /proc/vmstat|grep swp
pswpin 399224
pswpout 1291234

Thanks

[fearful-symmetry]

Looking into this. On linux, the current swap stat implementation used by elastic/gosigar uses /proc/meminfo and not /proc/vmstat. However, it shouldn't be hard to grab the vmstat metrics and add them to the (limited) swap data we're getting from meminfo.

[fearful-symmetry]

So, oddly enough, I don't see anything in gosigar that reads from the vmstat procfs file under linux. Gonna have to start there.

[fearful-symmetry]

Okay, finally starting work on this. It looks like we'll be using the elastic/go-sysinfo library.

[kkh-security-distractions]

Greta to hear, that this is underway There could be other useful stuff i /proc/vmstat , but swap info is key for us right now. Let us if you want some beta testers , happy to help out.

[fearful-symmetry]

This is merged, and should be in 7.5

[kkh-security-distractions]

awesome ,thnx