[2.3, HWTv2] Memtester test is not robust

[Andres Rodriguez]

In machines with 32gb of ram, I noticed that memtester would always fail when running hardware testing. The errors I saw showed that MAAS could timeout at about 11 minutes, and the event log showed that the machines missed the past 5 heartbeats.

What I did is to try to run the tests manually on the same, and came across a couple of interesting things:

### This is the test that MAAS runs:

root@node04:/home/ubuntu# memtester $(awk '/MemFree/ { print ($2 - 32768) "K"}' /proc/meminfo) 1
memtester version 4.3.0 (64-bit)
Copyright (C) 2001-2012 Charles Cazabon.
Licensed under the GNU General Public License version 2 (only).

pagesize is 4096
pagesizemask is 0xfffffffffffff000
want 31289MB (32809152512 bytes)
got 31284MB (32803975168 bytes), trying mlock ...Killed

### I changed this to use MemAvailable instead, and the machine locked up.

root@node04:/home/ubuntu# memtester $(awk '/MemAvailable/ { print ($2 - 32768) "K"}' /proc/meminfo) 1
memtester version 4.3.0 (64-bit)
Copyright (C) 2001-2012 Charles Cazabon.
Licensed under the GNU General Public License version 2 (only).

pagesize is 4096
pagesizemask is 0xfffffffffffff000
want 31081MB (32591736832 bytes)
got 31081MB (32591736832 bytes), trying mlock ...locked.
Loop 1/1:
  Stuck Address : setting 0

[Andres Rodriguez (andreserl)]

$(awk '/MemFree/ { print ($2 - 32768) "K"}' gave me: 31787072K

I re-run the test manually with : sudo -n memtester 29000000K 1

And this time it didn't lock up