Description of problem:

When you run OST's basic suite you can see in the 'vdsm.log':

2019-07-25 10:26:50,567-0400 DEBUG (jsonrpc/4) [jsonrpc.JsonRpcServer] Calling 'Host.setKsmTune' in bridge with {u'tuningParams': {u'pages_to_scan': 64, u'run': 1, u'sleep_millisecs': 89.25152465623417}} (__init__:329)
2019-07-25 10:26:50,583-0400 ERROR (jsonrpc/4) [vds] setKsmTune API call failed. (API:1660)
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/vdsm/API.py", line 1657, in setKsmTune
    supervdsm.getProxy().ksmTune(tuningParams)
  File "/usr/lib/python2.7/site-packages/vdsm/common/supervdsm.py", line 56, in __call__
    return callMethod()
  File "/usr/lib/python2.7/site-packages/vdsm/common/supervdsm.py", line 54, in <lambda>
    **kwargs)
  File "<string>", line 2, in ksmTune
  File "/usr/lib64/python2.7/multiprocessing/managers.py", line 773, in _callmethod
    raise convert_to_error(kind, result)
IOError: [Errno 22] Invalid argument

This error is caused by trying to write a floating point value to '/sys/kernel/mm/ksm/sleep_millisecs' and can be reproduced manually with i.e.:

echo 5.4 > /sys/kernel/mm/ksm/sleep_millisecs

'ksm' interfaces accept ints only and VDSM's verb schema follows these rules:

https://github.com/oVirt/vdsm/blob/master/lib/vdsm/api/vdsm-api.yml#L3258

The default policy shipped with VDSM uses some math to obtain the 'sleep_millisecs' value:

https://github.com/oVirt/vdsm/blob/e5c4450f58e119aed34cf23fcca39ecbd345fab4/static/etc/vdsm/mom.d/03-ksm.policy#L108

But the result of that calculation is a floating point number - it should be trimmed/rounded to an int.


How reproducible:

Always.

Steps to Reproduce:
1. Run OST's basic suite
2. Look for 'setKsmTune'-related errors in 'vdsm.log', 'supervdsm.log' and 'mom.log'

Actual results:

MOM passes a floating point value for 'sleep_millisecs' field when calling 'Host.setKsmTune' VDSM's verb.

Expected results:

MOM passes a trimmed/rounded integer value for 'sleep_millisecs' field when calling 'Host.setKsmTune' VDSM's verb.