#!/usr/bin/python2
# -*- coding: utf-8 -*-
# pylint: skip-file
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
# Copyright (C) 2013 Marek Marczykowski <marmarek@invisiblethingslab.com>
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
#
import logging
import os
import string
import time
import xen.lowlevel.xc
import xen.lowlevel.xs
import qubes
import qubes.qmemman.algo
no_progress_msg="VM refused to give back requested memory"
slow_memset_react_msg="VM didn't give back all requested memory"
class DomainState:
def __init__(self, id):
self.meminfo = None #dictionary of memory info read from client
self.memory_current = 0 # the current memory size
self.memory_actual = None # the current memory allocation (what VM
# is using or can use at any time)
self.memory_maximum = None #the maximum memory size
self.mem_used = None #used memory, computed based on meminfo
self.id = id #domain id
self.last_target = 0 #the last memset target
self.no_progress = False #no react to memset
self.slow_memset_react = False #slow react to memset (after few tries still above target)
def __repr__(self):
return self.__dict__.__repr__()
class SystemState(object):
def __init__(self):
self.log = logging.getLogger('qmemman.systemstate')
self.log.debug('SystemState()')
self.domdict = {}
self.xc = xen.lowlevel.xc.xc()
self.xs = xen.lowlevel.xs.xs()
self.BALOON_DELAY = 0.1
self.XEN_FREE_MEM_LEFT = 50*1024*1024
self.XEN_FREE_MEM_MIN = 25*1024*1024
# Overhead of per-page Xen structures, taken from OpenStack nova/virt/xenapi/driver.py
# see https://wiki.openstack.org/wiki/XenServer/Overhead
# we divide total and free physical memory by this to get "assignable" memory
self.MEM_OVERHEAD_FACTOR = 1.0 / 1.00781
try:
self.ALL_PHYS_MEM = int(self.xc.physinfo()['total_memory']*1024 * self.MEM_OVERHEAD_FACTOR)
except xen.lowlevel.xc.Error:
self.ALL_PHYS_MEM = 0
def add_domain(self, id):
self.log.debug('add_domain(id={!r})'.format(id))
self.domdict[id] = DomainState(id)
# TODO: move to DomainState.__init__
target_str = self.xs.read('', '/local/domain/' + id + '/memory/target')
if target_str:
self.domdict[id].last_target = int(target_str) * 1024
def del_domain(self, id):
self.log.debug('del_domain(id={!r})'.format(id))
self.domdict.pop(id)
def get_free_xen_memory(self):
xen_free = int(self.xc.physinfo()['free_memory']*1024 *
self.MEM_OVERHEAD_FACTOR)
# now check for domains which have assigned more memory than really
# used - do not count it as "free", because domain is free to use it
# at any time
# assumption: self.refresh_memactual was called before
# (so domdict[id].memory_actual is up to date)
assigned_but_unused = reduce(
lambda acc, dom: acc + max(0, dom.last_target-dom.memory_current),
self.domdict.values(),
0
)
# If, at any time, Xen have less memory than XEN_FREE_MEM_MIN,
# it is a failure of qmemman. Collect as much data as possible to
# debug it
if xen_free < self.XEN_FREE_MEM_MIN:
self.log.error("Xen free = {!r} below acceptable value! "
"assigned_but_unused={!r}, domdict={!r}".format(
xen_free, assigned_but_unused, self.domdict))
elif xen_free < assigned_but_unused+self.XEN_FREE_MEM_MIN:
self.log.error("Xen free = {!r} too small for satisfy assignments! "
"assigned_but_unused={!r}, domdict={!r}".format(
xen_free, assigned_but_unused, self.domdict))
return xen_free - assigned_but_unused
#refresh information on memory assigned to all domains
def refresh_memactual(self):
for domain in self.xc.domain_getinfo():
id = str(domain['domid'])
if self.domdict.has_key(id):
# real memory usage
self.domdict[id].memory_current = domain['mem_kb']*1024
# what VM is using or can use
self.domdict[id].memory_actual = max(
self.domdict[id].memory_current,
self.domdict[id].last_target
)
self.domdict[id].memory_maximum = self.xs.read('', '/local/domain/%s/memory/static-max' % str(id))
if self.domdict[id].memory_maximum:
self.domdict[id].memory_maximum = int(self.domdict[id].memory_maximum)*1024
else:
self.domdict[id].memory_maximum = self.ALL_PHYS_MEM
# the previous line used to be
# self.domdict[id].memory_maximum = domain['maxmem_kb']*1024
# but domain['maxmem_kb'] changes in self.mem_set as well, and this results in
# the memory never increasing
# in fact, the only possible case of nonexisting memory/static-max is dom0
# see #307
def clear_outdated_error_markers(self):
# Clear outdated errors
for i in self.domdict.keys():
if self.domdict[i].slow_memset_react and \
self.domdict[i].memory_actual <= self.domdict[i].last_target + self.XEN_FREE_MEM_LEFT/4:
dom_name = self.xs.read('', '/local/domain/%s/name' % str(i))
if dom_name is not None:
try:
qubes.Qubes().domains[str(dom_name)].fire_event(
'status:no-error', 'no-error',
slow_memset_react_msg)
except LookupError:
pass
self.domdict[i].slow_memset_react = False
if self.domdict[i].no_progress and \
self.domdict[i].memory_actual <= self.domdict[i].last_target + self.XEN_FREE_MEM_LEFT/4:
dom_name = self.xs.read('', '/local/domain/%s/name' % str(i))
if dom_name is not None:
try:
qubes.Qubes().domains[str(dom_name)].fire_event(
'status:no-error', 'no-error',
no_progress_msg)
except LookupError:
pass
self.domdict[i].no_progress = False
#the below works (and is fast), but then 'xm list' shows unchanged memory value
def mem_set(self, id, val):
self.log.info('mem-set domain {} to {}'.format(id, val))
self.domdict[id].last_target = val
#can happen in the middle of domain shutdown
#apparently xc.lowlevel throws exceptions too
try:
self.xc.domain_setmaxmem(int(id), int(val/1024) + 1024) # LIBXL_MAXMEM_CONSTANT=1024
self.xc.domain_set_target_mem(int(id), int(val/1024))
except:
pass
self.xs.write('', '/local/domain/' + id + '/memory/target', str(int(val/1024)))
# this is called at the end of ballooning, when we have Xen free mem already
# make sure that past mem_set will not decrease Xen free mem
def inhibit_balloon_up(self):
self.log.debug('inhibit_balloon_up()')
for i in self.domdict.keys():
dom = self.domdict[i]
if dom.memory_actual is not None and dom.memory_actual + 200*1024 < dom.last_target:
self.log.info(
'Preventing balloon up to {}'.format(dom.last_target))
self.mem_set(i, dom.memory_actual)
#perform memory ballooning, across all domains, to add "memsize" to Xen free memory
def do_balloon(self, memsize):
self.log.info('do_balloon(memsize={!r})'.format(memsize))
CHECK_PERIOD_S = 3
CHECK_MB_S = 100
niter = 0
prev_memory_actual = None
for i in self.domdict.keys():
self.domdict[i].no_progress = False
#: number of loop iterations for CHECK_PERIOD_S seconds
check_period = max(1, int((CHECK_PERIOD_S + 0.0) / self.BALOON_DELAY))
#: number of free memory bytes expected to get during CHECK_PERIOD_S
#: seconds
check_delta = CHECK_PERIOD_S * CHECK_MB_S * 1024 * 1024
#: helper array for holding free memory size, CHECK_PERIOD_S seconds
#: ago, at every loop iteration
xenfree_ring = [0] * check_period
while True:
self.log.debug('niter={:2d}'.format(niter))
self.refresh_memactual()
xenfree = self.get_free_xen_memory()
self.log.info('xenfree={!r}'.format(xenfree))
if xenfree >= memsize + self.XEN_FREE_MEM_MIN:
self.inhibit_balloon_up()
return True
# fail the request if over past CHECK_PERIOD_S seconds,
# we got less than CHECK_MB_S MB/s on average
ring_slot = niter % check_period
if niter >= check_period and xenfree < xenfree_ring[ring_slot] + check_delta:
return False
xenfree_ring[ring_slot] = xenfree
if prev_memory_actual is not None:
for i in prev_memory_actual.keys():
if prev_memory_actual[i] == self.domdict[i].memory_actual:
#domain not responding to memset requests, remove it from donors
self.domdict[i].no_progress = True
self.log.info('domain {} stuck at {}'.format(i, self.domdict[i].memory_actual))
memset_reqs = qubes.qmemman.algo.balloon(memsize + self.XEN_FREE_MEM_LEFT - xenfree, self.domdict)
self.log.info('memset_reqs={!r}'.format(memset_reqs))
if len(memset_reqs) == 0:
return False
prev_memory_actual = {}
for i in memset_reqs:
dom, mem = i
self.mem_set(dom, mem)
prev_memory_actual[dom] = self.domdict[dom].memory_actual
self.log.debug('sleeping for {} s'.format(self.BALOON_DELAY))
time.sleep(self.BALOON_DELAY)
niter = niter + 1
def refresh_meminfo(self, domid, untrusted_meminfo_key):
self.log.debug(
'refresh_meminfo(domid={}, untrusted_meminfo_key={!r})'.format(
domid, untrusted_meminfo_key))
qubes.qmemman.algo.refresh_meminfo_for_domain(
self.domdict[domid], untrusted_meminfo_key)
self.do_balance()
#is the computed balance request big enough ?
#so that we do not trash with small adjustments
def is_balance_req_significant(self, memset_reqs, xenfree):
self.log.debug(
'is_balance_req_significant(memset_reqs={}, xenfree={})'.format(
memset_reqs, xenfree))
total_memory_transfer = 0
MIN_TOTAL_MEMORY_TRANSFER = 150*1024*1024
MIN_MEM_CHANGE_WHEN_UNDER_PREF = 15*1024*1024
# If xenfree to low, return immediately
if self.XEN_FREE_MEM_LEFT - xenfree > MIN_MEM_CHANGE_WHEN_UNDER_PREF:
self.log.debug('xenfree is too low, returning')
return True
for rq in memset_reqs:
dom, mem = rq
last_target = self.domdict[dom].last_target
memory_change = mem - last_target
total_memory_transfer += abs(memory_change)
pref = qubes.qmemman.algo.prefmem(self.domdict[dom])
if last_target > 0 and last_target < pref and memory_change > MIN_MEM_CHANGE_WHEN_UNDER_PREF:
self.log.info(
'dom {} is below pref, allowing balance'.format(dom))
return True
ret = total_memory_transfer + abs(xenfree - self.XEN_FREE_MEM_LEFT) > MIN_TOTAL_MEMORY_TRANSFER
self.log.debug('is_balance_req_significant return {}'.format(ret))
return ret
def print_stats(self, xenfree, memset_reqs):
for i in self.domdict.keys():
if self.domdict[i].meminfo is not None:
self.log.info('stat: dom {!r} act={} pref={}'.format(i,
self.domdict[i].memory_actual,
qubes.qmemman.algo.prefmem(self.domdict[i])))
self.log.info('stat: xenfree={} memset_reqs={}'.format(xenfree, memset_reqs))
def do_balance(self):
self.log.debug('do_balance()')
if os.path.isfile('/var/run/qubes/do-not-membalance'):
self.log.debug('do-not-membalance file preset, returning')
return
self.refresh_memactual()
self.clear_outdated_error_markers()
xenfree = self.get_free_xen_memory()
memset_reqs = qubes.qmemman.algo.balance(xenfree - self.XEN_FREE_MEM_LEFT, self.domdict)
if not self.is_balance_req_significant(memset_reqs, xenfree):
return
self.print_stats(xenfree, memset_reqs)
prev_memactual = {}
for i in self.domdict.keys():
prev_memactual[i] = self.domdict[i].memory_actual
for rq in memset_reqs:
dom, mem = rq
# Force to always have at least 0.9*self.XEN_FREE_MEM_LEFT (some
# margin for rounding errors). Before giving memory to
# domain, ensure that others have gived it back.
# If not - wait a little.
ntries = 5
while self.get_free_xen_memory() - (mem - self.domdict[dom].memory_actual) < 0.9*self.XEN_FREE_MEM_LEFT:
self.log.debug('do_balance dom={!r} sleeping ntries={}'.format(
dom, ntries))
time.sleep(self.BALOON_DELAY)
self.refresh_memactual()
ntries -= 1
if ntries <= 0:
# Waiting haven't helped; Find which domain get stuck and
# abort balance (after distributing what we have)
for rq2 in memset_reqs:
dom2, mem2 = rq2
if dom2 == dom:
# All donors have been procesed
break
# allow some small margin
if self.domdict[dom2].memory_actual > self.domdict[dom2].last_target + self.XEN_FREE_MEM_LEFT/4:
# VM didn't react to memory request at all, remove from donors
if prev_memactual[dom2] == self.domdict[dom2].memory_actual:
self.log.warning(
'dom {!r} didnt react to memory request'
' (holds {}, requested balloon down to {})'
.format(dom2,
self.domdict[dom2].memory_actual,
mem2))
self.domdict[dom2].no_progress = True
dom_name = self.xs.read('', '/local/domain/%s/name' % str(dom2))
if dom_name is not None:
try:
qubes.Qubes().domains[str(
dom_name)].fire_event(
'status:error', 'error',
no_progress_msg)
except LookupError:
pass
else:
self.log.warning('dom {!r} still hold more'
' memory than have assigned ({} > {})'
.format(dom2,
self.domdict[dom2].memory_actual,
mem2))
self.domdict[dom2].slow_memset_react = True
dom_name = self.xs.read('', '/local/domain/%s/name' % str(dom2))
if dom_name is not None:
try:
qubes.Qubes().domains[str(
dom_name)].fire_event(
'status:error', 'error',
slow_memset_react_msg)
except LookupError:
pass
self.mem_set(dom, self.get_free_xen_memory() + self.domdict[dom].memory_actual - self.XEN_FREE_MEM_LEFT)
return
self.mem_set(dom, mem)
# for i in self.domdict.keys():
# print 'domain ', i, ' meminfo=', self.domdict[i].meminfo, 'actual mem', self.domdict[i].memory_actual
# print 'domain ', i, 'actual mem', self.domdict[i].memory_actual
# print 'xen free mem', self.get_free_xen_memory()