core-admin/qmemman/qmemman_server.py
Marek Marczykowski-Górecki 181eb3e764
qmemman: handle memory assigned to VM but not yet used
When VM got some memory assigned, balloon driver may not pick it up
immediatelly and the memory will still be seen as "free" by Xen, but VM
can use (request) it at any time. Qmemman needs to take care of such
memory (exclude it from "free" pool), otherwise it would redistribute it
to other domains, allowing the original domain to drain Xen memory pool.

Do this by redefining DomainState.memory_actual - it is now amount of
memory available to the VM (currently used, or possibly used). Then
calculate free memory by subtracting memory allocated but not used
(memory_target-memory_current).

Fixes QubesOS/qubes-issues#1389
2016-01-06 00:40:10 +01:00

267 lines
8.9 KiB
Python
Executable File

#!/usr/bin/python2
# -*- coding: utf-8 -*-
#
# The Qubes OS Project, http://www.qubes-os.org
#
# Copyright (C) 2010 Rafal Wojtczuk <rafal@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 SocketServer
import thread
import time
import xen.lowlevel.xs
import sys
import os
import socket
from qmemman import SystemState
import qmemman_algo
from ConfigParser import SafeConfigParser
from optparse import OptionParser
from qubesutils import parse_size
import logging
import logging.handlers
config_path = '/etc/qubes/qmemman.conf'
SOCK_PATH='/var/run/qubes/qmemman.sock'
LOG_PATH='/var/log/qubes/qmemman.log'
system_state = SystemState()
global_lock = thread.allocate_lock()
def only_in_first_list(l1, l2):
ret=[]
for i in l1:
if not i in l2:
ret.append(i)
return ret
def get_domain_meminfo_key(domain_id):
return '/local/domain/'+domain_id+'/memory/meminfo'
class WatchType:
def __init__(self, fn, param):
self.fn = fn
self.param = param
class XS_Watcher:
def __init__(self):
self.log = logging.getLogger('qmemman.daemon.xswatcher')
self.log.debug('XS_Watcher()')
self.handle = xen.lowlevel.xs.xs()
self.handle.watch('@introduceDomain', WatchType(XS_Watcher.domain_list_changed, None))
self.handle.watch('@releaseDomain', WatchType(XS_Watcher.domain_list_changed, None))
self.watch_token_dict = {}
def domain_list_changed(self, param):
self.log.debug('domain_list_changed(param={!r})'.format(param))
curr = self.handle.ls('', '/local/domain')
if curr == None:
return
# check if domain is really there, it may happen that some empty
# directories are left in xenstore
curr = filter(
lambda x:
self.handle.read('',
'/local/domain/{}/domid'.format(x)
) is not None,
curr
)
self.log.debug('curr={!r}'.format(curr))
self.log.debug('acquiring global_lock')
global_lock.acquire()
self.log.debug('global_lock acquired')
for i in only_in_first_list(curr, self.watch_token_dict.keys()):
#new domain has been created
watch = WatchType(XS_Watcher.meminfo_changed, i)
self.watch_token_dict[i] = watch
self.handle.watch(get_domain_meminfo_key(i), watch)
system_state.add_domain(i)
for i in only_in_first_list(self.watch_token_dict.keys(), curr):
#domain destroyed
self.handle.unwatch(get_domain_meminfo_key(i), self.watch_token_dict[i])
self.watch_token_dict.pop(i)
system_state.del_domain(i)
global_lock.release()
self.log.debug('global_lock released')
system_state.do_balance()
def meminfo_changed(self, domain_id):
self.log.debug('meminfo_changed(domain_id={!r})'.format(domain_id))
untrusted_meminfo_key = self.handle.read('', get_domain_meminfo_key(domain_id))
if untrusted_meminfo_key == None or untrusted_meminfo_key == '':
return
self.log.debug('acquiring global_lock')
global_lock.acquire()
self.log.debug('global_lock acquired')
system_state.refresh_meminfo(domain_id, untrusted_meminfo_key)
global_lock.release()
self.log.debug('global_lock released')
def watch_loop(self):
self.log.debug('watch_loop()')
while True:
result = self.handle.read_watch()
self.log.debug('watch_loop result={!r}'.format(result))
token = result[1]
token.fn(self, token.param)
class QMemmanReqHandler(SocketServer.BaseRequestHandler):
"""
The RequestHandler class for our server.
It is instantiated once per connection to the server, and must
override the handle() method to implement communication to the
client.
"""
def handle(self):
self.log = logging.getLogger('qmemman.daemon.reqhandler')
got_lock = False
# self.request is the TCP socket connected to the client
while True:
self.data = self.request.recv(1024).strip()
self.log.debug('data={!r}'.format(self.data))
if len(self.data) == 0:
self.log.info('EOF')
# FIXME: there is a race condition here: if XS_Watcher will
# handle meminfo event before @introduceDomain, it will use
# incomplete domain list for that and may redistribute memory
# allocated to some VM, but not yet used (see #1389).
# To fix that, system_state should be updated (refresh domain
# list) before releasing the lock, but in the current code
# layout XS_Watcher instance isn't available here,
# so xenstore watches would not be registered
if got_lock:
global_lock.release()
self.log.debug('global_lock released')
return
# XXX something is wrong here: return without release?
if got_lock:
self.log.warning('Second request over qmemman.sock?')
return
self.log.debug('acquiring global_lock')
global_lock.acquire()
self.log.debug('global_lock acquired')
got_lock = True
if system_state.do_balloon(int(self.data)):
resp = "OK\n"
else:
resp = "FAIL\n"
self.log.debug('resp={!r}'.format(resp))
self.request.send(resp)
# XXX no release of lock?
def start_server(server):
server.serve_forever()
class QMemmanServer:
@staticmethod
def main():
# setup logging
ha_syslog = logging.handlers.SysLogHandler('/dev/log')
ha_syslog.setFormatter(
logging.Formatter('%(name)s[%(process)d]: %(message)s'))
logging.root.addHandler(ha_syslog)
# leave log for backwards compatibility
ha_file = logging.FileHandler(LOG_PATH)
ha_file.setFormatter(
logging.Formatter('%(asctime)s %(name)s[%(process)d]: %(message)s'))
logging.root.addHandler(ha_file)
log = logging.getLogger('qmemman.daemon')
usage = "usage: %prog [options]"
parser = OptionParser(usage)
parser.add_option("-c", "--config", action="store", dest="config", default=config_path)
parser.add_option("-d", "--debug", action="store_true", dest="debug",
default=False, help="Enable debugging")
(options, args) = parser.parse_args()
if options.debug:
logging.root.setLevel(logging.DEBUG)
# close io
sys.stdin.close()
sys.stdout.close()
sys.stderr.close()
config = SafeConfigParser({
'vm-min-mem': str(qmemman_algo.MIN_PREFMEM),
'dom0-mem-boost': str(qmemman_algo.DOM0_MEM_BOOST),
'cache-margin-factor': str(qmemman_algo.CACHE_FACTOR)
})
config.read(options.config)
if config.has_section('global'):
qmemman_algo.MIN_PREFMEM = parse_size(config.get('global', 'vm-min-mem'))
qmemman_algo.DOM0_MEM_BOOST = parse_size(config.get('global', 'dom0-mem-boost'))
qmemman_algo.CACHE_FACTOR = config.getfloat('global', 'cache-margin-factor')
log.info('MIN_PREFMEM={qmemman_algo.MIN_PREFMEM}'
' DOM0_MEM_BOOST={qmemman_algo.DOM0_MEM_BOOST}'
' CACHE_FACTOR={qmemman_algo.CACHE_FACTOR}'.format(
qmemman_algo=qmemman_algo))
try:
os.unlink(SOCK_PATH)
except:
pass
log.debug('instantiating server')
os.umask(0)
server = SocketServer.UnixStreamServer(SOCK_PATH, QMemmanReqHandler)
os.umask(077)
# notify systemd
nofity_socket = os.getenv('NOTIFY_SOCKET')
if nofity_socket:
log.debug('notifying systemd')
s = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
if nofity_socket.startswith('@'):
nofity_socket = '\0%s' % nofity_socket[1:]
s.connect(nofity_socket)
s.sendall("READY=1")
s.close()
thread.start_new_thread(start_server, tuple([server]))
XS_Watcher().watch_loop()