core-admin/dom0/qmemman/qmemman_server.py
Rafal Wojtczuk eb6755e93c qmemman: fix locking
We want balance() to wait on a lock even after balloon() has finished,
until socket client has closed.
2010-08-30 14:50:48 +02:00

131 lines
3.8 KiB
Python
Executable File

#!/usr/bin/python
import SocketServer
import thread
import time
import xen.lowlevel.xs
import sys
import os
from qmemman import SystemState
system_state = SystemState()
global_lock = thread.allocate_lock()
additional_balance_delay = 0
def only_in_first_list(l1, l2):
ret=[]
for i in l1:
if not i in l2:
ret.append(i)
return ret
def get_req_node(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.handle = xen.lowlevel.xs.xs()
self.handle.watch('/local/domain', WatchType(XS_Watcher.dom_list_change, None))
self.watch_token_dict = {}
def dom_list_change(self, param):
curr = self.handle.ls('', '/local/domain')
if curr == None:
return
global_lock.acquire()
for i in only_in_first_list(curr, self.watch_token_dict.keys()):
watch = WatchType(XS_Watcher.request, i)
self.watch_token_dict[i] = watch
self.handle.watch(get_req_node(i), watch)
system_state.add_domain(i)
for i in only_in_first_list(self.watch_token_dict.keys(), curr):
self.handle.unwatch(get_req_node(i), self.watch_token_dict[i])
self.watch_token_dict.pop(i)
system_state.del_domain(i)
global_lock.release()
def request(self, domain_id):
ret = self.handle.read('', get_req_node(domain_id))
if ret == None or ret == '':
return
global_lock.acquire()
system_state.refresh_meminfo(domain_id, ret)
global_lock.release()
def watch_loop(self):
# sys.stderr = file('/var/log/qubes/qfileexchgd.errors', 'a')
while True:
result = self.handle.read_watch()
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):
global additional_balance_delay
got_lock = False
# self.request is the TCP socket connected to the client
while True:
self.data = self.request.recv(1024).strip()
if len(self.data) == 0:
print 'EOF'
if got_lock:
global_lock.release()
return
if got_lock:
print 'Second request over qmemman.sock ?'
return
global_lock.acquire()
got_lock = True
if system_state.do_balloon(int(self.data)):
resp = "OK\n"
additional_balance_delay = 5
else:
resp = "FAIL\n"
self.request.send(resp)
def start_server():
SOCK_PATH='/var/run/qubes/qmemman.sock'
try:
os.unlink(SOCK_PATH)
except:
pass
os.umask(0)
server = SocketServer.UnixStreamServer(SOCK_PATH, QMemmanReqHandler)
os.umask(077)
server.serve_forever()
def start_balancer():
global additional_balance_delay
while True:
time.sleep(1)
if additional_balance_delay != 0:
print 'waiting additional_balance_delay to allow VM to start'
time.sleep(additional_balance_delay)
additional_balance_delay = 0
global_lock.acquire()
if additional_balance_delay == 0:
system_state.do_balance()
global_lock.release()
class QMemmanServer:
@staticmethod
def main():
thread.start_new_thread(start_server, tuple([]))
thread.start_new_thread(start_balancer, tuple([]))
XS_Watcher().watch_loop()