def network(op):
"""Call a network control script.
@param op: operation (start, stop)
"""
if op not in ["start", "stop"]:
raise ValueError("Invalid operation: " + op)
script = XendRoot.instance().get_network_script()
if script:
script.insert(1, op)
os.spawnv(os.P_WAIT, script[0], script)
def network(op):
"""Call a network control script.
@param op: operation (start, stop)
"""
if op not in ['start', 'stop']:
raise ValueError('Invalid operation: ' + op)
script = XendRoot.instance().get_network_script()
if script:
script.insert(1, op)
os.spawnv(os.P_WAIT, script[0], script)
def free(required):
"""Balloon out memory from the privileged domain so that there is the
specified required amount (in KiB) free.
"""
# We check whether there is enough free memory, and if not, instruct dom0
# to balloon out to free some up. Memory freed by a destroyed domain may
# not appear in the free_memory field immediately, because it needs to be
# scrubbed before it can be released to the free list, which is done
# asynchronously by Xen; ballooning is asynchronous also. No matter where
# we expect the free memory to come from, therefore, we need to wait for
# it to become available.
#
# We are not allowed to balloon below dom0_min_mem, or if dom0_min_mem
# is 0, we cannot balloon at all. Memory can still become available
# through a rebooting domain, however.
#
# Eventually, we time out (presumably because there really isn't enough
# free memory).
#
# We don't want to set the memory target (triggering a watch) when that
# has already been done, but we do want to respond to changing memory
# usage, so we recheck the required alloc each time around the loop, but
# track the last used value so that we don't trigger too many watches.
need_mem = (required + 1023) / 1024 + BALLOON_OUT_SLACK
xroot = XendRoot.instance()
xc = xen.lowlevel.xc.xc()
try:
dom0_min_mem = xroot.get_dom0_min_mem()
retries = 0
sleep_time = SLEEP_TIME_GROWTH
last_new_alloc = None
while retries < RETRY_LIMIT:
free_mem = xc.physinfo()['free_memory']
if free_mem >= need_mem:
log.debug("Balloon: free %d; need %d; done.", free_mem,
need_mem)
return
if retries == 0:
log.debug("Balloon: free %d; need %d.", free_mem, need_mem)
if dom0_min_mem > 0:
dom0_alloc = get_dom0_current_alloc()
new_alloc = dom0_alloc - (need_mem - free_mem)
if (new_alloc >= dom0_min_mem and
new_alloc != last_new_alloc):
log.debug("Balloon: setting dom0 target to %d.",
new_alloc)
dom0 = XendDomain.instance().privilegedDomain()
dom0.setMemoryTarget(new_alloc)
last_new_alloc = new_alloc
# Continue to retry, waiting for ballooning.
time.sleep(sleep_time)
retries += 1
sleep_time += SLEEP_TIME_GROWTH
# Not enough memory; diagnose the problem.
if dom0_min_mem == 0:
raise VmError(('Not enough free memory and dom0_min_mem is 0, so '
'I cannot release any more. I need %d MiB but '
'only have %d.') %
(need_mem, free_mem))
elif new_alloc < dom0_min_mem:
raise VmError(
('I need %d MiB, but dom0_min_mem is %d and shrinking to '
'%d MiB would leave only %d MiB free.') %
(need_mem, dom0_min_mem, dom0_min_mem,
free_mem + dom0_alloc - dom0_min_mem))
else:
raise VmError('The privileged domain did not balloon!')
finally:
del xc
def free(required):
"""Balloon out memory from the privileged domain so that there is the
specified required amount (in KiB) free.
"""
# We check whether there is enough free memory, and if not, instruct dom0
# to balloon out to free some up. Memory freed by a destroyed domain may
# not appear in the free_memory field immediately, because it needs to be
# scrubbed before it can be released to the free list, which is done
# asynchronously by Xen; ballooning is asynchronous also. No matter where
# we expect the free memory to come from, therefore, we need to wait for
# it to become available.
#
# We are not allowed to balloon below dom0_min_mem, or if dom0_min_mem
# is 0, we cannot balloon at all. Memory can still become available
# through a rebooting domain, however.
#
# Eventually, we time out (presumably because there really isn't enough
# free memory).
#
# We don't want to set the memory target (triggering a watch) when that
# has already been done, but we do want to respond to changing memory
# usage, so we recheck the required alloc each time around the loop, but
# track the last used value so that we don't trigger too many watches.
need_mem = (required + 1023) / 1024 + BALLOON_OUT_SLACK
xroot = XendRoot.instance()
xc = xen.lowlevel.xc.xc()
try:
dom0_min_mem = xroot.get_dom0_min_mem()
retries = 0
sleep_time = SLEEP_TIME_GROWTH
last_new_alloc = None
while retries < RETRY_LIMIT:
free_mem = xc.physinfo()['free_memory']
if free_mem >= need_mem:
log.debug("Balloon: free %d; need %d; done.", free_mem,
need_mem)
return
if retries == 0:
log.debug("Balloon: free %d; need %d.", free_mem, need_mem)
if dom0_min_mem > 0:
dom0_alloc = get_dom0_current_alloc()
new_alloc = dom0_alloc - (need_mem - free_mem)
if (new_alloc >= dom0_min_mem and new_alloc != last_new_alloc):
log.debug("Balloon: setting dom0 target to %d.", new_alloc)
dom0 = XendDomain.instance().privilegedDomain()
dom0.setMemoryTarget(new_alloc)
last_new_alloc = new_alloc
# Continue to retry, waiting for ballooning.
time.sleep(sleep_time)
retries += 1
sleep_time += SLEEP_TIME_GROWTH
# Not enough memory; diagnose the problem.
if dom0_min_mem == 0:
raise VmError(('Not enough free memory and dom0_min_mem is 0, so '
'I cannot release any more. I need %d MiB but '
'only have %d.') % (need_mem, free_mem))
elif new_alloc < dom0_min_mem:
raise VmError(
('I need %d MiB, but dom0_min_mem is %d and shrinking to '
'%d MiB would leave only %d MiB free.') %
(need_mem, dom0_min_mem, dom0_min_mem,
free_mem + dom0_alloc - dom0_min_mem))
else:
raise VmError('The privileged domain did not balloon!')
finally:
del xc
