4cf6a93b5b
Add logging more info about each domain state: - last requested target - no_progress and slow_memset_react flags This makes it unnecessary to log separately when those flags are cleared.
321 lines
12 KiB
Python
321 lines
12 KiB
Python
# pylint: skip-file
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#
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# The Qubes OS Project, http://www.qubes-os.org
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#
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# Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
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# Copyright (C) 2013 Marek Marczykowski <marmarek@invisiblethingslab.com>
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#
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# This library is free software; you can redistribute it and/or
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# modify it under the terms of the GNU Lesser General Public
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# License as published by the Free Software Foundation; either
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# version 2.1 of the License, or (at your option) any later version.
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#
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# This library is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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# Lesser General Public License for more details.
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#
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# You should have received a copy of the GNU Lesser General Public
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# License along with this library; if not, see <https://www.gnu.org/licenses/>.
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#
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import logging
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import string
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# This are only defaults - can be overridden by QMemmanServer with values from
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# config file
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CACHE_FACTOR = 1.3
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MIN_PREFMEM = 200 * 1024 * 1024
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DOM0_MEM_BOOST = 350 * 1024 * 1024
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log = logging.getLogger('qmemman.daemon.algo')
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# untrusted meminfo size is taken from xenstore key, thus its size is limited
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# so splits do not require excessive memory
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def sanitize_and_parse_meminfo(untrusted_meminfo):
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if not untrusted_meminfo:
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return None
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# new syntax - just one int
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try:
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if int(untrusted_meminfo) >= 0:
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return int(untrusted_meminfo) * 1024
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except ValueError:
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pass
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untrusted_meminfo = untrusted_meminfo.decode('ascii', errors='strict')
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# not new syntax - try the old one
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untrusted_dict = {}
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# split meminfo contents into lines
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untrusted_lines = untrusted_meminfo.split("\n")
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for untrusted_lines_iterator in untrusted_lines:
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# split a single meminfo line into words
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untrusted_words = untrusted_lines_iterator.split()
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if len(untrusted_words) >= 2:
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untrusted_dict[untrusted_words[0].rstrip(":")] = \
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untrusted_words[1]
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# sanitize start
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if not is_meminfo_suspicious(untrusted_dict):
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# sanitize end
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meminfo = untrusted_dict
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return (meminfo['MemTotal'] -
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meminfo['MemFree'] - meminfo['Cached'] - meminfo['Buffers'] +
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meminfo['SwapTotal'] - meminfo['SwapFree']) * 1024
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return None
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def is_meminfo_suspicious(untrusted_meminfo):
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log.debug('is_meminfo_suspicious('
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'untrusted_meminfo={!r})'.format(untrusted_meminfo))
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ret = False
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# check whether the required keys exist and are not negative
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try:
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for i in ('MemTotal', 'MemFree', 'Buffers', 'Cached',
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'SwapTotal', 'SwapFree'):
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val = int(untrusted_meminfo[i])
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if val < 0:
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ret = True
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untrusted_meminfo[i] = val
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except:
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ret = True
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if untrusted_meminfo['SwapTotal'] < untrusted_meminfo['SwapFree']:
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ret = True
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if untrusted_meminfo['MemTotal'] < \
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untrusted_meminfo['MemFree'] + \
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untrusted_meminfo['Cached'] + untrusted_meminfo[
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'Buffers']:
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ret = True
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# we could also impose some limits on all the above values
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# but it has little purpose - all the domain can gain by passing e.g.
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# very large SwapTotal is that it will be assigned all free Xen memory
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# it can be achieved with legal values, too, and it will not allow to
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# starve existing domains, by design
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if ret:
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log.warning('suspicious meminfo untrusted_meminfo={!r}'.format(
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untrusted_meminfo))
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return ret
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# called when a domain updates its 'meminfo' xenstore key
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def refresh_meminfo_for_domain(domain, untrusted_xenstore_key):
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domain.mem_used = sanitize_and_parse_meminfo(untrusted_xenstore_key)
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def prefmem(domain):
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# dom0 is special, as it must have large cache, for vbds. Thus, give it
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# a special boost
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if domain.id == '0':
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return min(domain.mem_used * CACHE_FACTOR + DOM0_MEM_BOOST,
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domain.memory_maximum)
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return max(min(domain.mem_used * CACHE_FACTOR, domain.memory_maximum),
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MIN_PREFMEM)
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def memory_needed(domain):
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# do not change
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# in balance(), "distribute total_available_memory proportionally to
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# mempref" relies on this exact formula
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ret = prefmem(domain) - domain.memory_actual
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return ret
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# prepare list of (domain, memory_target) pairs that need to be passed
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# to "xm memset" equivalent in order to obtain "memsize" of memory
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# return empty list when the request cannot be satisfied
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def balloon(memsize, domain_dictionary):
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log.debug('balloon(memsize={!r}, domain_dictionary={!r})'.format(
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memsize, domain_dictionary))
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REQ_SAFETY_NET_FACTOR = 1.05
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donors = list()
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request = list()
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available = 0
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for i in domain_dictionary.keys():
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if domain_dictionary[i].mem_used is None:
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continue
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if domain_dictionary[i].no_progress:
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continue
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need = memory_needed(domain_dictionary[i])
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if need < 0:
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log.info('balloon: dom {} has actual memory {}'.format(i,
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domain_dictionary[i].memory_actual))
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donors.append((i, -need))
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available -= need
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log.info('req={} avail={} donors={!r}'.format(memsize, available, donors))
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if available < memsize:
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return ()
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scale = 1.0 * memsize / available
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for donors_iter in donors:
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dom_id, mem = donors_iter
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memborrowed = mem * scale * REQ_SAFETY_NET_FACTOR
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log.info('borrow {} from {}'.format(memborrowed, dom_id))
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memtarget = int(domain_dictionary[dom_id].memory_actual - memborrowed)
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request.append((dom_id, memtarget))
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return request
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# REQ_SAFETY_NET_FACTOR is a bit greater that 1. So that if the domain
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# yields a bit less than requested, due to e.g. rounding errors, we will not
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# get stuck. The surplus will return to the VM during "balance" call.
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# redistribute positive "total_available_memory" of memory between domains,
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# proportionally to prefmem
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def balance_when_enough_memory(domain_dictionary,
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xen_free_memory, total_mem_pref, total_available_memory):
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log.info('balance_when_enough_memory(xen_free_memory={!r}, '
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'total_mem_pref={!r}, total_available_memory={!r})'.format(
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xen_free_memory, total_mem_pref, total_available_memory))
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target_memory = {}
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# memory not assigned because of static max
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left_memory = 0
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acceptors_count = 0
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for i in domain_dictionary.keys():
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if domain_dictionary[i].mem_used is None:
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continue
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if domain_dictionary[i].no_progress:
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continue
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# distribute total_available_memory proportionally to mempref
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scale = 1.0 * prefmem(domain_dictionary[i]) / total_mem_pref
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target_nonint = prefmem(
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domain_dictionary[i]) + scale * total_available_memory
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# prevent rounding errors
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target = int(0.999 * target_nonint)
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# do not try to give more memory than static max
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if target > domain_dictionary[i].memory_maximum:
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left_memory += target - domain_dictionary[i].memory_maximum
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target = domain_dictionary[i].memory_maximum
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else:
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# count domains which can accept more memory
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acceptors_count += 1
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target_memory[i] = target
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# distribute left memory across all acceptors
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while left_memory > 0 and acceptors_count > 0:
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log.info('left_memory={} acceptors_count={}'.format(
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left_memory, acceptors_count))
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new_left_memory = 0
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new_acceptors_count = acceptors_count
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for i in target_memory.keys():
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target = target_memory[i]
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if target < domain_dictionary[i].memory_maximum:
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memory_bonus = int(0.999 * (left_memory / acceptors_count))
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if target + memory_bonus >= domain_dictionary[i].memory_maximum:
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new_left_memory += target + memory_bonus - \
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domain_dictionary[i].memory_maximum
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target = domain_dictionary[i].memory_maximum
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new_acceptors_count -= 1
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else:
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target += memory_bonus
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target_memory[i] = target
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left_memory = new_left_memory
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acceptors_count = new_acceptors_count
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# split target_memory dictionary to donors and acceptors
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# this is needed to first get memory from donors and only then give it
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# to acceptors
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donors_rq = list()
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acceptors_rq = list()
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for i in target_memory.keys():
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target = target_memory[i]
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if target < domain_dictionary[i].memory_actual:
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donors_rq.append((i, target))
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else:
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acceptors_rq.append((i, target))
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# print 'balance(enough): xen_free_memory=', xen_free_memory, \
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# 'requests:', donors_rq + acceptors_rq
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return donors_rq + acceptors_rq
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# when not enough mem to make everyone be above prefmem, make donors be at
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# prefmem, and redistribute anything left between acceptors
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def balance_when_low_on_memory(domain_dictionary,
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xen_free_memory, total_mem_pref_acceptors, donors, acceptors):
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log.info('balance_when_low_on_memory(xen_free_memory={!r}, '
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'total_mem_pref_acceptors={!r}, donors={!r}, acceptors={!r})'.format(
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xen_free_memory, total_mem_pref_acceptors, donors, acceptors))
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donors_rq = list()
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acceptors_rq = list()
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squeezed_mem = xen_free_memory
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for i in donors:
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avail = -memory_needed(domain_dictionary[i])
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if avail < 10 * 1024 * 1024:
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# probably we have already tried making it exactly at prefmem,
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# give up
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continue
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squeezed_mem -= avail
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donors_rq.append((i, prefmem(domain_dictionary[i])))
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# the below can happen if initially xen free memory is below 50M
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if squeezed_mem < 0:
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return donors_rq
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for i in acceptors:
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scale = 1.0 * prefmem(domain_dictionary[i]) / total_mem_pref_acceptors
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target_nonint = \
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domain_dictionary[i].memory_actual + scale * squeezed_mem
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# do not try to give more memory than static max
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target = \
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min(int(0.999 * target_nonint), domain_dictionary[i].memory_maximum)
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acceptors_rq.append((i, target))
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# print 'balance(low): xen_free_memory=', xen_free_memory, 'requests:',
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# donors_rq + acceptors_rq
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return donors_rq + acceptors_rq
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# redistribute memory across domains
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# called when one of domains update its 'meminfo' xenstore key
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# return the list of (domain, memory_target) pairs to be passed to
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# "xm memset" equivalent
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def balance(xen_free_memory, domain_dictionary):
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log.debug('balance(xen_free_memory={!r}, domain_dictionary={!r})'.format(
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xen_free_memory, domain_dictionary))
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# sum of all memory requirements - in other words, the difference between
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# memory required to be added to domains (acceptors) to make them be
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# at their preferred memory, and memory that can be taken from domains
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# (donors) that can provide memory. So, it can be negative when plenty
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# of memory.
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total_memory_needed = 0
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# sum of memory preferences of all domains
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total_mem_pref = 0
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# sum of memory preferences of all domains that require more memory
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total_mem_pref_acceptors = 0
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donors = list() # domains that can yield memory
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acceptors = list() # domains that require more memory
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# pass 1: compute the above "total" values
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for i in domain_dictionary.keys():
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if domain_dictionary[i].mem_used is None:
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continue
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if domain_dictionary[i].no_progress:
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continue
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need = memory_needed(domain_dictionary[i])
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# print 'domain' , i, 'act/pref', \
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# domain_dictionary[i].memory_actual, prefmem(domain_dictionary[i]), \
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# 'need=', need
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if need < 0 or domain_dictionary[i].memory_actual >= \
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domain_dictionary[i].memory_maximum:
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donors.append(i)
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else:
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acceptors.append(i)
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total_mem_pref_acceptors += prefmem(domain_dictionary[i])
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total_memory_needed += need
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total_mem_pref += prefmem(domain_dictionary[i])
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total_available_memory = xen_free_memory - total_memory_needed
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if total_available_memory > 0:
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return balance_when_enough_memory(domain_dictionary, xen_free_memory,
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total_mem_pref, total_available_memory)
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else:
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return balance_when_low_on_memory(domain_dictionary, xen_free_memory,
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total_mem_pref_acceptors, donors, acceptors)
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