#!/usr/bin/python2 # -*- coding: utf-8 -*- # # The Qubes OS Project, http://www.qubes-os.org # # Copyright (C) 2010 Rafal Wojtczuk # Copyright (C) 2013 Marek Marczykowski # # 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 string # This are only defaults - can be overriden by QMemmanServer with values from # config file CACHE_FACTOR = 1.3 MIN_PREFMEM = 200*1024*1024 DOM0_MEM_BOOST = 350*1024*1024 log = logging.getLogger('qmemman.daemon.algo') #untrusted meminfo size is taken from xenstore key, thus its size is limited #so splits do not require excessive memory def parse_meminfo(untrusted_meminfo): untrusted_dict = {} #split meminfo contents into lines untrusted_lines = string.split(untrusted_meminfo,"\n") for untrusted_lines_iterator in untrusted_lines: #split a single meminfo line into words untrusted_words = string.split(untrusted_lines_iterator) if len(untrusted_words) >= 2: untrusted_dict[string.rstrip(untrusted_words[0], ":")] = untrusted_words[1] return untrusted_dict def is_meminfo_suspicious(domain, untrusted_meminfo): log.debug('is_meminfo_suspicious(' 'domain={!r}, untrusted_meminfo={!r})'.format( domain, untrusted_meminfo)) ret = False #check whether the required keys exist and are not negative try: for i in ('MemTotal', 'MemFree', 'Buffers', 'Cached', 'SwapTotal', 'SwapFree'): val = int(untrusted_meminfo[i])*1024 if (val < 0): ret = True untrusted_meminfo[i] = val except: ret = True if not ret and untrusted_meminfo['SwapTotal'] < untrusted_meminfo['SwapFree']: ret = True if not ret and untrusted_meminfo['MemTotal'] < untrusted_meminfo['MemFree'] + untrusted_meminfo['Cached'] + untrusted_meminfo['Buffers']: ret = True #we could also impose some limits on all the above values #but it has little purpose - all the domain can gain by passing e.g. #very large SwapTotal is that it will be assigned all free Xen memory #it can be achieved with legal values, too, and it will not allow to #starve existing domains, by design if ret: log.warning('suspicious meminfo for domain {!r}' ' memory_actual={!r} untrusted_meminfo={!r}'.format(domain.id, domain.memory_actual, untrusted_meminfo)) return ret #called when a domain updates its 'meminfo' xenstore key def refresh_meminfo_for_domain(domain, untrusted_xenstore_key): untrusted_meminfo = parse_meminfo(untrusted_xenstore_key) if untrusted_meminfo is None: domain.meminfo = None return #sanitize start if is_meminfo_suspicious(domain, untrusted_meminfo): #sanitize end domain.meminfo = None domain.mem_used = None else: #sanitized, can assign domain.meminfo = untrusted_meminfo domain.mem_used = domain.meminfo['MemTotal'] - domain.meminfo['MemFree'] - domain.meminfo['Cached'] - domain.meminfo['Buffers'] + domain.meminfo['SwapTotal'] - domain.meminfo['SwapFree'] def prefmem(domain): #dom0 is special, as it must have large cache, for vbds. Thus, give it a special boost if domain.id == '0': return min(domain.mem_used*CACHE_FACTOR + 350*1024*1024, domain.memory_maximum) return max(min(domain.mem_used*CACHE_FACTOR, domain.memory_maximum), MIN_PREFMEM) def memory_needed(domain): #do not change #in balance(), "distribute total_available_memory proportionally to mempref" relies on this exact formula ret = prefmem(domain) - domain.memory_actual return ret #prepare list of (domain, memory_target) pairs that need to be passed #to "xm memset" equivalent in order to obtain "memsize" of memory #return empty list when the request cannot be satisfied def balloon(memsize, domain_dictionary): log.debug('balloon(memsize={!r}, domain_dictionary={!r})'.format( memsize, domain_dictionary)) REQ_SAFETY_NET_FACTOR = 1.05 donors = list() request = list() available = 0 for i in domain_dictionary.keys(): if domain_dictionary[i].meminfo is None: continue if domain_dictionary[i].no_progress: continue need = memory_needed(domain_dictionary[i]) if need < 0: log.info('balloon: dom {} has actual memory {}'.format(i, domain_dictionary[i].memory_actual)) donors.append((i,-need)) available-=need log.info('req={} avail={} donors={!r}'.format(memsize, available, donors)) if available domain_dictionary[i].memory_maximum: left_memory += target-domain_dictionary[i].memory_maximum target = domain_dictionary[i].memory_maximum else: # count domains which can accept more memory acceptors_count += 1 target_memory[i] = target # distribute left memory across all acceptors while left_memory > 0 and acceptors_count > 0: log.info('left_memory={} acceptors_count={}'.format( left_memory, acceptors_count)) new_left_memory = 0 new_acceptors_count = acceptors_count for i in target_memory.keys(): target = target_memory[i] if target < domain_dictionary[i].memory_maximum: memory_bonus = int(0.999*(left_memory/acceptors_count)) if target+memory_bonus >= domain_dictionary[i].memory_maximum: new_left_memory += target+memory_bonus - domain_dictionary[i].memory_maximum target = domain_dictionary[i].memory_maximum new_acceptors_count -= 1 else: target += memory_bonus target_memory[i] = target left_memory = new_left_memory acceptors_count = new_acceptors_count # split target_memory dictionary to donors and acceptors # this is needed to first get memory from donors and only then give it to acceptors donors_rq = list() acceptors_rq = list() for i in target_memory.keys(): target = target_memory[i] if (target < domain_dictionary[i].memory_actual): donors_rq.append((i, target)) else: acceptors_rq.append((i, target)) # print 'balance(enough): xen_free_memory=', xen_free_memory, 'requests:', donors_rq + acceptors_rq return donors_rq + acceptors_rq #when not enough mem to make everyone be above prefmem, make donors be at prefmem, and #redistribute anything left between acceptors def balance_when_low_on_memory(domain_dictionary, xen_free_memory, total_mem_pref_acceptors, donors, acceptors): log.debug('balance_when_low_on_memory(xen_free_memory={!r}, ' 'total_mem_pref_acceptors={!r}, donors={!r}, acceptors={!r})'.format( xen_free_memory, total_mem_pref_acceptors, donors, acceptors)) donors_rq = list() acceptors_rq = list() squeezed_mem = xen_free_memory for i in donors: avail = -memory_needed(domain_dictionary[i]) if avail < 10*1024*1024: #probably we have already tried making it exactly at prefmem, give up continue squeezed_mem -= avail donors_rq.append((i, prefmem(domain_dictionary[i]))) #the below can happen if initially xen free memory is below 50M if squeezed_mem < 0: return donors_rq for i in acceptors: scale = 1.0*prefmem(domain_dictionary[i])/total_mem_pref_acceptors target_nonint = domain_dictionary[i].memory_actual + scale*squeezed_mem #do not try to give more memory than static max target = min(int(0.999*target_nonint), domain_dictionary[i].memory_maximum) acceptors_rq.append((i, target)) # print 'balance(low): xen_free_memory=', xen_free_memory, 'requests:', donors_rq + acceptors_rq return donors_rq + acceptors_rq #redistribute memory across domains #called when one of domains update its 'meminfo' xenstore key #return the list of (domain, memory_target) pairs to be passed to #"xm memset" equivalent def balance(xen_free_memory, domain_dictionary): log.debug('balance(xen_free_memory={!r}, domain_dictionary={!r})'.format( xen_free_memory, domain_dictionary)) #sum of all memory requirements - in other words, the difference between #memory required to be added to domains (acceptors) to make them be at their #preferred memory, and memory that can be taken from domains (donors) that #can provide memory. So, it can be negative when plenty of memory. total_memory_needed = 0 #sum of memory preferences of all domains total_mem_pref = 0 #sum of memory preferences of all domains that require more memory total_mem_pref_acceptors = 0 donors = list() # domains that can yield memory acceptors = list() # domains that require more memory #pass 1: compute the above "total" values for i in domain_dictionary.keys(): if domain_dictionary[i].meminfo is None: continue if domain_dictionary[i].no_progress: continue need = memory_needed(domain_dictionary[i]) # print 'domain' , i, 'act/pref', domain_dictionary[i].memory_actual, prefmem(domain_dictionary[i]), 'need=', need if need < 0 or domain_dictionary[i].memory_actual >= domain_dictionary[i].memory_maximum: donors.append(i) else: acceptors.append(i) total_mem_pref_acceptors += prefmem(domain_dictionary[i]) total_memory_needed += need total_mem_pref += prefmem(domain_dictionary[i]) total_available_memory = xen_free_memory - total_memory_needed if total_available_memory > 0: return balance_when_enough_memory(domain_dictionary, xen_free_memory, total_mem_pref, total_available_memory) else: return balance_when_low_on_memory(domain_dictionary, xen_free_memory, total_mem_pref_acceptors, donors, acceptors)