+ self.dc_alloc_cu -= self._get_flavor(d).get("compute")
+
+ def _free_mem(self, d):
+ """
+ Free resources.
+ :param d: container
+ :return:
+ """
+ self.dc_alloc_mu -= self._get_flavor(d).get("memory")
+
+ def _apply_limits(self):
+ """
+ Recalculate real resource limits for all allocated containers and apply them
+ to their cgroups.
+ We have to recalculate for all containers to allow e.g. over provisioning models.
+ :return:
+ """
+ for d in self._allocated_compute_instances.itervalues():
+ if not self.deactivate_cpu_limit:
+ self._apply_cpu_limits(d)
+ if not self.deactivate_mem_limit:
+ self._apply_mem_limits(d)
+
+ def _apply_cpu_limits(self, d):
+ """
+ Calculate real CPU limit (CFS bandwidth) and apply.
+ :param d: container
+ :return:
+ """
+ number_cu = self._get_flavor(d).get("compute")
+ # calculate cpu time fraction of a single compute unit
+ self.single_cu = self._compute_single_cu()
+ # calculate cpu time fraction for container with given flavor
+ cpu_time_percentage = self.single_cu * number_cu
+ # calculate input values for CFS scheduler bandwidth limitation
+ cpu_period, cpu_quota = self._calculate_cpu_cfs_values(
+ cpu_time_percentage)
+ # apply limits to container if changed
+ if d.resources['cpu_period'] != cpu_period or d.resources['cpu_quota'] != cpu_quota:
+ LOG.debug("Setting CPU limit for %r: cpu_quota = cpu_period * limit = %f * %f = %f (op_factor=%f)" % (
+ d.name, cpu_period, cpu_time_percentage, cpu_quota, self.cpu_op_factor))
+ d.updateCpuLimit(cpu_period=int(cpu_period),
+ cpu_quota=int(cpu_quota))
+
+ def _compute_single_cu(self):
+ """
+ Calculate percentage of CPU time of a singe CU unit.
+ :return:
+ """
+ # get cpu time fraction for entire emulation
+ e_cpu = self.registrar.e_cpu
+ # calculate
+ return float(
+ e_cpu) / sum([rm.dc_max_cu for rm in list(self.registrar.resource_models)])
+
+ def _calculate_cpu_cfs_values(self, cpu_time_percentage):
+ """
+ Calculate cpu period and quota for CFS
+ :param cpu_time_percentage: percentage of overall CPU to be used
+ :return: cpu_period, cpu_quota
+ """
+ # (see: https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt)
+ # Attention minimum cpu_quota is 1ms (micro)
+ cpu_period = CPU_PERIOD # lets consider a fixed period of 1000000 microseconds for now
+ # calculate the fraction of cpu time for this container
+ cpu_quota = cpu_period * cpu_time_percentage
+ # ATTENTION >= 1000 to avoid a invalid argument system error ... no
+ # idea why
+ if cpu_quota < 1000:
+ cpu_quota = 1000
+ LOG.warning("Increased CPU quota to avoid system error.")
+ return cpu_period, cpu_quota
+
+ def _apply_mem_limits(self, d):
+ """
+ Calculate real mem limit and apply.
+ :param d: container
+ :return:
+ """
+ number_mu = self._get_flavor(d).get("memory")
+ # get memory amount for entire emulation
+ e_mem = self.registrar.e_mem
+ # calculate amount of memory for a single mu
+ self.single_mu = float(
+ e_mem) / sum([rm.dc_max_mu for rm in list(self.registrar.resource_models)])
+ # calculate mem for given flavor
+ mem_limit = self.single_mu * number_mu
+ mem_limit = self._calculate_mem_limit_value(mem_limit)
+ # apply to container if changed
+ if d.resources['mem_limit'] != mem_limit:
+ LOG.debug("Setting MEM limit for %r: mem_limit = %f MB (op_factor=%f)" %
+ (d.name, mem_limit / 1024 / 1024, self.mem_op_factor))
+ d.updateMemoryLimit(mem_limit=mem_limit)
+
+ def _calculate_mem_limit_value(self, mem_limit):
+ """
+ Calculate actual mem limit as input for cgroup API
+ :param mem_limit: abstract mem limit
+ :return: concrete mem limit
+ """
+ # ATTENTION minimum mem_limit per container is 4MB
+ if mem_limit < 4:
+ mem_limit = 4
+ LOG.warning("Increased MEM limit because it was less than 4.0 MB.")
+ # to byte!
+ return int(mem_limit * 1024 * 1024)