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OpenStack Study: pci_manager.py**** CubicPower OpenStack Study ****
# Copyright (c) 2013 Intel, Inc. # Copyright (c) 2013 OpenStack Foundation # All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. import collections from nova.compute import task_states from nova.compute import vm_states from nova import context from nova import exception from nova.objects import instance from nova.objects import pci_device from nova.openstack.common.gettextutils import _ from nova.openstack.common import log as logging from nova.pci import pci_request from nova.pci import pci_stats from nova.pci import pci_utils LOG = logging.getLogger(__name__)
**** CubicPower OpenStack Study **** class PciDevTracker(object): """Manage pci devices in a compute node. This class fetches pci passthrough information from hypervisor and trackes the usage of these devices. It's called by compute node resource tracker to allocate and free devices to/from instances, and to update the available pci passthrough devices information from hypervisor periodically. The devices information is updated to DB when devices information is changed. """
**** CubicPower OpenStack Study **** def __init__(self, node_id=None): """Create a pci device tracker. If a node_id is passed in, it will fetch pci devices information from database, otherwise, it will create an empty devices list and the resource tracker will update the node_id information later. """ super(PciDevTracker, self).__init__() self.stale = {} self.node_id = node_id self.stats = pci_stats.PciDeviceStats() if node_id: self.pci_devs = pci_device.PciDeviceList.get_by_compute_node( context, node_id) else: self.pci_devs = pci_device.PciDeviceList() self._initial_instance_usage()
**** CubicPower OpenStack Study **** def _initial_instance_usage(self): self.allocations = collections.defaultdict(list) self.claims = collections.defaultdict(list) for dev in self.pci_devs: uuid = dev['instance_uuid'] if dev['status'] == 'claimed': self.claims[uuid].append(dev) elif dev['status'] == 'allocated': self.allocations[uuid].append(dev) elif dev['status'] == 'available': self.stats.add_device(dev)
**** CubicPower OpenStack Study **** def _filter_devices_for_spec(self, request_spec, pci_devs): return [p for p in pci_devs if pci_utils.pci_device_prop_match(p, request_spec)]
**** CubicPower OpenStack Study **** def _get_free_devices_for_request(self, pci_request, pci_devs): count = pci_request.get('count', 1) spec = pci_request.get('spec', []) devs = self._filter_devices_for_spec(spec, pci_devs) if len(devs) < count: return None else: return devs[:count] @property
**** CubicPower OpenStack Study **** def free_devs(self): return [dev for dev in self.pci_devs if dev.status == 'available']
**** CubicPower OpenStack Study **** def get_free_devices_for_requests(self, pci_requests): """Select free pci devices for requests Pci_requests is a list of pci_request dictionaries. Each dictionary has three keys: count: number of pci devices required, default 1 spec: the pci properties that the devices should meet alias_name: alias the pci_request is translated from, optional If any single pci_request cannot find any free devices, then the entire request list will fail. """ alloc = [] for request in pci_requests: available = self._get_free_devices_for_request( request, [p for p in self.free_devs if p not in alloc]) if not available: return [] alloc.extend(available) return alloc @property
**** CubicPower OpenStack Study **** def all_devs(self): return self.pci_devs
**** CubicPower OpenStack Study **** def save(self, context): for dev in self.pci_devs: if dev.obj_what_changed(): dev.save(context) self.pci_devs.objects = [dev for dev in self.pci_devs if dev['status'] != 'deleted'] @property
**** CubicPower OpenStack Study **** def pci_stats(self): return self.stats
**** CubicPower OpenStack Study **** def set_hvdevs(self, devices): """Sync the pci device tracker with hypervisor information. To support pci device hot plug, we sync with the hypervisor periodically, fetching all devices information from hypervisor, update the tracker and sync the DB information. Devices should not be hot-plugged when assigned to a guest, but possibly the hypervisor has no such guarantee. The best we can do is to give a warning if a device is changed or removed while assigned. """ exist_addrs = set([dev['address'] for dev in self.pci_devs]) new_addrs = set([dev['address'] for dev in devices]) for existed in self.pci_devs: if existed['address'] in exist_addrs - new_addrs: try: existed.remove() except exception.PciDeviceInvalidStatus as e: LOG.warn(_("Trying to remove device with %(status)s " "ownership %(instance_uuid)s because of " "%(pci_exception)s"), {'status': existed.status, 'instance_uuid': existed.instance_uuid, 'pci_exception': e.format_message()}) # Note(yjiang5): remove the device by force so that # db entry is cleaned in next sync. existed.status = 'removed' else: # Note(yjiang5): no need to update stats if an assigned # device is hot removed. self.stats.consume_device(existed) else: new_value = next((dev for dev in devices if dev['address'] == existed['address'])) new_value['compute_node_id'] = self.node_id if existed['status'] in ('claimed', 'allocated'): # Pci properties may change while assigned because of # hotplug or config changes. Although normally this should # not happen. # As the devices have been assigned to a instance, we defer # the change till the instance is destroyed. We will # not sync the new properties with database before that. # TODO(yjiang5): Not sure if this is a right policy, but # at least it avoids some confusion and, if needed, # we can add more action like killing the instance # by force in future. self.stale[dev['address']] = dev else: existed.update_device(new_value) for dev in [dev for dev in devices if dev['address'] in new_addrs - exist_addrs]: dev['compute_node_id'] = self.node_id dev_obj = pci_device.PciDevice.create(dev) self.pci_devs.objects.append(dev_obj) self.stats.add_device(dev_obj)
**** CubicPower OpenStack Study **** def _claim_instance(self, instance, prefix=''): pci_requests = pci_request.get_instance_pci_requests( instance, prefix) if not pci_requests: return None devs = self.get_free_devices_for_requests(pci_requests) if not devs: raise exception.PciDeviceRequestFailed(pci_requests) for dev in devs: dev.claim(instance) self.stats.consume_device(dev) return devs
**** CubicPower OpenStack Study **** def _allocate_instance(self, instance, devs): for dev in devs: dev.allocate(instance)
**** CubicPower OpenStack Study **** def _free_device(self, dev, instance=None): dev.free(instance) stale = self.stale.pop(dev['address'], None) if stale: dev.update_device(stale) self.stats.add_device(dev)
**** CubicPower OpenStack Study **** def _free_instance(self, instance): # Note(yjiang5): When a instance is resized, the devices in the # destination node are claimed to the instance in prep_resize stage. # However, the instance contains only allocated devices # information, not the claimed one. So we can't use # instance['pci_devices'] to check the devices to be freed. for dev in self.pci_devs: if (dev['status'] in ('claimed', 'allocated') and dev['instance_uuid'] == instance['uuid']): self._free_device(dev)
**** CubicPower OpenStack Study **** def update_pci_for_instance(self, instance): """Update instance's pci usage information. The caller should hold the COMPUTE_RESOURCE_SEMAPHORE lock """ uuid = instance['uuid'] vm_state = instance['vm_state'] task_state = instance['task_state'] if vm_state == vm_states.DELETED: if self.allocations.pop(uuid, None): self._free_instance(instance) elif self.claims.pop(uuid, None): self._free_instance(instance) elif task_state == task_states.RESIZE_MIGRATED: devs = self.allocations.pop(uuid, None) if devs: self._free_instance(instance) elif task_state == task_states.RESIZE_FINISH: devs = self.claims.pop(uuid, None) if devs: self._allocate_instance(instance, devs) self.allocations[uuid] = devs elif (uuid not in self.allocations and uuid not in self.claims): devs = self._claim_instance(instance) if devs: self._allocate_instance(instance, devs) self.allocations[uuid] = devs
**** CubicPower OpenStack Study **** def update_pci_for_migration(self, instance, sign=1): """Update instance's pci usage information when it is migrated. The caller should hold the COMPUTE_RESOURCE_SEMAPHORE lock. :param sign: claim devices for instance when sign is 1, remove the claims when sign is -1 """ uuid = instance['uuid'] if sign == 1 and uuid not in self.claims: devs = self._claim_instance(instance, 'new_') if devs: self.claims[uuid] = devs if sign == -1 and uuid in self.claims: self._free_instance(instance)
**** CubicPower OpenStack Study **** def clean_usage(self, instances, migrations, orphans): """Remove all usages for instances not passed in the parameter. The caller should hold the COMPUTE_RESOURCE_SEMAPHORE lock """ existed = [inst['uuid'] for inst in instances] existed += [mig['instance_uuid'] for mig in migrations] existed += [inst['uuid'] for inst in orphans] for uuid in self.claims.keys(): if uuid not in existed: devs = self.claims.pop(uuid, []) for dev in devs: self._free_device(dev) for uuid in self.allocations.keys(): if uuid not in existed: devs = self.allocations.pop(uuid, []) for dev in devs: self._free_device(dev)
**** CubicPower OpenStack Study **** def set_compute_node_id(self, node_id): """Set the compute node id that this object is tracking for. In current resource tracker implementation, the compute_node entry is created in the last step of update_available_resoruces, thus we have to lazily set the compute_node_id at that time. """ if self.node_id and self.node_id != node_id: raise exception.PciTrackerInvalidNodeId(node_id=self.node_id, new_node_id=node_id) self.node_id = node_id for dev in self.pci_devs: dev.compute_node_id = node_id def get_instance_pci_devs(inst): """Get the devices assigned to the instances.""" if isinstance(inst, instance.Instance): return inst.pci_devices else: ctxt = context.get_admin_context() return pci_device.PciDeviceList.get_by_instance_uuid( ctxt, inst['uuid'])
**** CubicPower OpenStack Study **** def get_instance_pci_devs(inst): """Get the devices assigned to the instances.""" if isinstance(inst, instance.Instance): return inst.pci_devices else: ctxt = context.get_admin_context() return pci_device.PciDeviceList.get_by_instance_uuid( ctxt, inst['uuid'])
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