pci: avoid parsing whitelist repeatedly

Prior to this patch, everytime a pci device
was added or removed, get_pci_device_devspec() in
whitelist was called which creates Whitelist object
and parses CONF.pci_passthrough_whitelist.

This patch fixes it by storing the whitelist/device filter
as an attribute of PciDeviceStats class similar to
PciDevTracker.

Change-Id: I0aadd57f7833ac5da42abf557a4602fb1d5db5f8

nova/pci/manager.py

@@ -55,8 +55,8 @@ class PciDevTracker(object):
         super(PciDevTracker, self).__init__()
         self.stale = {}
         self.node_id = node_id
-        self.stats = stats.PciDeviceStats()
         self.dev_filter = whitelist.Whitelist(CONF.pci_passthrough_whitelist)
+        self.stats = stats.PciDeviceStats(dev_filter=self.dev_filter)
         self._context = context
         if node_id:
             self.pci_devs = objects.PciDeviceList.get_by_compute_node(

nova/pci/stats.py

@@ -16,6 +16,7 @@
 
 import copy
 
+from oslo_config import cfg
 from oslo_log import log as logging
 import six
 
@@ -28,6 +29,7 @@ from nova.pci import utils
 from nova.pci import whitelist
 
 
+CONF = cfg.CONF
 LOG = logging.getLogger(__name__)
 
 
@@ -57,12 +59,14 @@ class PciDeviceStats(object):
 
     pool_keys = ['product_id', 'vendor_id', 'numa_node', 'dev_type']
 
-    def __init__(self, stats=None):
+    def __init__(self, stats=None, dev_filter=None):
         super(PciDeviceStats, self).__init__()
         # NOTE(sbauza): Stats are a PCIDevicePoolList object
         self.pools = [pci_pool.to_dict()
                       for pci_pool in stats] if stats else []
         self.pools.sort(key=lambda item: len(item))
+        self.dev_filter = dev_filter or whitelist.Whitelist(
+            CONF.pci_passthrough_whitelist)
 
     def _equal_properties(self, dev, entry, matching_keys):
         return all(dev.get(prop) == entry.get(prop)
@@ -86,7 +90,7 @@ class PciDeviceStats(object):
         """
         # Don't add a device that doesn't have a matching device spec.
         # This can happen during initial sync up with the controller
-        devspec = whitelist.get_pci_device_devspec(dev)
+        devspec = self.dev_filter.get_devspec(dev)
         if not devspec:
             return
         tags = devspec.get_tags()

nova/tests/unit/pci/fakes.py

@@ -23,7 +23,7 @@ from nova.pci import whitelist
 def fake_pci_whitelist():
     devspec = mock.Mock()
     devspec.get_tags.return_value = None
-    patcher = mock.patch.object(whitelist, 'get_pci_device_devspec',
+    patcher = mock.patch.object(whitelist.Whitelist, 'get_devspec',
                      return_value=devspec)
     patcher.start()
     return patcher

nova/tests/unit/pci/test_stats.py

@@ -16,12 +16,17 @@
 import mock
 import six
 
+from oslo_config import cfg
+
 from nova import exception
 from nova import objects
 from nova.objects import fields
 from nova.pci import stats
+from nova.pci import whitelist
 from nova import test
 from nova.tests.unit.pci import fakes
+
+CONF = cfg.CONF
 fake_pci_1 = {
     'compute_node_id': 1,
     'address': '0000:00:00.1',
@@ -202,6 +207,16 @@ class PciDeviceStatsTestCase(test.NoDBTestCase):
         self.assertEqual(set(['v3']),
                          set([dev.vendor_id for dev in devs]))
 
+    @mock.patch(
+        'nova.pci.whitelist.Whitelist._parse_white_list_from_config')
+    def test_white_list_parsing(self, mock_whitelist_parse):
+        white_list = '{"product_id":"0001", "vendor_id":"8086"}'
+        CONF.set_override('pci_passthrough_whitelist', white_list)
+        pci_stats = stats.PciDeviceStats()
+        pci_stats.add_device(self.fake_dev_2)
+        pci_stats.remove_device(self.fake_dev_2)
+        self.assertEqual(1, mock_whitelist_parse.call_count)
+
 
 class PciDeviceStatsWithTagsTestCase(test.NoDBTestCase):
 
@@ -211,7 +226,8 @@ class PciDeviceStatsWithTagsTestCase(test.NoDBTestCase):
                         '"address":"*:0a:00.*","physical_network":"physnet1"}',
                        '{"vendor_id":"1137","product_id":"0072"}']
         self.flags(pci_passthrough_whitelist=white_list)
-        self.pci_stats = stats.PciDeviceStats()
+        dev_filter = whitelist.Whitelist(white_list)
+        self.pci_stats = stats.PciDeviceStats(dev_filter=dev_filter)
 
     def _create_pci_devices(self):
         self.pci_tagged_devices = []