Added method to get NUMA nodes with memory

This patch adds method to get list of nodes with memory on given
machine.
Signed-off-by: NHarish <harish@linux.vnet.ibm.com>

avocado/utils/memory.py

@@ -26,6 +26,7 @@ import logging
 from . import process
 from . import genio
 from . import wait
+from . import data_structures
 from .data_structures import DataSize
 
 
@@ -216,6 +217,22 @@ def numa_nodes():
     return (sorted(nodes))
 
 
+def numa_nodes_with_memory():
+    """
+    Get a list of NUMA nodes present with memory on the system.
+
+    :return: List with nodes which has memory.
+    """
+    mem_path = '/sys/devices/system/node/has_normal_memory'
+    if not os.path.exists(mem_path):
+        mem_path = '/sys/devices/system/node/has_memory'
+        if not os.path.exists(mem_path):
+            raise MemError("No NUMA nodes have memory")
+
+    node_list = str(genio.read_file(mem_path).rstrip('\n'))
+    return data_structures.comma_separated_ranges_to_list(node_list)
+
+
 def node_size():
     """
     Return node size.

selftests/unit/test_utils_memory.py

+import unittest
+
+try:
+    from unittest import mock
+except ImportError:
+    import mock
+
+from avocado.utils import memory
+
+
+class UtilsMemoryTest(unittest.TestCase):
+
+    def test_numa_nodes_with_memory(self):
+        file_values = [u"0\n", u"1-3", u"0-1,12-14\n"]
+        expected_values = [[0], [1, 2, 3], [0, 1, 12, 13, 14]]
+        for value, exp in zip(file_values, expected_values):
+            with mock.patch('os.path.exists', return_value=True):
+                with mock.patch('avocado.utils.genio.read_file', return_value=value):
+                    self.assertEqual(
+                        memory.numa_nodes_with_memory(), exp)
+
+
+if __name__ == '__main__':
+    unittest.main()