[2297] use size of free list for free memory on openbsd, too.

src/lib/python/isc/sysinfo/sysinfo.py

@@ -354,11 +354,11 @@ class SysInfoOpenBSD(SysInfoBSD):
             pass
 
         try:
+            # We use the size of free-list from the vmstat result.
             s = subprocess.check_output(['vmstat'])
             lines = s.decode('utf-8').split('\n')
             v = re.split('\s+', lines[2])
-            used = int(v[4]) * 1024
-            self._mem_free = self._mem_total - used
+            self._mem_free = int(v[5]) * 1024
         except (subprocess.CalledProcessError, OSError):
             pass
 

src/lib/python/isc/sysinfo/tests/sysinfo_test.py

@@ -379,7 +379,7 @@ class SysInfoTest(unittest.TestCase):
         self.assertEqual((0.7, 0.9, 0.8), s.get_loadavg())
         self.assertFalse(s.get_platform_is_smp())
         self.assertEqual(543214321, s.get_mem_total())
-        self.assertEqual(543214321 - (121212 * 1024), s.get_mem_free())
+        self.assertEqual(123456 * 1024, s.get_mem_free())
         self.assertEqual(566791168, s.get_mem_swap_total())
         self.assertEqual(566789120, s.get_mem_swap_free())