Fix: Reading huge pages information during Qemu start

Reading information from sysfs or proc files is randomly failing
returning empty string without any error.
This fix suppose to add the retries to read the hugepages
information multiple times and raise exception if reading failed.

Change-Id: I7c88504765c39b11c81f7a8e77e5b0e32b7225fe
Signed-off-by: pmikus <pmikus@cisco.com>

1 files changed, 82 insertions, 13 deletions

diff --git a/resources/libraries/python/QemuUtils.py b/resources/libraries/python/QemuUtils.py
index cfdbc7ffa4..ea1d56a3c0 100644
--- a/resources/libraries/python/QemuUtils.py
+++ b/resources/libraries/python/QemuUtils.py
@@ -15,7 +15,6 @@
 
 from time import time, sleep
 import json
-import re
 
 from robot.api import logger
 
@@ -252,7 +251,8 @@ class QemuUtils(object):
         if int(ret_code) != 0:
             logger.debug('QGA execute failed {0}'.format(stderr))
             raise RuntimeError('QGA execute "{0}" '
-                               'failed on {1}'.format(cmd, self._node['host']))
+                               'failed on {1}'.format(qga_cmd,
+                                                      self._node['host']))
         logger.trace(stdout)
         if not stdout:
             return {}
@@ -337,17 +337,12 @@ class QemuUtils(object):
         """Huge page check."""
         huge_mnt = self._qemu_opt.get('huge_mnt')
         mem_size = self._qemu_opt.get('mem_size')
-        # Check size of free huge pages
-        (_, output, _) = self._ssh.exec_command('grep Huge /proc/meminfo')
-        regex = re.compile(r'HugePages_Free:\s+(\d+)')
-        match = regex.search(output)
-        huge_free = int(match.group(1))
-        regex = re.compile(r'HugePages_Total:\s+(\d+)')
-        match = regex.search(output)
-        huge_total = int(match.group(1))
-        regex = re.compile(r'Hugepagesize:\s+(\d+)')
-        match = regex.search(output)
-        huge_size = int(match.group(1))
+
+        # Get huge pages information
+        huge_size = self._get_huge_page_size()
+        huge_free = self._get_huge_page_free(huge_size)
+        huge_total = self._get_huge_page_total(huge_size)
+
         # Check if memory reqested by qemu is available on host
         if (mem_size * 1024) > (huge_free * huge_size):
             # If we want to allocate hugepage dynamically
@@ -399,6 +394,80 @@ class QemuUtils(object):
                 raise RuntimeError('Mount huge pages failed on {0}'.format(
                     self._node['host']))
 
+    def _get_huge_page_size(self):
+        """Get default size of huge pages in system.
+
+        :returns: Default size of free huge pages in system.
+        :rtype: int
+        :raises: RuntimeError if reading failed for three times.
+        """
+        # TODO: remove to dedicated library
+        cmd_huge_size = "grep Hugepagesize /proc/meminfo | awk '{ print $2 }'"
+        for _ in range(3):
+            (ret, out, _) = self._ssh.exec_command_sudo(cmd_huge_size)
+            if ret == 0:
+                try:
+                    huge_size = int(out)
+                except ValueError:
+                    logger.trace('Reading huge page size information failed')
+                else:
+                    break
+        else:
+            raise RuntimeError('Getting huge page size information failed.')
+        return huge_size
+
+    def _get_huge_page_free(self, huge_size):
+        """Get total number of huge pages in system.
+
+        :param huge_size: Size of hugepages.
+        :type huge_size: int
+        :returns: Number of free huge pages in system.
+        :rtype: int
+        :raises: RuntimeError if reading failed for three times.
+        """
+        # TODO: add numa aware option
+        # TODO: remove to dedicated library
+        cmd_huge_free = 'cat /sys/kernel/mm/hugepages/hugepages-{0}kB/'\
+            'free_hugepages'.format(huge_size)
+        for _ in range(3):
+            (ret, out, _) = self._ssh.exec_command_sudo(cmd_huge_free)
+            if ret == 0:
+                try:
+                    huge_free = int(out)
+                except ValueError:
+                    logger.trace('Reading free huge pages information failed')
+                else:
+                    break
+        else:
+            raise RuntimeError('Getting free huge pages information failed.')
+        return huge_free
+
+    def _get_huge_page_total(self, huge_size):
+        """Get total number of huge pages in system.
+
+        :param huge_size: Size of hugepages.
+        :type huge_size: int
+        :returns: Total number of huge pages in system.
+        :rtype: int
+        :raises: RuntimeError if reading failed for three times.
+        """
+        # TODO: add numa aware option
+        # TODO: remove to dedicated library
+        cmd_huge_total = 'cat /sys/kernel/mm/hugepages/hugepages-{0}kB/'\
+            'nr_hugepages'.format(huge_size)
+        for _ in range(3):
+            (ret, out, _) = self._ssh.exec_command_sudo(cmd_huge_total)
+            if ret == 0:
+                try:
+                    huge_total = int(out)
+                except ValueError:
+                    logger.trace('Reading total huge pages information failed')
+                else:
+                    break
+        else:
+            raise RuntimeError('Getting total huge pages information failed.')
+        return huge_total
+
     def qemu_start(self):
         """Start QEMU and wait until VM boot.