To alter our behavior depending on whether the kernel used supports
certain cgroup parameters or not, this patch adds a helper function
capable of checking that. The function is heavily based on earlier
functions for reading cgroup parameter values, with some refactoring
to keep the code in a readable state.
Signed-off-by: Hrvoje Ribicic <r...@google.com>
---
lib/hypervisor/hv_lxc.py | 52 +++++++++++++++++++---------
test/py/ganeti.hypervisor.hv_lxc_unittest.py | 34 +++++++++++++-----
2 files changed, 61 insertions(+), 25 deletions(-)
diff --git a/lib/hypervisor/hv_lxc.py b/lib/hypervisor/hv_lxc.py
index aa3072f..5ee0e04 100644
--- a/lib/hypervisor/hv_lxc.py
+++ b/lib/hypervisor/hv_lxc.py
@@ -336,37 +336,36 @@ class LXCHypervisor(hv_base.BaseHypervisor):
return cgroups
@classmethod
- def _GetCgroupInstanceSubsysDir(cls, instance_name, subsystem):
- """Return the directory of the cgroup subsystem for the instance.
+ def _GetCgroupSubsysDir(cls, subsystem):
+ """Return the directory of the cgroup subsystem we use.
- @type instance_name: string
- @param instance_name: instance name
@type subsystem: string
@param subsystem: cgroup subsystem name
- @rtype string
- @return path of the instance hierarchy directory for the subsystem
+ @rtype: string
+ @return: path of the hierarchy directory for the subsystem
"""
subsys_dir = cls._GetOrPrepareCgroupSubsysMountPoint(subsystem)
base_group = cls._GetCurrentCgroupSubsysGroups().get(subsystem, "")
- return utils.PathJoin(subsys_dir, base_group, "lxc", instance_name)
+ return utils.PathJoin(subsys_dir, base_group, "lxc")
@classmethod
- def _GetCgroupInstanceParamPath(cls, instance_name, param_name):
+ def _GetCgroupParamPath(cls, param_name, instance_name=None):
"""Return the path of the specified cgroup parameter file.
- @type instance_name: string
- @param instance_name: instance name
@type param_name: string
@param param_name: cgroup subsystem parameter name
- @rtype string
- @return path of the cgroup subsystem parameter file
+ @rtype: string
+ @return: path of the cgroup subsystem parameter file
"""
subsystem = param_name.split(".", 1)[0]
- subsys_dir = cls._GetCgroupInstanceSubsysDir(instance_name, subsystem)
- return utils.PathJoin(subsys_dir, param_name)
+ subsys_dir = cls._GetCgroupSubsysDir(subsystem)
+ if instance_name is not None:
+ return utils.PathJoin(subsys_dir, instance_name, param_name)
+ else:
+ return utils.PathJoin(subsys_dir, param_name)
@classmethod
def _GetCgroupInstanceValue(cls, instance_name, param_name):
@@ -380,7 +379,8 @@ class LXCHypervisor(hv_base.BaseHypervisor):
@return value read from cgroup subsystem fs
"""
- param_path = cls._GetCgroupInstanceParamPath(instance_name, param_name)
+ param_path = cls._GetCgroupParamPath(param_name,
+ instance_name=instance_name)
return utils.ReadFile(param_path).rstrip("\n")
@classmethod
@@ -395,7 +395,8 @@ class LXCHypervisor(hv_base.BaseHypervisor):
@param param_value: cgroup subsystem parameter value to be set
"""
- param_path = cls._GetCgroupInstanceParamPath(instance_name, param_name)
+ param_path = cls._GetCgroupParamPath(param_name,
+ instance_name=instance_name)
# When interacting with cgroup fs, errno is quite important information
# to see what happened when setting a cgroup parameter, so just throw
# an error to the upper level.
@@ -411,6 +412,25 @@ class LXCHypervisor(hv_base.BaseHypervisor):
os.close(fd)
@classmethod
+ def _IsCgroupParameterPresent(cls, parameter, hvparams=None):
+ """Return whether a cgroup parameter can be used.
+
+ This is checked by seeing whether there is a file representation of the
+ parameter in the location where the cgroup is mounted.
+
+ @type parameter: string
+ @param parameter: The name of the parameter.
+ @param hvparams: dict
+ @param hvparams: The hypervisor parameters, optional.
+ @rtype: boolean
+
+ """
+ cls._EnsureCgroupMounts(hvparams)
+ param_path = cls._GetCgroupParamPath(parameter)
+
+ return os.path.exists(param_path)
+
+ @classmethod
def _GetCgroupCpuList(cls, instance_name):
"""Return the list of CPU ids for an instance.
diff --git a/test/py/ganeti.hypervisor.hv_lxc_unittest.py
b/test/py/ganeti.hypervisor.hv_lxc_unittest.py
index 208ddcf..a403d48 100755
--- a/test/py/ganeti.hypervisor.hv_lxc_unittest.py
+++ b/test/py/ganeti.hypervisor.hv_lxc_unittest.py
@@ -178,23 +178,39 @@ class TestCgroupReadData(LXCHypervisorTestCase):
@patch_object(LXCHypervisor, "_GetOrPrepareCgroupSubsysMountPoint")
@patch_object(LXCHypervisor, "_GetCurrentCgroupSubsysGroups")
- def testGetCgroupInstanceSubsysDir(self, getcgg_mock, getmp_mock):
+ def testGetCgroupSubsysDir(self, getcgg_mock, getmp_mock):
getmp_mock.return_value = "/cg"
getcgg_mock.return_value = {"cpuset": "grp"}
- self.assertEqual(self.hv._GetCgroupInstanceSubsysDir("instance1",
"memory"),
- "/cg/lxc/instance1")
- self.assertEqual(self.hv._GetCgroupInstanceSubsysDir("instance1",
"cpuset"),
- "/cg/grp/lxc/instance1")
+ self.assertEqual(
+ self.hv._GetCgroupSubsysDir("memory"), "/cg/lxc"
+ )
+ self.assertEqual(
+ self.hv._GetCgroupSubsysDir("cpuset"), "/cg/grp/lxc"
+ )
- @patch_object(LXCHypervisor, "_GetCgroupInstanceSubsysDir")
+ @patch_object(LXCHypervisor, "_GetOrPrepareCgroupSubsysMountPoint")
+ @patch_object(LXCHypervisor, "_GetCurrentCgroupSubsysGroups")
+ def testGetCgroupParamPath(self, getcgg_mock, getmp_mock):
+ getmp_mock.return_value = "/cg"
+ getcgg_mock.return_value = {"cpuset": "grp"}
+ self.assertEqual(
+ self.hv._GetCgroupParamPath("memory.memsw.limit_in_bytes",
+ instance_name="instance1"),
+ "/cg/lxc/instance1/memory.memsw.limit_in_bytes"
+ )
+ self.assertEqual(
+ self.hv._GetCgroupParamPath("cpuset.cpus"),
+ "/cg/grp/lxc/cpuset.cpus"
+ )
+
+ @patch_object(LXCHypervisor, "_GetCgroupSubsysDir")
def testGetCgroupInstanceValue(self, getdir_mock):
- getdir_mock.return_value = utils.PathJoin(self.cgroot, "memory", "lxc",
- "instance1")
+ getdir_mock.return_value = utils.PathJoin(self.cgroot, "memory", "lxc")
self.assertEqual(self.hv._GetCgroupInstanceValue("instance1",
"memory.limit_in_bytes"),
"128")
getdir_mock.return_value = utils.PathJoin(self.cgroot, "cpuset",
- "some_group", "lxc", "instance1")
+ "some_group", "lxc")
self.assertEqual(self.hv._GetCgroupInstanceValue("instance1",
"cpuset.cpus"),
"0-1")
--
2.2.0.rc0.207.ga3a616c
