scripts/kvm/kvm_stat: Cleanup of TracepointProvider

Variables with bad names like f and m were renamed to their full name,
so it is clearer which data they contain.

Unneeded variables were removed and the field generating code was
moved in an own function.

dict.iteritems() was removed as directly iterating over a dictionary
also yields the needed keys.
Signed-off-by: NJanosch Frank <frankja@linux.vnet.ibm.com>
Message-Id: <1452525484-32309-20-git-send-email-frankja@linux.vnet.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

scripts/kvm/kvm_stat

@@ -375,45 +375,47 @@ class Event(object):
 
 class TracepointProvider(object):
     def __init__(self):
+        self.group_leaders = []
+        self._fields = self.get_available_fields()
+        self.setup_traces()
+        self.fields = self._fields
+
+    def get_available_fields(self):
         path = os.path.join(PATH_DEBUGFS_TRACING, 'events', 'kvm')
         fields = walkdir(path)[1]
         extra = []
-        for f in fields:
-            if f in filters:
-                subfield, values = filters[f]
-                for name, number in values.iteritems():
-                    extra.append(f + '(' + name + ')')
+        for field in fields:
+            if field in filters:
+                filter_name_, filter_dicts = filters[field]
+                for name in filter_dicts:
+                    extra.append(field + '(' + name + ')')
         fields += extra
-        self._setup(fields)
-        self.fields = fields
+        return fields
 
-    def _setup(self, _fields):
-        self._fields = _fields
+    def setup_traces(self):
         cpus = get_online_cpus()
 
         # The constant is needed as a buffer for python libs, std
         # streams and other files that the script opens.
-        rlimit = len(cpus) * len(_fields) + 50
+        rlimit = len(cpus) * len(self._fields) + 50
         try:
             resource.setrlimit(resource.RLIMIT_NOFILE, (rlimit, rlimit))
         except ValueError:
             sys.exit("NOFILE rlimit could not be raised to {0}".format(rlimit))
 
-        events = []
-        self.group_leaders = []
         for cpu in cpus:
             group = Group(cpu)
-            for name in _fields:
+            for name in self._fields:
                 tracepoint = name
                 tracefilter = None
-                m = re.match(r'(.*)\((.*)\)', name)
-                if m:
-                    tracepoint, sub = m.groups()
+                match = re.match(r'(.*)\((.*)\)', name)
+                if match:
+                    tracepoint, sub = match.groups()
                     tracefilter = '%s==%d\0' % (filters[tracepoint][0],
                                                 filters[tracepoint][1][sub])
-                event = group.add_event(name, event_set='kvm',
-                                        tracepoint=tracepoint,
-                                        tracefilter=tracefilter)
+                group.add_event(name, event_set='kvm',
+                                tracepoint=tracepoint,
+                                tracefilter=tracefilter)
             self.group_leaders.append(group)
 
     @property