scripts/kvm/kvm_stat: Encapsulate filters variable

The variable was only used in one class but still was defined
globally. Additionaly the detect_platform routine which prepares the
data that goes into the variable was called on each start of the
script, no matter if the class was needed.

To make the variable local to the TracepointProvider class, a new
function that calls detect_platform and returns the filters was
introduced.

Signed-off-by: Janosch Frank <frankja@linux.vnet.ibm.com>
Message-Id: <1452525484-32309-22-git-send-email-frankja@linux.vnet.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/scripts/kvm/kvm_stat b/scripts/kvm/kvm_stat
index 083dd2f6a33533a2c65add84bb9ce5c4d1e38954..7837f40ea644cde008bf16ede9ba05e0df11a355 100755 (executable)
--- a/scripts/kvm/kvm_stat
+++ b/scripts/kvm/kvm_stat
@@ -302,10 +302,14 @@ def get_online_cpus():
         cpu_string = cpu_list.readline()
         return parse_int_list(cpu_string)
 
-filters = {}
-filters['kvm_userspace_exit'] = ('reason', USERSPACE_EXIT_REASONS)
-if EXIT_REASONS:
-    filters['kvm_exit'] = ('exit_reason', EXIT_REASONS)
+
+def get_filters():
+    detect_platform()
+    filters = {}
+    filters['kvm_userspace_exit'] = ('reason', USERSPACE_EXIT_REASONS)
+    if EXIT_REASONS:
+        filters['kvm_exit'] = ('exit_reason', EXIT_REASONS)
+    return filters
 
 libc = ctypes.CDLL('libc.so.6', use_errno=True)
 syscall = libc.syscall
@@ -385,6 +389,7 @@ class Event(object):
 class TracepointProvider(object):
     def __init__(self):
         self.group_leaders = []
+        self.filters = get_filters()
         self._fields = self.get_available_fields()
         self.setup_traces()
         self.fields = self._fields
@@ -394,8 +399,8 @@ class TracepointProvider(object):
         fields = walkdir(path)[1]
         extra = []
         for field in fields:
-            if field in filters:
-                filter_name_, filter_dicts = filters[field]
+            if field in self.filters:
+                filter_name_, filter_dicts = self.filters[field]
                 for name in filter_dicts:
                     extra.append(field + '(' + name + ')')
         fields += extra
@@ -420,8 +425,9 @@ class TracepointProvider(object):
                 match = re.match(r'(.*)\((.*)\)', name)
                 if match:
                     tracepoint, sub = match.groups()
-                    tracefilter = '%s==%d\0' % (filters[tracepoint][0],
-                                                filters[tracepoint][1][sub])
+                    tracefilter = ('%s==%d\0' %
+                                   (self.filters[tracepoint][0],
+                                    self.filters[tracepoint][1][sub]))
                 group.add_event(name, event_set='kvm',
                                 tracepoint=tracepoint,
                                 tracefilter=tracefilter)
@@ -652,7 +658,6 @@ def check_access():
 
 def main():
     check_access()
-    detect_platform()
     options = get_options()
     providers = get_providers(options)
     stats = Stats(providers, fields=options.fields)