[sysprof] governor: always disable paranoid status

[Christian Hergert <chergert src gnome org>]

commit 86fb061899c4bb85313927f4d717c8b2ede4252c
Author: Christian Hergert <chergert redhat com>
Date:   Wed Feb 24 12:19:36 2021 -0800

    governor: always disable paranoid status
    
    This allows us to always attempt to disable the perf_event_paranoid
    setting to -1 while we profile.

 src/libsysprof/sysprof-governor-source.c | 102 +++++++++++++++----------------
 1 file changed, 49 insertions(+), 53 deletions(-)
---
diff --git a/src/libsysprof/sysprof-governor-source.c b/src/libsysprof/sysprof-governor-source.c
index 794d1bf..7c2f67a 100644
--- a/src/libsysprof/sysprof-governor-source.c
+++ b/src/libsysprof/sysprof-governor-source.c
@@ -117,6 +117,7 @@ static void
 sysprof_governor_source_init (SysprofGovernorSource *self)
 {
   self->disable_governor = FALSE;
+  self->old_paranoid = 2;
 }
 
 SysprofSource *
@@ -178,73 +179,69 @@ sysprof_governor_source_deserialize (SysprofSource *source,
 }
 
 static void
-disable_paranoid_cb (GObject      *object,
+disable_governor_cb (GObject      *object,
                      GAsyncResult *result,
                      gpointer      user_data)
 {
   SysprofHelpers *helpers = (SysprofHelpers *)object;
   g_autoptr(SysprofGovernorSource) self = user_data;
   g_autoptr(GError) error = NULL;
-  int old_paranoid;
+  g_autofree gchar *old_governor = NULL;
 
   g_assert (SYSPROF_IS_HELPERS (helpers));
   g_assert (G_IS_ASYNC_RESULT (result));
   g_assert (SYSPROF_IS_GOVERNOR_SOURCE (self));
 
-  if (!sysprof_helpers_set_paranoid_finish (helpers, result, &old_paranoid, &error))
-    g_warning ("Failed to change perf_event_paranoid: %s", error->message);
+  if (!sysprof_helpers_set_governor_finish (helpers, result, &old_governor, &error))
+    g_warning ("Failed to change governor: %s", error->message);
   else
-    self->old_paranoid = old_paranoid;
+    self->old_governor = g_steal_pointer (&old_governor);
 
   sysprof_source_emit_ready (SYSPROF_SOURCE (self));
 }
 
 static void
-disable_governor_cb (GObject      *object,
+disable_paranoid_cb (GObject      *object,
                      GAsyncResult *result,
                      gpointer      user_data)
 {
   SysprofHelpers *helpers = (SysprofHelpers *)object;
   g_autoptr(SysprofGovernorSource) self = user_data;
   g_autoptr(GError) error = NULL;
-  g_autofree gchar *old_governor = NULL;
+  int old_paranoid;
 
   g_assert (SYSPROF_IS_HELPERS (helpers));
   g_assert (G_IS_ASYNC_RESULT (result));
   g_assert (SYSPROF_IS_GOVERNOR_SOURCE (self));
 
-  if (!sysprof_helpers_set_governor_finish (helpers, result, &old_governor, &error))
-    g_warning ("Failed to change governor: %s", error->message);
+  if (!sysprof_helpers_set_paranoid_finish (helpers, result, &old_paranoid, &error))
+    g_warning ("Failed to change perf_event_paranoid: %s", error->message);
   else
-    self->old_governor = g_steal_pointer (&old_governor);
+    self->old_paranoid = old_paranoid;
 
-  /* Now tweak paranoid setting */
-  sysprof_helpers_set_paranoid_async (helpers,
-                                      -1,
-                                      NULL,
-                                      disable_paranoid_cb,
-                                      g_steal_pointer (&self));
+  if (!self->disable_governor)
+    sysprof_source_emit_ready (SYSPROF_SOURCE (self));
+  else
+    sysprof_helpers_set_governor_async (helpers,
+                                        "performance",
+                                        NULL,
+                                        disable_governor_cb,
+                                        g_steal_pointer (&self));
 }
 
-
 static void
-enable_paranoid_cb (GObject      *object,
-                    GAsyncResult *result,
-                    gpointer      user_data)
+sysprof_governor_source_prepare (SysprofSource *source)
 {
-  SysprofHelpers *helpers = (SysprofHelpers *)object;
-  g_autoptr(SysprofGovernorSource) self = user_data;
-  g_autoptr(GError) error = NULL;
-  int old_governor;
+  SysprofGovernorSource *self = (SysprofGovernorSource *)source;
+  SysprofHelpers *helpers = sysprof_helpers_get_default ();
 
-  g_assert (SYSPROF_IS_HELPERS (helpers));
-  g_assert (G_IS_ASYNC_RESULT (result));
   g_assert (SYSPROF_IS_GOVERNOR_SOURCE (self));
 
-  if (!sysprof_helpers_set_paranoid_finish (helpers, result, &old_governor, &error))
-    g_warning ("Failed to change event_perf_paranoid: %s", error->message);
-
-  sysprof_source_emit_finished (SYSPROF_SOURCE (self));
+  sysprof_helpers_set_paranoid_async (helpers,
+                                      -1,
+                                      NULL,
+                                      disable_paranoid_cb,
+                                      g_object_ref (self));
 }
 
 static void
@@ -256,7 +253,6 @@ enable_governor_cb (GObject      *object,
   g_autoptr(SysprofGovernorSource) self = user_data;
   g_autoptr(GError) error = NULL;
   g_autofree gchar *old_governor = NULL;
-  int previous;
 
   g_assert (SYSPROF_IS_HELPERS (helpers));
   g_assert (G_IS_ASYNC_RESULT (result));
@@ -267,31 +263,34 @@ enable_governor_cb (GObject      *object,
 
   g_clear_pointer (&self->old_governor, g_free);
 
-  /* Restore paranoid setting */
-  previous = self->old_paranoid;
-  sysprof_helpers_set_paranoid_async (helpers,
-                                      previous,
-                                      NULL,
-                                      enable_paranoid_cb,
-                                      g_steal_pointer (&self));
+  sysprof_source_emit_finished (SYSPROF_SOURCE (self));
 }
 
 static void
-sysprof_governor_source_prepare (SysprofSource *source)
+enable_paranoid_cb (GObject      *object,
+                    GAsyncResult *result,
+                    gpointer      user_data)
 {
-  SysprofGovernorSource *self = (SysprofGovernorSource *)source;
-  SysprofHelpers *helpers = sysprof_helpers_get_default ();
+  SysprofHelpers *helpers = (SysprofHelpers *)object;
+  g_autoptr(SysprofGovernorSource) self = user_data;
+  g_autoptr(GError) error = NULL;
+  int old_governor;
 
+  g_assert (SYSPROF_IS_HELPERS (helpers));
+  g_assert (G_IS_ASYNC_RESULT (result));
   g_assert (SYSPROF_IS_GOVERNOR_SOURCE (self));
 
+  if (!sysprof_helpers_set_paranoid_finish (helpers, result, &old_governor, &error))
+    g_warning ("Failed to change event_perf_paranoid: %s", error->message);
+
   if (!self->disable_governor)
-    sysprof_source_emit_ready (source);
+    sysprof_source_emit_finished (SYSPROF_SOURCE (self));
   else
     sysprof_helpers_set_governor_async (helpers,
-                                        "performance",
+                                        self->old_governor,
                                         NULL,
-                                        disable_governor_cb,
-                                        g_object_ref (self));
+                                        enable_governor_cb,
+                                        g_steal_pointer (&self));
 }
 
 static void
@@ -302,14 +301,11 @@ sysprof_governor_source_stop (SysprofSource *source)
 
   g_assert (SYSPROF_IS_GOVERNOR_SOURCE (self));
 
-  if (self->old_governor == NULL)
-    sysprof_source_emit_finished (source);
-  else
-    sysprof_helpers_set_governor_async (helpers,
-                                        self->old_governor,
-                                        NULL,
-                                        enable_governor_cb,
-                                        g_object_ref (self));
+  sysprof_helpers_set_paranoid_async (helpers,
+                                      self->old_paranoid,
+                                      NULL,
+                                      enable_paranoid_cb,
+                                      g_object_ref (self));
 }
 
 static void