libnm: pre-allocate buffer in _nm_sett_info_property_override_create_array()

The buffer created here is only temporary to construct the property info
by _nm_setting_class_commit_full(). We can afford to allocate more than
necessary, if we thereby avoid several reallocations.

2 files changed, 27 insertions, 15 deletions

diff --git a/src/libnm-core-impl/nm-setting-private.h b/src/libnm-core-impl/nm-setting-private.h
index e8373f8e63..7d237dc4c7 100644
--- a/src/libnm-core-impl/nm-setting-private.h
+++ b/src/libnm-core-impl/nm-setting-private.h
@@ -279,9 +279,18 @@ gboolean _nm_setting_property_is_regular_secret_flags(NMSetting * setting,
 /*****************************************************************************/
 
 static inline GArray *
+_nm_sett_info_property_override_create_array_sized(guint reserved_size)
+{
+    return g_array_sized_new(FALSE, FALSE, sizeof(NMSettInfoProperty), reserved_size);
+}
+
+static inline GArray *
 _nm_sett_info_property_override_create_array(void)
 {
-    return g_array_new(FALSE, FALSE, sizeof(NMSettInfoProperty));
+    /* pre-allocate a relatively large buffer to avoid frequent re-allocations.
+     * Note that the buffer is only short-lived and will be destroyed by
+     * _nm_setting_class_commit_full(). */
+    return _nm_sett_info_property_override_create_array_sized(20);
 }
 
 GArray *_nm_sett_info_property_override_create_array_ip_config(void);
diff --git a/src/libnm-core-impl/nm-setting.c b/src/libnm-core-impl/nm-setting.c
index 2e373a5ab0..ec4557cc60 100644
--- a/src/libnm-core-impl/nm-setting.c
+++ b/src/libnm-core-impl/nm-setting.c
@@ -296,7 +296,9 @@ _nm_setting_class_commit_full(NMSettingClass *            setting_class,
 {
     NMSettInfoSetting *sett_info;
     gs_free GParamSpec **property_specs = NULL;
-    guint                i, n_property_specs, override_len;
+    guint                n_property_specs;
+    guint                override_len;
+    guint                i;
 
     nm_assert(NM_IS_SETTING_CLASS(setting_class));
     nm_assert(!setting_class->setting_info);
@@ -309,25 +311,26 @@ _nm_setting_class_commit_full(NMSettingClass *            setting_class,
     nm_assert(!sett_info->property_infos_len);
     nm_assert(!sett_info->property_infos);
 
+    property_specs =
+        g_object_class_list_properties(G_OBJECT_CLASS(setting_class), &n_property_specs);
+
     if (!properties_override) {
         override_len        = 0;
-        properties_override = _nm_sett_info_property_override_create_array();
-    } else
+        properties_override = _nm_sett_info_property_override_create_array_sized(n_property_specs);
+    } else {
         override_len = properties_override->len;
 
-    property_specs =
-        g_object_class_list_properties(G_OBJECT_CLASS(setting_class), &n_property_specs);
-
-    for (i = 0; i < properties_override->len; i++) {
-        NMSettInfoProperty *p = &g_array_index(properties_override, NMSettInfoProperty, i);
+        for (i = 0; i < override_len; i++) {
+            NMSettInfoProperty *p = &g_array_index(properties_override, NMSettInfoProperty, i);
 
-        nm_assert((!!p->name) != (!!p->param_spec));
+            nm_assert((!!p->name) != (!!p->param_spec));
 
-        if (!p->name) {
-            nm_assert(p->param_spec);
-            p->name = p->param_spec->name;
-        } else
-            nm_assert(!p->param_spec);
+            if (!p->name) {
+                nm_assert(p->param_spec);
+                p->name = p->param_spec->name;
+            } else
+                nm_assert(!p->param_spec);
+        }
     }
 
 #if NM_MORE_ASSERTS > 10