qobject: Replace property list with GHashTable

ARM GICv3 systems with large number of CPUs create lots of IRQ pins. Since every pin is represented as a property, number of these properties becomes very large. Every property add first makes sure there's no duplicates. Traversing the list becomes very slow, therefore qemu initialization takes significant time (several seconds for e. g. 16 CPUs).

This patch replaces list with GHashTable, making lookup very fast. The only drawback is that object_child_foreach() and object_child_foreach_recursive() cannot modify their objects during traversal, since GHashTableIter does not have modify-safe version. However, the code seems not to modify objects via these functions.

Signed-off-by Pavel Fedin <[email protected]>

---
 include/qom/object.h |  4 +--
 qmp.c                |  8 +++--
 qom/object.c         | 98 +++++++++++++++++++++++-----------------------------
 vl.c                 |  4 ++-
 4 files changed, 54 insertions(+), 60 deletions(-)

include/qom/object.h +2 -2

index be7280c..b100923 100644
@@ -345,7 +345,7 @@ typedef struct ObjectProperty
     ObjectPropertyRelease *release;
     void *opaque;
 
-    QTAILQ_ENTRY(ObjectProperty) node;
+    Object *obj;
 } ObjectProperty;
 
 /**

@@ -405,7 +405,7 @@ struct Object
     /*< private >*/
     ObjectClass *class;
     ObjectFree *free;
-    QTAILQ_HEAD(, ObjectProperty) properties;
+    GHashTable *properties;
     uint32_t ref;
     Object *parent;
 };

qmp.c +6 -2

index 057a7cb..683f427 100644
@@ -207,6 +207,7 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp)
     Object *obj;
     bool ambiguous = false;
     ObjectPropertyInfoList *props = NULL;
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     obj = object_resolve_path(path, &ambiguous);

@@ -220,7 +221,8 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp)
         return NULL;
     }
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         ObjectPropertyInfoList *entry = g_malloc0(sizeof(*entry));
 
         entry->value = g_malloc0(sizeof(ObjectPropertyInfo));

@@ -499,6 +501,7 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
 {
     ObjectClass *klass;
     Object *obj;
+    GHashTableIter iter;
     ObjectProperty *prop;
     DevicePropertyInfoList *prop_list = NULL;
 

@@ -517,7 +520,8 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
 
     obj = object_new(typename);
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         DevicePropertyInfo *info;
         DevicePropertyInfoList *entry;
 

qom/object.c +43 -55

index 4805328..9649243 100644
@@ -326,6 +326,20 @@ static void object_post_init_with_type(Object *obj, TypeImpl *ti)
     }
 }
 
+static void property_destroy(gpointer data)
+{
+    ObjectProperty *prop = data;
+
+    if (prop->release) {
+        prop->release(prop->obj, prop->name, prop->opaque);
+    }
+
+    g_free(prop->name);
+    g_free(prop->type);
+    g_free(prop->description);
+    g_free(prop);
+}
+
 void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
 {
     Object *obj = data;

@@ -340,7 +354,8 @@ void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
     memset(obj, 0, type->instance_size);
     obj->class = type->class;
     object_ref(obj);
-    QTAILQ_INIT(&obj->properties);
+    obj->properties = g_hash_table_new_full(g_str_hash, g_str_equal,
+                                            NULL, property_destroy);
     object_init_with_type(obj, type);
     object_post_init_with_type(obj, type);
 }

@@ -357,40 +372,19 @@ static inline bool object_property_is_child(ObjectProperty *prop)
     return strstart(prop->type, "child<", NULL);
 }
 
-static void object_property_del_all(Object *obj)
+static gboolean object_property_del_child(gpointer key, gpointer value,
+                                          gpointer child)
 {
-    while (!QTAILQ_EMPTY(&obj->properties)) {
-        ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
-
-        QTAILQ_REMOVE(&obj->properties, prop, node);
+    ObjectProperty *prop = value;
 
-        if (prop->release) {
-            prop->release(obj, prop->name, prop->opaque);
-        }
-
-        g_free(prop->name);
-        g_free(prop->type);
-        g_free(prop->description);
-        g_free(prop);
-    }
-}
-
-static void object_property_del_child(Object *obj, Object *child, Error **errp)
-{
-    ObjectProperty *prop;
-
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (object_property_is_child(prop) && prop->opaque == child) {
-            object_property_del(obj, prop->name, errp);
-            break;
-        }
-    }
+    return object_property_is_child(prop) && prop->opaque == child;
 }
 
 void object_unparent(Object *obj)
 {
     if (obj->parent) {
-        object_property_del_child(obj->parent, obj, NULL);
+        g_hash_table_foreach_remove(obj->properties,
+                                    object_property_del_child, obj);
     }
 }
 

@@ -410,7 +404,7 @@ static void object_finalize(void *data)
     Object *obj = data;
     TypeImpl *ti = obj->class->type;
 
-    object_property_del_all(obj);
+    g_hash_table_unref(obj->properties);
     object_deinit(obj, ti);
 
     g_assert(obj->ref == 0);

@@ -779,10 +773,12 @@ static int do_object_child_foreach(Object *obj,
                                    int (*fn)(Object *child, void *opaque),
                                    void *opaque, bool recurse)
 {
-    ObjectProperty *prop, *next;
+    GHashTableIter iter;
+    ObjectProperty *prop;
     int ret = 0;
 
-    QTAILQ_FOREACH_SAFE(prop, &obj->properties, node, next) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (object_property_is_child(prop)) {
             Object *child = prop->opaque;
 

@@ -879,13 +875,11 @@ object_property_add(Object *obj, const char *name, const char *type,
         return ret;
     }
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (strcmp(prop->name, name) == 0) {
-            error_setg(errp, "attempt to add duplicate property '%s'"
+    if (g_hash_table_contains(obj->properties, name)) {
+        error_setg(errp, "attempt to add duplicate property '%s'"
                        " to object (type '%s')", name,
                        object_get_typename(obj));
-            return NULL;
-        }
+        return NULL;
     }
 
     prop = g_malloc0(sizeof(*prop));

@@ -897,8 +891,9 @@ object_property_add(Object *obj, const char *name, const char *type,
     prop->set = set;
     prop->release = release;
     prop->opaque = opaque;
+    prop->obj = obj;
 
-    QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
+    g_hash_table_insert(obj->properties, prop->name, prop);
     return prop;
 }
 

@@ -907,10 +902,9 @@ ObjectProperty *object_property_find(Object *obj, const char *name,
 {
     ObjectProperty *prop;
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (strcmp(prop->name, name) == 0) {
-            return prop;
-        }
+    prop = g_hash_table_lookup(obj->properties, name);
+    if (prop) {
+        return prop;
     }
 
     error_setg(errp, "Property '.%s' not found", name);

@@ -919,21 +913,11 @@ ObjectProperty *object_property_find(Object *obj, const char *name,
 
 void object_property_del(Object *obj, const char *name, Error **errp)
 {
-    ObjectProperty *prop = object_property_find(obj, name, errp);
-    if (prop == NULL) {
+    if (g_hash_table_remove(obj->properties, name)) {
         return;
     }
 
-    if (prop->release) {
-        prop->release(obj, name, prop->opaque);
-    }
-
-    QTAILQ_REMOVE(&obj->properties, prop, node);
-
-    g_free(prop->name);
-    g_free(prop->type);
-    g_free(prop->description);
-    g_free(prop);
+    error_setg(errp, "Property '.%s' not found", name);
 }
 
 void object_property_get(Object *obj, Visitor *v, const char *name,

@@ -1453,11 +1437,13 @@ void object_property_add_const_link(Object *obj, const char *name,
 gchar *object_get_canonical_path_component(Object *obj)
 {
     ObjectProperty *prop = NULL;
+    GHashTableIter iter;
 
     g_assert(obj);
     g_assert(obj->parent != NULL);
 
-    QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
+    g_hash_table_iter_init(&iter, obj->parent->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (!object_property_is_child(prop)) {
             continue;
         }

@@ -1541,11 +1527,13 @@ static Object *object_resolve_partial_path(Object *parent,
                                               bool *ambiguous)
 {
     Object *obj;
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     obj = object_resolve_abs_path(parent, parts, typename, 0);
 
-    QTAILQ_FOREACH(prop, &parent->properties, node) {
+    g_hash_table_iter_init(&iter, parent->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         Object *found;
 
         if (!object_property_is_child(prop)) {

vl.c +3 -1

index e211f6a..7065d5f 100644
@@ -1506,13 +1506,15 @@ MachineInfoList *qmp_query_machines(Error **errp)
 
 static int machine_help_func(QemuOpts *opts, MachineState *machine)
 {
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     if (!qemu_opt_has_help_opt(opts)) {
         return 0;
     }
 
-    QTAILQ_FOREACH(prop, &OBJECT(machine)->properties, node) {
+    g_hash_table_iter_init(&iter, OBJECT(machine)->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (!prop->set) {
             continue;
         }

qom/object.c static inline bool object_property_is_child(ObjectProperty *prop) · line 386

Quoted 5 lines

void object_unparent(Object *obj)

 {
     if (obj->parent) {

qom/object.c +1 -1

-        object_property_del_child(obj->parent, obj, NULL);
+        g_hash_table_foreach_remove(obj->properties,

Quoted 3 lines

+                                    object_property_del_child, obj);
     }

}

Shouldn't this help similarly with the problem that 94649d423e worked around? (Although that patch has standalone merits of course.)

David,

Quoted 12 lines · Pavel Fedin

ARM GICv3 systems with large number of CPUs create lots of IRQ pins. Since every pin is represented as a property, number of these properties becomes very large. Every property add first makes sure there's no duplicates. Traversing the list becomes very slow, therefore qemu initialization takes significant time (several seconds for e. g. 16 CPUs).

This patch replaces list with GHashTable, making lookup very fast. The only drawback is that object_child_foreach() and object_child_foreach_recursive() cannot modify their objects during traversal, since GHashTableIter does not have modify-safe version. However, the code seems not to modify objects via these functions.

Quoted 7 lines

Signed-off-by Pavel Fedin <[email protected]>

---
 include/qom/object.h |  4 +--
 qmp.c                |  8 +++--
 qom/object.c         | 98 +++++++++++++++++++++++-----------------------------
 vl.c                 |  4 ++-
 4 files changed, 54 insertions(+), 60 deletions(-)

Shouldn't this help similarly with the problem that 94649d423e worked around? (Although that patch has standalone merits of course.)

Thanks
Laszlo

Quoted 286 lines

include/qom/object.h +2 -2

index be7280c..b100923 100644
@@ -345,7 +345,7 @@ typedef struct ObjectProperty
     ObjectPropertyRelease *release;
     void *opaque;
 
-    QTAILQ_ENTRY(ObjectProperty) node;
+    Object *obj;
 } ObjectProperty;
 
 /**

@@ -405,7 +405,7 @@ struct Object
     /*< private >*/
     ObjectClass *class;
     ObjectFree *free;
-    QTAILQ_HEAD(, ObjectProperty) properties;
+    GHashTable *properties;
     uint32_t ref;
     Object *parent;
 };

qmp.c +6 -2

index 057a7cb..683f427 100644
@@ -207,6 +207,7 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp)
     Object *obj;
     bool ambiguous = false;
     ObjectPropertyInfoList *props = NULL;
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     obj = object_resolve_path(path, &ambiguous);

@@ -220,7 +221,8 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp)
         return NULL;
     }
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         ObjectPropertyInfoList *entry = g_malloc0(sizeof(*entry));
 
         entry->value = g_malloc0(sizeof(ObjectPropertyInfo));

@@ -499,6 +501,7 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
 {
     ObjectClass *klass;
     Object *obj;
+    GHashTableIter iter;
     ObjectProperty *prop;
     DevicePropertyInfoList *prop_list = NULL;
 

@@ -517,7 +520,8 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
 
     obj = object_new(typename);
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         DevicePropertyInfo *info;
         DevicePropertyInfoList *entry;
 

qom/object.c +43 -55

index 4805328..9649243 100644
@@ -326,6 +326,20 @@ static void object_post_init_with_type(Object *obj, TypeImpl *ti)
     }
 }
 
+static void property_destroy(gpointer data)
+{
+    ObjectProperty *prop = data;
+
+    if (prop->release) {
+        prop->release(prop->obj, prop->name, prop->opaque);
+    }
+
+    g_free(prop->name);
+    g_free(prop->type);
+    g_free(prop->description);
+    g_free(prop);
+}
+
 void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
 {
     Object *obj = data;

@@ -340,7 +354,8 @@ void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
     memset(obj, 0, type->instance_size);
     obj->class = type->class;
     object_ref(obj);
-    QTAILQ_INIT(&obj->properties);
+    obj->properties = g_hash_table_new_full(g_str_hash, g_str_equal,
+                                            NULL, property_destroy);
     object_init_with_type(obj, type);
     object_post_init_with_type(obj, type);
 }

@@ -357,40 +372,19 @@ static inline bool object_property_is_child(ObjectProperty *prop)
     return strstart(prop->type, "child<", NULL);
 }
 
-static void object_property_del_all(Object *obj)
+static gboolean object_property_del_child(gpointer key, gpointer value,
+                                          gpointer child)
 {
-    while (!QTAILQ_EMPTY(&obj->properties)) {
-        ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
-
-        QTAILQ_REMOVE(&obj->properties, prop, node);
+    ObjectProperty *prop = value;
 
-        if (prop->release) {
-            prop->release(obj, prop->name, prop->opaque);
-        }
-
-        g_free(prop->name);
-        g_free(prop->type);
-        g_free(prop->description);
-        g_free(prop);
-    }
-}
-
-static void object_property_del_child(Object *obj, Object *child, Error **errp)
-{
-    ObjectProperty *prop;
-
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (object_property_is_child(prop) && prop->opaque == child) {
-            object_property_del(obj, prop->name, errp);
-            break;
-        }
-    }
+    return object_property_is_child(prop) && prop->opaque == child;
 }
 
 void object_unparent(Object *obj)
 {
     if (obj->parent) {
-        object_property_del_child(obj->parent, obj, NULL);
+        g_hash_table_foreach_remove(obj->properties,
+                                    object_property_del_child, obj);
     }
 }
 

@@ -410,7 +404,7 @@ static void object_finalize(void *data)
     Object *obj = data;
     TypeImpl *ti = obj->class->type;
 
-    object_property_del_all(obj);
+    g_hash_table_unref(obj->properties);
     object_deinit(obj, ti);
 
     g_assert(obj->ref == 0);

@@ -779,10 +773,12 @@ static int do_object_child_foreach(Object *obj,
                                    int (*fn)(Object *child, void *opaque),
                                    void *opaque, bool recurse)
 {
-    ObjectProperty *prop, *next;
+    GHashTableIter iter;
+    ObjectProperty *prop;
     int ret = 0;
 
-    QTAILQ_FOREACH_SAFE(prop, &obj->properties, node, next) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (object_property_is_child(prop)) {
             Object *child = prop->opaque;
 

@@ -879,13 +875,11 @@ object_property_add(Object *obj, const char *name, const char *type,
         return ret;
     }
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (strcmp(prop->name, name) == 0) {
-            error_setg(errp, "attempt to add duplicate property '%s'"
+    if (g_hash_table_contains(obj->properties, name)) {
+        error_setg(errp, "attempt to add duplicate property '%s'"
                        " to object (type '%s')", name,
                        object_get_typename(obj));
-            return NULL;
-        }
+        return NULL;
     }
 
     prop = g_malloc0(sizeof(*prop));

@@ -897,8 +891,9 @@ object_property_add(Object *obj, const char *name, const char *type,
     prop->set = set;
     prop->release = release;
     prop->opaque = opaque;
+    prop->obj = obj;
 
-    QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
+    g_hash_table_insert(obj->properties, prop->name, prop);
     return prop;
 }
 

@@ -907,10 +902,9 @@ ObjectProperty *object_property_find(Object *obj, const char *name,
 {
     ObjectProperty *prop;
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (strcmp(prop->name, name) == 0) {
-            return prop;
-        }
+    prop = g_hash_table_lookup(obj->properties, name);
+    if (prop) {
+        return prop;
     }
 
     error_setg(errp, "Property '.%s' not found", name);

@@ -919,21 +913,11 @@ ObjectProperty *object_property_find(Object *obj, const char *name,
 
 void object_property_del(Object *obj, const char *name, Error **errp)
 {
-    ObjectProperty *prop = object_property_find(obj, name, errp);
-    if (prop == NULL) {
+    if (g_hash_table_remove(obj->properties, name)) {
         return;
     }
 
-    if (prop->release) {
-        prop->release(obj, name, prop->opaque);
-    }
-
-    QTAILQ_REMOVE(&obj->properties, prop, node);
-
-    g_free(prop->name);
-    g_free(prop->type);
-    g_free(prop->description);
-    g_free(prop);
+    error_setg(errp, "Property '.%s' not found", name);
 }
 
 void object_property_get(Object *obj, Visitor *v, const char *name,

@@ -1453,11 +1437,13 @@ void object_property_add_const_link(Object *obj, const char *name,
 gchar *object_get_canonical_path_component(Object *obj)
 {
     ObjectProperty *prop = NULL;
+    GHashTableIter iter;
 
     g_assert(obj);
     g_assert(obj->parent != NULL);
 
-    QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
+    g_hash_table_iter_init(&iter, obj->parent->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (!object_property_is_child(prop)) {
             continue;
         }

@@ -1541,11 +1527,13 @@ static Object *object_resolve_partial_path(Object *parent,
                                               bool *ambiguous)
 {
     Object *obj;
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     obj = object_resolve_abs_path(parent, parts, typename, 0);
 
-    QTAILQ_FOREACH(prop, &parent->properties, node) {
+    g_hash_table_iter_init(&iter, parent->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         Object *found;
 
         if (!object_property_is_child(prop)) {

vl.c +3 -1

index e211f6a..7065d5f 100644
@@ -1506,13 +1506,15 @@ MachineInfoList *qmp_query_machines(Error **errp)
 
 static int machine_help_func(QemuOpts *opts, MachineState *machine)
 {
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     if (!qemu_opt_has_help_opt(opts)) {
         return 0;
     }
 
-    QTAILQ_FOREACH(prop, &OBJECT(machine)->properties, node) {
+    g_hash_table_iter_init(&iter, OBJECT(machine)->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (!prop->set) {
             continue;
         }

ARM GICv3 systems with large number of CPUs create lots of IRQ pins. Since every pin is represented as a property, number of these properties becomes very large. Every property add first makes sure there's no duplicates. Traversing the list becomes very slow, therefore qemu initialization takes significant time (several seconds for e. g. 16 CPUs).

This patch replaces list with GHashTable, making lookup very fast. The only drawback is that object_child_foreach() and object_child_foreach_recursive() cannot modify their objects during traversal, since GHashTableIter does not have modify-safe version. However, the code seems not to modify objects via these functions.

Signed-off-by Pavel Fedin <[email protected]>

---
 include/qom/object.h |  4 +--
 qmp.c                |  8 +++--
 qom/object.c         | 98 +++++++++++++++++++++++-----------------------------
 vl.c                 |  4 ++-
 4 files changed, 54 insertions(+), 60 deletions(-)

include/qom/object.h +0 -0

index be7280c..b100923 100644

include/qom/object.h +0 -0

     uint32_t ref;
     Object *parent;
 };

qmp.c +6 -2

index 057a7cb..683f427 100644
@@ -207,6 +207,7 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp)
     Object *obj;
     bool ambiguous = false;
     ObjectPropertyInfoList *props = NULL;
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     obj = object_resolve_path(path, &ambiguous);

@@ -220,7 +221,8 @@ ObjectPropertyInfoList *qmp_qom_list(const char *path, Error **errp)
         return NULL;
     }
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         ObjectPropertyInfoList *entry = g_malloc0(sizeof(*entry));
 
         entry->value = g_malloc0(sizeof(ObjectPropertyInfo));

@@ -499,6 +501,7 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
 {
     ObjectClass *klass;
     Object *obj;
+    GHashTableIter iter;
     ObjectProperty *prop;
     DevicePropertyInfoList *prop_list = NULL;
 

@@ -517,7 +520,8 @@ DevicePropertyInfoList *qmp_device_list_properties(const char *typename,
 
     obj = object_new(typename);
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         DevicePropertyInfo *info;
         DevicePropertyInfoList *entry;
 

qom/object.c +19 -26

index 4805328..9649243 100644
@@ -326,6 +326,20 @@ static void object_post_init_with_type(Object *obj, TypeImpl *ti)
     }
 }
 
+static void property_destroy(gpointer data)
+{
+    ObjectProperty *prop = data;
+
+    if (prop->release) {
+        prop->release(prop->obj, prop->name, prop->opaque);
+    }
+
+    g_free(prop->name);
+    g_free(prop->type);
+    g_free(prop->description);
+    g_free(prop);
+}
+
 void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
 {
     Object *obj = data;

@@ -340,7 +354,8 @@ void object_initialize_with_type(void *data, size_t size, TypeImpl *type)
     memset(obj, 0, type->instance_size);
     obj->class = type->class;
     object_ref(obj);
-    QTAILQ_INIT(&obj->properties);
+    obj->properties = g_hash_table_new_full(g_str_hash, g_str_equal,
+                                            NULL, property_destroy);
     object_init_with_type(obj, type);
     object_post_init_with_type(obj, type);
 }

@@ -357,40 +372,19 @@ static inline bool object_property_is_child(ObjectProperty *prop)
     return strstart(prop->type, "child<", NULL);
 }
 
-static void object_property_del_all(Object *obj)
+static gboolean object_property_del_child(gpointer key, gpointer value,
+                                          gpointer child)
 {
-    while (!QTAILQ_EMPTY(&obj->properties)) {
-        ObjectProperty *prop = QTAILQ_FIRST(&obj->properties);
-
-        QTAILQ_REMOVE(&obj->properties, prop, node);
+    ObjectProperty *prop = value;
 
-        if (prop->release) {
-            prop->release(obj, prop->name, prop->opaque);
-        }
-
-        g_free(prop->name);
-        g_free(prop->type);
-        g_free(prop->description);
-        g_free(prop);
-    }
-}
-
-static void object_property_del_child(Object *obj, Object *child, Error **errp)
-{
-    ObjectProperty *prop;
-
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (object_property_is_child(prop) && prop->opaque == child) {
-            object_property_del(obj, prop->name, errp);
-            break;
-        }

qom/object.c +21 -27

     }
 }
 

@@ -410,7 +404,7 @@ static void object_finalize(void *data)
     Object *obj = data;
     TypeImpl *ti = obj->class->type;
 
-    object_property_del_all(obj);
+    g_hash_table_unref(obj->properties);
     object_deinit(obj, ti);
 
     g_assert(obj->ref == 0);

@@ -779,10 +773,12 @@ static int do_object_child_foreach(Object *obj,
                                    int (*fn)(Object *child, void *opaque),
                                    void *opaque, bool recurse)
 {
-    ObjectProperty *prop, *next;
+    GHashTableIter iter;
+    ObjectProperty *prop;
     int ret = 0;
 
-    QTAILQ_FOREACH_SAFE(prop, &obj->properties, node, next) {
+    g_hash_table_iter_init(&iter, obj->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (object_property_is_child(prop)) {
             Object *child = prop->opaque;
 

@@ -879,13 +875,11 @@ object_property_add(Object *obj, const char *name, const char *type,
         return ret;
     }
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (strcmp(prop->name, name) == 0) {
-            error_setg(errp, "attempt to add duplicate property '%s'"
+    if (g_hash_table_contains(obj->properties, name)) {
+        error_setg(errp, "attempt to add duplicate property '%s'"
                        " to object (type '%s')", name,
                        object_get_typename(obj));
-            return NULL;
-        }
+        return NULL;
     }
 
     prop = g_malloc0(sizeof(*prop));

@@ -897,8 +891,9 @@ object_property_add(Object *obj, const char *name, const char *type,
     prop->set = set;
     prop->release = release;
     prop->opaque = opaque;
+    prop->obj = obj;
 
-    QTAILQ_INSERT_TAIL(&obj->properties, prop, node);
+    g_hash_table_insert(obj->properties, prop->name, prop);
     return prop;
 }
 

@@ -907,10 +902,9 @@ ObjectProperty *object_property_find(Object *obj, const char *name,
 {
     ObjectProperty *prop;
 
-    QTAILQ_FOREACH(prop, &obj->properties, node) {
-        if (strcmp(prop->name, name) == 0) {
-            return prop;
-        }
+    prop = g_hash_table_lookup(obj->properties, name);
+    if (prop) {
+        return prop;
     }
 
     error_setg(errp, "Property '.%s' not found", name);

@@ -919,21 +913,11 @@ ObjectProperty *object_property_find(Object *obj, const char *name,
 
 void object_property_del(Object *obj, const char *name, Error **errp)
 {
-    ObjectProperty *prop = object_property_find(obj, name, errp);
-    if (prop == NULL) {
+    if (g_hash_table_remove(obj->properties, name)) {
         return;
     }
 
-    if (prop->release) {
-        prop->release(obj, name, prop->opaque);
-    }
-
-    QTAILQ_REMOVE(&obj->properties, prop, node);
-
-    g_free(prop->name);
-    g_free(prop->type);
-    g_free(prop->description);
-    g_free(prop);
+    error_setg(errp, "Property '.%s' not found", name);
 }
 
 void object_property_get(Object *obj, Visitor *v, const char *name,

@@ -1453,11 +1437,13 @@ void object_property_add_const_link(Object *obj, const char *name,
 gchar *object_get_canonical_path_component(Object *obj)
 {
     ObjectProperty *prop = NULL;
+    GHashTableIter iter;
 
     g_assert(obj);
     g_assert(obj->parent != NULL);
 
-    QTAILQ_FOREACH(prop, &obj->parent->properties, node) {
+    g_hash_table_iter_init(&iter, obj->parent->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (!object_property_is_child(prop)) {
             continue;
         }

@@ -1541,11 +1527,13 @@ static Object *object_resolve_partial_path(Object *parent,
                                               bool *ambiguous)
 {
     Object *obj;
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     obj = object_resolve_abs_path(parent, parts, typename, 0);
 
-    QTAILQ_FOREACH(prop, &parent->properties, node) {
+    g_hash_table_iter_init(&iter, parent->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         Object *found;
 
         if (!object_property_is_child(prop)) {

vl.c +3 -1

index e211f6a..7065d5f 100644
@@ -1506,13 +1506,15 @@ MachineInfoList *qmp_query_machines(Error **errp)
 
 static int machine_help_func(QemuOpts *opts, MachineState *machine)
 {
+    GHashTableIter iter;
     ObjectProperty *prop;
 
     if (!qemu_opt_has_help_opt(opts)) {
         return 0;
     }
 
-    QTAILQ_FOREACH(prop, &OBJECT(machine)->properties, node) {
+    g_hash_table_iter_init(&iter, OBJECT(machine)->properties);
+    while (g_hash_table_iter_next(&iter, NULL, (gpointer *)&prop)) {
         if (!prop->set) {
             continue;
         }

Hmm.. modifying a child object internally should be fine, shouldn't it? IIUC only trying to remove it, change the key or the pointer to the value should be problematic.

How much extra memory does each Object take with no (or few) properties by using a hash table rather than a simple list here?