astobj2: Reduce memory overhead.

Reduce options to 2-bit field, magic to 30 bit field.  Move ref_counter
next to options and explicitly use int32_t so the fields will pack.

This reduces memory overhead for every ao2 object by 8 bytes on x86_64.

Change-Id: Idc1baabb35ec3b3d8de463c4fa3011eaf7fcafb5

diff --git a/main/astobj2.c b/main/astobj2.c
index 63058e19e34c5ca12968bab36caa254fe1503193..ea4ad02351580a4aba614f4ebaf05b473c70badf 100644 (file)
--- a/main/astobj2.c
+++ b/main/astobj2.c
@@ -48,7 +48,6 @@ static FILE *ref_log;
  * The magic number is used for consistency check.
  */
 struct __priv_data {
-       int ref_counter;
        ao2_destructor_fn destructor_fn;
        /*! This field is used for astobj2 and ao2_weakproxy objects to reference each other */
        void *weakptr;
@@ -56,15 +55,17 @@ struct __priv_data {
        /*! User data size for stats */
        size_t data_size;
 #endif
+       /*! Number of references held for this object */
+       int32_t ref_counter;
        /*! The ao2 object option flags */
-       uint32_t options;
+       uint32_t options:2;
        /*! magic number.  This is used to verify that a pointer passed in is a
         *  valid astobj2 or ao2_weak reference */
-       uint32_t magic;
+       uint32_t magic:30;
 };
 
-#define        AO2_MAGIC       0xa570b123
-#define        AO2_WEAK        0xa570b122
+#define        AO2_MAGIC       0x3a70b123
+#define        AO2_WEAK        0x3a70b122
 #define IS_AO2_MAGIC_BAD(p) (AO2_MAGIC != (p->priv_data.magic | 1))
 
 /*!
@@ -465,8 +466,8 @@ int __ao2_ref(void *user_data, int delta,
        struct astobj2_lock *obj_mutex;
        struct astobj2_rwlock *obj_rwlock;
        struct astobj2_lockobj *obj_lockobj;
-       int current_value;
-       int ret;
+       int32_t current_value;
+       int32_t ret;
        struct ao2_weakproxy *weakproxy = NULL;
 
        if (obj == NULL) {
@@ -488,7 +489,7 @@ int __ao2_ref(void *user_data, int delta,
        }
 
        /* we modify with an atomic operation the reference counter */
-       ret = ast_atomic_fetchadd_int(&obj->priv_data.ref_counter, delta);
+       ret = ast_atomic_fetch_add(&obj->priv_data.ref_counter, delta, __ATOMIC_RELAXED);
        current_value = ret + delta;
 
 #ifdef AO2_DEBUG
@@ -541,7 +542,7 @@ int __ao2_ref(void *user_data, int delta,
                        /* We just reached or went over the excessive ref count trigger */
                        snprintf(excessive_ref_buf, sizeof(excessive_ref_buf),
                                "Excessive refcount %d reached on ao2 object %p",
-                               current_value, user_data);
+                               (int)current_value, user_data);
                        ast_log(__LOG_ERROR, file, line, func, "%s\n", excessive_ref_buf);
 
                        __ast_assert_failed(0, excessive_ref_buf, file, line, func);
@@ -550,7 +551,7 @@ int __ao2_ref(void *user_data, int delta,
                if (ref_log && tag) {
                        fprintf(ref_log, "%p,%s%d,%d,%s,%d,%s,%d,%s\n", user_data,
                                (delta < 0 ? "" : "+"), delta, ast_get_tid(),
-                               file, line, func, ret, tag);
+                               file, line, func, (int)ret, tag);
                        fflush(ref_log);
                }
                return ret;
@@ -559,7 +560,7 @@ int __ao2_ref(void *user_data, int delta,
        /* this case must never happen */
        if (current_value < 0) {
                ast_log(__LOG_ERROR, file, line, func,
-                       "Invalid refcount %d on ao2 object %p\n", current_value, user_data);
+                       "Invalid refcount %d on ao2 object %p\n", (int)current_value, user_data);
                if (ref_log) {
                        /* Log to ref_log invalid even if (tag == NULL) */
                        fprintf(ref_log, "%p,%d,%d,%s,%d,%s,**invalid**,%s\n",
@@ -692,8 +693,8 @@ static void *internal_ao2_alloc(size_t data_size, ao2_destructor_fn destructor_f
        }
 
        /* Initialize common ao2 values. */
-       obj->priv_data.ref_counter = 1;
        obj->priv_data.destructor_fn = destructor_fn;   /* can be NULL */
+       obj->priv_data.ref_counter = 1;
        obj->priv_data.options = options;
        obj->priv_data.magic = AO2_MAGIC;