[Asterisk-code-review] astobj2: Reduce memory overhead. (asterisk[master])

[Corey Farrell]

Corey Farrell has uploaded this change for review. ( https://gerrit.asterisk.org/10294


Change subject: astobj2: Reduce memory overhead.
......................................................................

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
---
M main/astobj2.c
1 file changed, 9 insertions(+), 8 deletions(-)



  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/94/10294/1

diff --git a/main/astobj2.c b/main/astobj2.c
index 63058e1..ce016a6 100644
--- a/main/astobj2.c
+++ b/main/astobj2.c
@@ -48,7 +48,6 @@
  * 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 @@
 	/*! 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 @@
 	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 @@
 	}
 
 	/* 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

-- 
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Gerrit-Project: asterisk
Gerrit-Branch: master
Gerrit-MessageType: newchange
Gerrit-Change-Id: Idc1baabb35ec3b3d8de463c4fa3011eaf7fcafb5
Gerrit-Change-Number: 10294
Gerrit-PatchSet: 1
Gerrit-Owner: Corey Farrell <git at cfware.com>
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