[patch] uninline init_waitqueue_head()

[Ingo Molnar <mingo@elte.hu>]

* Andrew Morton <akpm@osdl.org> wrote:

> On my x86_64 typicalconfig
> (http://www.zip.com.au/~akpm/linux/patches/stuff/config-x)
> 
> everything inlined:
> 
>    text    data     bss     dec     hex filename
> 4079169  702440  280184 5061793  4d3ca1 vmlinux
> 
> uninline init_waitqueue_head:
> 
> 4076921  702456  280184 5059561  4d33e9 vmlinux
> 
> uninline init_waitqueue_head+init_waitqueue_entry
> 
> box:/usr/src/25> size vmlinux
>    text    data     bss     dec     hex filename
> 4077017  702472  280184 5059673  4d3459 vmlinux
> 
> uninline init_waitqueue_head+init_waitqueue_entry+init_waitqueue_func_entry
> 
> box:/usr/src/25> size vmlinux
>    text    data     bss     dec     hex filename
> 4077128  702496  280184 5059808  4d34e0 vmlinux
> 
> So we only want to uninline init_waitqueue_head().

yeah, i played with that too and concluded that it's a small win on i386
:-) Anyway, updated patch below - i agree that the biggest item is
init_waitqueue_head().

	Ingo

---------------->
Subject: uninline init_waitqueue_head()
From: Ingo Molnar <mingo@elte.hu>

uninline more wait.h inline functions.

allyesconfig vmlinux size delta:

  text            data    bss     dec          filename
  20736884        6073834 3075176 29885894     vmlinux.before
  20721009        6073966 3075176 29870151     vmlinux.after

~18 bytes per callsite, 15K of text size (~0.1%) saved.

(as an added bonus this also removes a lockdep annotation.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 include/linux/wait.h |   12 +-----------
 kernel/wait.c        |    8 ++++++--
 2 files changed, 7 insertions(+), 13 deletions(-)

Index: linux/include/linux/wait.h
===================================================================
--- linux.orig/include/linux/wait.h
+++ linux/include/linux/wait.h
@@ -77,17 +77,7 @@ struct task_struct;
 #define __WAIT_BIT_KEY_INITIALIZER(word, bit)				\
 	{ .flags = word, .bit_nr = bit, }
 
-/*
- * lockdep: we want one lock-class for all waitqueue locks.
- */
-extern struct lock_class_key waitqueue_lock_key;
-
-static inline void init_waitqueue_head(wait_queue_head_t *q)
-{
-	spin_lock_init(&q->lock);
-	lockdep_set_class(&q->lock, &waitqueue_lock_key);
-	INIT_LIST_HEAD(&q->task_list);
-}
+extern void init_waitqueue_head(wait_queue_head_t *q);
 
 static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
 {
Index: linux/kernel/wait.c
===================================================================
--- linux.orig/kernel/wait.c
+++ linux/kernel/wait.c
@@ -10,9 +10,13 @@
 #include <linux/wait.h>
 #include <linux/hash.h>
 
-struct lock_class_key waitqueue_lock_key;
+void init_waitqueue_head(wait_queue_head_t *q)
+{
+	spin_lock_init(&q->lock);
+	INIT_LIST_HEAD(&q->task_list);
+}
 
-EXPORT_SYMBOL(waitqueue_lock_key);
+EXPORT_SYMBOL(init_waitqueue_head);
 
 void fastcall add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)
 {