[patch] uninline init_waitqueue_*() functions

[Ingo Molnar]

Subject: uninline init_waitqueue_*() functions
From: Ingo Molnar <mingo@xxxxxxx>

some wait.h inlines are way too large: init_waitqueue_entry() and
init_waitqueue_func_entry() generate 20-30 bytes of inlined code
per call site, and init_waitqueue_head() is 30-40 bytes (on x86).

allyesconfig vmlinux size delta:

  text            data    bss     dec          filename
  21459355        6286210 4520408 32265973     vmlinux.before
  21424564        6281246 4516912 32222722     vmlinux.after

So 34K (0.16%) of kernel text saved. Not too bad.

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

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
 include/linux/wait.h |   29 +++--------------------------
 kernel/wait.c        |   26 ++++++++++++++++++++++++--
 2 files changed, 27 insertions(+), 28 deletions(-)

Index: linux/include/linux/wait.h
===================================================================
--- linux.orig/include/linux/wait.h
+++ linux/include/linux/wait.h
@@ -77,32 +77,9 @@ 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);
-}
-
-static inline void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
-{
-	q->flags = 0;
-	q->private = p;
-	q->func = default_wake_function;
-}
-
-static inline void init_waitqueue_func_entry(wait_queue_t *q,
-					wait_queue_func_t func)
-{
-	q->flags = 0;
-	q->private = NULL;
-	q->func = func;
-}
+extern void init_waitqueue_head(wait_queue_head_t *q);
+extern void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p);
+extern void init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func);
 
 static inline int waitqueue_active(wait_queue_head_t *q)
 {
Index: linux/kernel/wait.c
===================================================================
--- linux.orig/kernel/wait.c
+++ linux/kernel/wait.c
@@ -10,9 +10,31 @@
 #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(init_waitqueue_head);
+
+void init_waitqueue_entry(wait_queue_t *q, struct task_struct *p)
+{
+	q->flags = 0;
+	q->private = p;
+	q->func = default_wake_function;
+}
+
+EXPORT_SYMBOL(init_waitqueue_entry);
+
+void init_waitqueue_func_entry(wait_queue_t *q, wait_queue_func_t func)
+{
+	q->flags = 0;
+	q->private = NULL;
+	q->func = func;
+}
 
-EXPORT_SYMBOL(waitqueue_lock_key);
+EXPORT_SYMBOL(init_waitqueue_func_entry);
 
 void fastcall add_wait_queue(wait_queue_head_t *q, wait_queue_t *wait)
 {
-
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