[patch] uninline init_waitqueue_*() functions

From: Ingo Molnar
Date: Wed Jul 05 2006 - 04:53:08 EST


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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