linux-kernel - [patch 1/6] epoll keyed wakeups v2 - add __wake_up_locked_key() and __wake_up_sync

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Date:	Sun, 01 Feb 2009 12:04:23 -0800
From:	Davide Libenzi <davidel@...ilserver.org>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>,
	Ingo Molnar <mingo@...e.hu>, David Miller <davem@...emloft.net>
Subject: [patch 1/6] epoll keyed wakeups v2 - add __wake_up_locked_key() and __wake_up_sync_key()

Nothing revolutionary here. Just using the available "key" that our
wakeup core already support.  The __wake_up_locked_key() was no brainer,
since both __wake_up_locked() and __wake_up_locked_key() are thin
wrappers around __wake_up_common().
The __wake_up_sync() function had a body, so the choice was between
borrowing the body for __wake_up_sync_key() and calling it from
__wake_up_sync(), or make an inline and calling it from both. I chose
the former since in most archs it all resolves to "mov $0, REG; jmp ADDR".



Signed-off-by: Davide Libenzi <davidel@...ilserver.org>


- Davide


---
 include/linux/wait.h |    7 +++++--
 kernel/sched.c       |   23 +++++++++++++++++++----
 2 files changed, 24 insertions(+), 6 deletions(-)

Index: linux-2.6.mod/include/linux/wait.h
===================================================================
--- linux-2.6.mod.orig/include/linux/wait.h	2009-01-31 14:55:14.000000000 -0800
+++ linux-2.6.mod/include/linux/wait.h	2009-01-31 15:08:09.000000000 -0800
@@ -133,8 +133,11 @@ static inline void __remove_wait_queue(w
 }
 
 void __wake_up(wait_queue_head_t *q, unsigned int mode, int nr, void *key);
-extern void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
-extern void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
+void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key);
+void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, int nr,
+			void *key);
+void __wake_up_locked(wait_queue_head_t *q, unsigned int mode);
+void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr);
 void __wake_up_bit(wait_queue_head_t *, void *, int);
 int __wait_on_bit(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
 int __wait_on_bit_lock(wait_queue_head_t *, struct wait_bit_queue *, int (*)(void *), unsigned);
Index: linux-2.6.mod/kernel/sched.c
===================================================================
--- linux-2.6.mod.orig/kernel/sched.c	2009-01-31 14:55:14.000000000 -0800
+++ linux-2.6.mod/kernel/sched.c	2009-01-31 15:22:02.000000000 -0800
@@ -4727,11 +4727,17 @@ void __wake_up_locked(wait_queue_head_t 
 	__wake_up_common(q, mode, 1, 0, NULL);
 }
 
+void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
+{
+	__wake_up_common(q, mode, 1, 0, key);
+}
+
 /**
- * __wake_up_sync - wake up threads blocked on a waitqueue.
+ * __wake_up_sync_key - wake up threads blocked on a waitqueue.
  * @q: the waitqueue
  * @mode: which threads
  * @nr_exclusive: how many wake-one or wake-many threads to wake up
+ * @key: opaque value to be passed to wakeup targets
  *
  * The sync wakeup differs that the waker knows that it will schedule
  * away soon, so while the target thread will be woken up, it will not
@@ -4740,8 +4746,8 @@ void __wake_up_locked(wait_queue_head_t 
  *
  * On UP it can prevent extra preemption.
  */
-void
-__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
+void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
+			int nr_exclusive, void *key)
 {
 	unsigned long flags;
 	int sync = 1;
@@ -4753,9 +4759,18 @@ __wake_up_sync(wait_queue_head_t *q, uns
 		sync = 0;
 
 	spin_lock_irqsave(&q->lock, flags);
-	__wake_up_common(q, mode, nr_exclusive, sync, NULL);
+	__wake_up_common(q, mode, nr_exclusive, sync, key);
 	spin_unlock_irqrestore(&q->lock, flags);
 }
+EXPORT_SYMBOL_GPL(__wake_up_sync_key);
+
+/*
+ * __wake_up_sync - see __wake_up_sync_key()
+ */
+void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
+{
+	__wake_up_sync_key(q, mode, nr_exclusive, NULL);
+}
 EXPORT_SYMBOL_GPL(__wake_up_sync);	/* For internal use only */
 
 /**

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