[patch 02/19] hrtimers: clean up callback tracking

[Thomas Gleixner]

From: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

Reintroduce ktimers feature "optimized away" by the ktimers review process:
remove the curr_timer pointer from the cpu-base and use the hrtimer state.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>

Index: linux-2.6.19-rc5-mm1/include/linux/hrtimer.h
===================================================================
--- linux-2.6.19-rc5-mm1.orig/include/linux/hrtimer.h	2006-11-09 21:06:07.000000000 +0100
+++ linux-2.6.19-rc5-mm1/include/linux/hrtimer.h	2006-11-09 21:06:09.000000000 +0100
@@ -136,7 +136,6 @@ struct hrtimer_cpu_base {
 	spinlock_t			lock;
 	struct lock_class_key		lock_key;
 	struct hrtimer_clock_base	clock_base[HRTIMER_MAX_CLOCK_BASES];
-	struct hrtimer			*curr_timer;
 };
 
 /*
Index: linux-2.6.19-rc5-mm1/kernel/hrtimer.c
===================================================================
--- linux-2.6.19-rc5-mm1.orig/kernel/hrtimer.c	2006-11-09 21:06:07.000000000 +0100
+++ linux-2.6.19-rc5-mm1/kernel/hrtimer.c	2006-11-09 21:06:09.000000000 +0100
@@ -150,8 +150,6 @@ static void hrtimer_get_softirq_time(str
  */
 #ifdef CONFIG_SMP
 
-#define set_curr_timer(b, t)		do { (b)->curr_timer = (t); } while (0)
-
 /*
  * We are using hashed locking: holding per_cpu(hrtimer_bases)[n].lock
  * means that all timers which are tied to this base via timer->base are
@@ -205,7 +203,7 @@ switch_hrtimer_base(struct hrtimer *time
 		 * completed. There is no conflict as we hold the lock until
 		 * the timer is enqueued.
 		 */
-		if (unlikely(base->cpu_base->curr_timer == timer))
+		if (unlikely(timer->state & HRTIMER_STATE_CALLBACK))
 			return base;
 
 		/* See the comment in lock_timer_base() */
@@ -219,8 +217,6 @@ switch_hrtimer_base(struct hrtimer *time
 
 #else /* CONFIG_SMP */
 
-#define set_curr_timer(b, t)		do { } while (0)
-
 static inline struct hrtimer_clock_base *
 lock_hrtimer_base(const struct hrtimer *timer, unsigned long *flags)
 {
@@ -654,7 +650,6 @@ static inline void run_hrtimer_queue(str
 			break;
 
 		fn = timer->function;
-		set_curr_timer(cpu_base, timer);
 		__remove_hrtimer(timer, base, HRTIMER_STATE_CALLBACK);
 		spin_unlock_irq(&cpu_base->lock);
 
@@ -668,7 +663,6 @@ static inline void run_hrtimer_queue(str
 			enqueue_hrtimer(timer, base);
 		}
 	}
-	set_curr_timer(cpu_base, NULL);
 	spin_unlock_irq(&cpu_base->lock);
 }
 
@@ -855,8 +849,6 @@ static void migrate_hrtimers(int cpu)
 	spin_lock(&old_base->lock);
 
 	for (i = 0; i < HRTIMER_MAX_CLOCK_BASES; i++) {
-		BUG_ON(old_base->curr_timer);
-
 		migrate_hrtimer_list(&old_base->clock_base[i],
 				     &new_base->clock_base[i]);
 	}

--

-
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