X-Git-Url: http://drtracing.org/?a=blobdiff_plain;f=kernel%2Fsched.c;h=0236958addcbac72ca908c6be8ac74275a512ad7;hb=b0d8aa081bcb2d396a257ae5b3be8c1b3006bfa4;hp=6acf749d33369545310a94ff0fd52341d821bfd0;hpb=e9f76354ce83a20c7768ad37caa033f6506b4f96;p=deliverable%2Flinux.git

diff --git a/kernel/sched.c b/kernel/sched.c
index 6acf749d3336..0236958addcb 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1867,16 +1867,24 @@ migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
 /*
  * wait_task_inactive - wait for a thread to unschedule.
  *
+ * If @match_state is nonzero, it's the @p->state value just checked and
+ * not expected to change.  If it changes, i.e. @p might have woken up,
+ * then return zero.  When we succeed in waiting for @p to be off its CPU,
+ * we return a positive number (its total switch count).  If a second call
+ * a short while later returns the same number, the caller can be sure that
+ * @p has remained unscheduled the whole time.
+ *
  * The caller must ensure that the task *will* unschedule sometime soon,
  * else this function might spin for a *long* time. This function can't
  * be called with interrupts off, or it may introduce deadlock with
  * smp_call_function() if an IPI is sent by the same process we are
  * waiting to become inactive.
  */
-void wait_task_inactive(struct task_struct *p)
+unsigned long wait_task_inactive(struct task_struct *p, long match_state)
 {
 	unsigned long flags;
 	int running, on_rq;
+	unsigned long ncsw;
 	struct rq *rq;
 
 	for (;;) {
@@ -1899,8 +1907,11 @@ void wait_task_inactive(struct task_struct *p)
 		 * return false if the runqueue has changed and p
 		 * is actually now running somewhere else!
 		 */
-		while (task_running(rq, p))
+		while (task_running(rq, p)) {
+			if (match_state && unlikely(p->state != match_state))
+				return 0;
 			cpu_relax();
+		}
 
 		/*
 		 * Ok, time to look more closely! We need the rq
@@ -1910,8 +1921,20 @@ void wait_task_inactive(struct task_struct *p)
 		rq = task_rq_lock(p, &flags);
 		running = task_running(rq, p);
 		on_rq = p->se.on_rq;
+		ncsw = 0;
+		if (!match_state || p->state == match_state) {
+			ncsw = p->nivcsw + p->nvcsw;
+			if (unlikely(!ncsw))
+				ncsw = 1;
+		}
 		task_rq_unlock(rq, &flags);
 
+		/*
+		 * If it changed from the expected state, bail out now.
+		 */
+		if (unlikely(!ncsw))
+			break;
+
 		/*
 		 * Was it really running after all now that we
 		 * checked with the proper locks actually held?
@@ -1944,6 +1967,8 @@ void wait_task_inactive(struct task_struct *p)
 		 */
 		break;
 	}
+
+	return ncsw;
 }
 
 /***
@@ -4046,6 +4071,8 @@ void account_user_time(struct task_struct *p, cputime_t cputime)
 		cpustat->nice = cputime64_add(cpustat->nice, tmp);
 	else
 		cpustat->user = cputime64_add(cpustat->user, tmp);
+	/* Account for user time used */
+	acct_update_integrals(p);
 }
 
 /*
@@ -6387,7 +6414,7 @@ static struct notifier_block __cpuinitdata migration_notifier = {
 	.priority = 10
 };
 
-void __init migration_init(void)
+static int __init migration_init(void)
 {
 	void *cpu = (void *)(long)smp_processor_id();
 	int err;
@@ -6397,7 +6424,10 @@ void __init migration_init(void)
 	BUG_ON(err == NOTIFY_BAD);
 	migration_call(&migration_notifier, CPU_ONLINE, cpu);
 	register_cpu_notifier(&migration_notifier);
+
+	return err;
 }
+early_initcall(migration_init);
 #endif
 
 #ifdef CONFIG_SMP