From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 18 May 2010 15:27:54 +0000 (-0700)
Subject: Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel... 
X-Git-Tag: v2.6.35-rc1~521
X-Git-Url: http://git.samba.org/samba.git/?p=sfrench%2Fcifs-2.6.git;a=commitdiff_plain;h=b8ae30ee26d379db436b0b8c8c3ff1b52f69e5d1

Merge branch 'sched-core-for-linus' of git://git./linux/kernel/git/tip/linux-2.6-tip

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (49 commits)
  stop_machine: Move local variable closer to the usage site in cpu_stop_cpu_callback()
  sched, wait: Use wrapper functions
  sched: Remove a stale comment
  ondemand: Make the iowait-is-busy time a sysfs tunable
  ondemand: Solve a big performance issue by counting IOWAIT time as busy
  sched: Intoduce get_cpu_iowait_time_us()
  sched: Eliminate the ts->idle_lastupdate field
  sched: Fold updating of the last_update_time_info into update_ts_time_stats()
  sched: Update the idle statistics in get_cpu_idle_time_us()
  sched: Introduce a function to update the idle statistics
  sched: Add a comment to get_cpu_idle_time_us()
  cpu_stop: add dummy implementation for UP
  sched: Remove rq argument to the tracepoints
  rcu: need barrier() in UP synchronize_sched_expedited()
  sched: correctly place paranioa memory barriers in synchronize_sched_expedited()
  sched: kill paranoia check in synchronize_sched_expedited()
  sched: replace migration_thread with cpu_stop
  stop_machine: reimplement using cpu_stop
  cpu_stop: implement stop_cpu[s]()
  sched: Fix select_idle_sibling() logic in select_task_rq_fair()
  ...
---

b8ae30ee26d379db436b0b8c8c3ff1b52f69e5d1
diff --cc include/linux/rcutree.h
index 48282055e83d,24e467e526b8..c0ed1c056f29
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@@ -34,9 -34,7 +34,8 @@@ struct notifier_block
  
  extern void rcu_sched_qs(int cpu);
  extern void rcu_bh_qs(int cpu);
 +extern void rcu_note_context_switch(int cpu);
  extern int rcu_needs_cpu(int cpu);
- extern int rcu_expedited_torture_stats(char *page);
  
  #ifdef CONFIG_TREE_PREEMPT_RCU
  
diff --cc kernel/sched.c
index 5cd607ec8405,b531d7934083..1d93cd0ae4d3
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@@ -2076,17 -2054,52 +2064,9 @@@ static bool migrate_task(struct task_st
  	 * If the task is not on a runqueue (and not running), then
  	 * the next wake-up will properly place the task.
  	 */
- 	if (!p->se.on_rq && !task_running(rq, p))
- 		return 0;
- 
- 	init_completion(&req->done);
- 	req->task = p;
- 	req->dest_cpu = dest_cpu;
- 	list_add(&req->list, &rq->migration_queue);
- 
- 	return 1;
+ 	return p->se.on_rq || task_running(rq, p);
  }
  
 -/*
 - * wait_task_context_switch -	wait for a thread to complete at least one
 - *				context switch.
 - *
 - * @p must not be current.
 - */
 -void wait_task_context_switch(struct task_struct *p)
 -{
 -	unsigned long nvcsw, nivcsw, flags;
 -	int running;
 -	struct rq *rq;
 -
 -	nvcsw	= p->nvcsw;
 -	nivcsw	= p->nivcsw;
 -	for (;;) {
 -		/*
 -		 * The runqueue is assigned before the actual context
 -		 * switch. We need to take the runqueue lock.
 -		 *
 -		 * We could check initially without the lock but it is
 -		 * very likely that we need to take the lock in every
 -		 * iteration.
 -		 */
 -		rq = task_rq_lock(p, &flags);
 -		running = task_running(rq, p);
 -		task_rq_unlock(rq, &flags);
 -
 -		if (likely(!running))
 -			break;
 -		/*
 -		 * The switch count is incremented before the actual
 -		 * context switch. We thus wait for two switches to be
 -		 * sure at least one completed.
 -		 */
 -		if ((p->nvcsw - nvcsw) > 1)
 -			break;
 -		if ((p->nivcsw - nivcsw) > 1)
 -			break;
 -
 -		cpu_relax();
 -	}
 -}
 -
  /*
   * wait_task_inactive - wait for a thread to unschedule.
   *