From: Ingo Molnar <mingo@kernel.org>
Date: Tue, 19 Feb 2013 07:45:35 +0000 (+0100)
Subject: manual merge of sched/core
X-Git-Tag: next-20130220~38^2~14
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=8c281e678b3c2b0ec2fed207fd94d596ebc4c9be;p=karo-tx-linux.git

manual merge of sched/core

Signed-off-by: Ingo Molnar <mingo@kernel.org>
---

8c281e678b3c2b0ec2fed207fd94d596ebc4c9be
diff --cc kernel/context_tracking.c
index d566aba7e801,74f68f4dc6c2..2071a46472cd
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@@ -1,40 -1,11 +1,27 @@@
 +/*
 + * Context tracking: Probe on high level context boundaries such as kernel
 + * and userspace. This includes syscalls and exceptions entry/exit.
 + *
 + * This is used by RCU to remove its dependency on the timer tick while a CPU
 + * runs in userspace.
 + *
 + *  Started by Frederic Weisbecker:
 + *
 + * Copyright (C) 2012 Red Hat, Inc., Frederic Weisbecker <fweisbec@redhat.com>
 + *
 + * Many thanks to Gilad Ben-Yossef, Paul McKenney, Ingo Molnar, Andrew Morton,
 + * Steven Rostedt, Peter Zijlstra for suggestions and improvements.
 + *
 + */
 +
  #include <linux/context_tracking.h>
+ #include <linux/kvm_host.h>
  #include <linux/rcupdate.h>
  #include <linux/sched.h>
- #include <linux/percpu.h>
  #include <linux/hardirq.h>
+ #include <linux/export.h>
  
- struct context_tracking {
- 	/*
- 	 * When active is false, probes are unset in order
- 	 * to minimize overhead: TIF flags are cleared
- 	 * and calls to user_enter/exit are ignored. This
- 	 * may be further optimized using static keys.
- 	 */
- 	bool active;
- 	enum {
- 		IN_KERNEL = 0,
- 		IN_USER,
- 	} state;
- };
- 
- static DEFINE_PER_CPU(struct context_tracking, context_tracking) = {
+ DEFINE_PER_CPU(struct context_tracking, context_tracking) = {
  #ifdef CONFIG_CONTEXT_TRACKING_FORCE
  	.active = true,
  #endif
@@@ -70,15 -31,9 +57,16 @@@ void user_enter(void
  	local_irq_save(flags);
  	if (__this_cpu_read(context_tracking.active) &&
  	    __this_cpu_read(context_tracking.state) != IN_USER) {
- 		__this_cpu_write(context_tracking.state, IN_USER);
 +		/*
 +		 * At this stage, only low level arch entry code remains and
 +		 * then we'll run in userspace. We can assume there won't be
 +		 * any RCU read-side critical section until the next call to
 +		 * user_exit() or rcu_irq_enter(). Let's remove RCU's dependency
 +		 * on the tick.
 +		 */
+ 		vtime_user_enter(current);
  		rcu_user_enter();
+ 		__this_cpu_write(context_tracking.state, IN_USER);
  	}
  	local_irq_restore(flags);
  }
@@@ -104,30 -55,31 +92,49 @@@ void user_exit(void
  
  	local_irq_save(flags);
  	if (__this_cpu_read(context_tracking.state) == IN_USER) {
- 		__this_cpu_write(context_tracking.state, IN_KERNEL);
 +		/*
 +		 * We are going to run code that may use RCU. Inform
 +		 * RCU core about that (ie: we may need the tick again).
 +		 */
  		rcu_user_exit();
+ 		vtime_user_exit(current);
+ 		__this_cpu_write(context_tracking.state, IN_KERNEL);
  	}
  	local_irq_restore(flags);
  }
  
 +
 +/**
 + * context_tracking_task_switch - context switch the syscall callbacks
 + * @prev: the task that is being switched out
 + * @next: the task that is being switched in
 + *
 + * The context tracking uses the syscall slow path to implement its user-kernel
 + * boundaries probes on syscalls. This way it doesn't impact the syscall fast
 + * path on CPUs that don't do context tracking.
 + *
 + * But we need to clear the flag on the previous task because it may later
 + * migrate to some CPU that doesn't do the context tracking. As such the TIF
 + * flag may not be desired there.
 + */
+ void guest_enter(void)
+ {
+ 	if (vtime_accounting_enabled())
+ 		vtime_guest_enter(current);
+ 	else
+ 		__guest_enter();
+ }
+ EXPORT_SYMBOL_GPL(guest_enter);
+ 
+ void guest_exit(void)
+ {
+ 	if (vtime_accounting_enabled())
+ 		vtime_guest_exit(current);
+ 	else
+ 		__guest_exit();
+ }
+ EXPORT_SYMBOL_GPL(guest_exit);
+ 
  void context_tracking_task_switch(struct task_struct *prev,
  			     struct task_struct *next)
  {