commit 65f382fd0c8fa483713c0971de9f1dfb4cf1ad9c
author Frederic Weisbecker <fweisbec@gmail.com> Thu Jul 11 19:12:32 2013 +0200
committer Frederic Weisbecker <fweisbec@gmail.com> Wed Aug 14 17:12:46 2013 +0200
tree dec89c43fcfb4934611bae4855293428382856b9
parent d84d27a491880b9902b45c09be8d9e9464fb9b74

context_tracking: Ground setup for static key use

Prepare for using a static key in the context tracking subsystem.
This will help optimizing the off case on its many users:

* user_enter, user_exit, exception_enter, exception_exit, guest_enter,
  guest_exit, vtime_*()

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Kevin Hilman <khilman@linaro.org>

include/linux/context_tracking.h

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index 1ae37c7..c138c24 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -4,6 +4,7 @@
 #include <linux/sched.h>
 #include <linux/percpu.h>
 #include <linux/vtime.h>
+#include <linux/static_key.h>
 #include <asm/ptrace.h>
 
 struct context_tracking {
@@ -22,6 +23,7 @@
 
 
 #ifdef CONFIG_CONTEXT_TRACKING
+extern struct static_key context_tracking_enabled;
 DECLARE_PER_CPU(struct context_tracking, context_tracking);
 
 static inline bool context_tracking_in_user(void)
@@ -67,6 +69,14 @@
 						struct task_struct *next) { }
 #endif /* !CONFIG_CONTEXT_TRACKING */
 
+
+#ifdef CONFIG_CONTEXT_TRACKING_FORCE
+extern void context_tracking_init(void);
+#else
+static inline void context_tracking_init(void) { }
+#endif /* CONFIG_CONTEXT_TRACKING_FORCE */
+
+
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
 extern void guest_enter(void);
 extern void guest_exit(void);