context_tracking: Export context state for generic vtime

Export the context state: whether we run in user / kernel
from the context tracking subsystem point of view.

This is going to be used by the generic virtual cputime
accounting subsystem that is needed to implement the full
dynticks.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index e24339ccb7f04a066dd52b7a88cd8a7d06c265bc..b28d161c1091908b9395df4e3ad73e6d88518966 100644 (file)
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -3,12 +3,40 @@
 
 #ifdef CONFIG_CONTEXT_TRACKING
 #include <linux/sched.h>
+#include <linux/percpu.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;
+};
+
+DECLARE_PER_CPU(struct context_tracking, context_tracking);
+
+static inline bool context_tracking_in_user(void)
+{
+       return __this_cpu_read(context_tracking.state) == IN_USER;
+}
+
+static inline bool context_tracking_active(void)
+{
+       return __this_cpu_read(context_tracking.active);
+}
 
 extern void user_enter(void);
 extern void user_exit(void);
 extern void context_tracking_task_switch(struct task_struct *prev,
                                         struct task_struct *next);
 #else
+static inline bool context_tracking_in_user(void) { return false; }
 static inline void user_enter(void) { }
 static inline void user_exit(void) { }
 static inline void context_tracking_task_switch(struct task_struct *prev,

diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c
index e0e07fd55508eeca456e7c8e6567dec1d25a9586..54f471e536dca2ed3e682c900cba3fdca555cab8 100644 (file)
--- a/kernel/context_tracking.c
+++ b/kernel/context_tracking.c
@@ -1,24 +1,10 @@
 #include <linux/context_tracking.h>
 #include <linux/rcupdate.h>
 #include <linux/sched.h>
-#include <linux/percpu.h>
 #include <linux/hardirq.h>
 
-struct context_tracking {
-       /*
-        * When active is false, hooks are not set 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