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authorFrederic Weisbecker <fweisbec@gmail.com>2012-11-27 19:33:25 +0100
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-11-30 11:40:07 -0800
commit91d1aa43d30505b0b825db8898ffc80a8eca96c7 (patch)
tree911636f846d800c8a44efd540842dc726ec7c191 /include/linux/context_tracking.h
parent4e79752c25ec221ac1e28f8875b539ed7631a0db (diff)
context_tracking: New context tracking susbsystem
Create a new subsystem that probes on kernel boundaries to keep track of the transitions between level contexts with two basic initial contexts: user or kernel. This is an abstraction of some RCU code that use such tracking to implement its userspace extended quiescent state. We need to pull this up from RCU into this new level of indirection because this tracking is also going to be used to implement an "on demand" generic virtual cputime accounting. A necessary step to shutdown the tick while still accounting the cputime. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Gilad Ben-Yossef <gilad@benyossef.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> [ paulmck: fix whitespace error and email address. ] Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'include/linux/context_tracking.h')
-rw-r--r--include/linux/context_tracking.h18
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
new file mode 100644
index 000000000000..e24339ccb7f0
--- /dev/null
+++ b/include/linux/context_tracking.h
@@ -0,0 +1,18 @@
+#ifndef _LINUX_CONTEXT_TRACKING_H
+#define _LINUX_CONTEXT_TRACKING_H
+
+#ifdef CONFIG_CONTEXT_TRACKING
+#include <linux/sched.h>
+
+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 void user_enter(void) { }
+static inline void user_exit(void) { }
+static inline void context_tracking_task_switch(struct task_struct *prev,
+ struct task_struct *next) { }
+#endif /* !CONFIG_CONTEXT_TRACKING */
+
+#endif