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authorFrederic Weisbecker <fweisbec@gmail.com>2013-07-12 02:15:49 +0200
committerFrederic Weisbecker <fweisbec@gmail.com>2013-08-14 17:14:51 +0200
commite7358b3bc0d7fcec0e7a724477f06db2b0c68e21 (patch)
treec572630fa67687845330d53a2fd12d24c7d83014 /include/linux/context_tracking_state.h
parent54461562c90e0ac104764c5a9de637fd9151a1c1 (diff)
context_tracking: Split low level state headers
We plan to use the context tracking static key on inline vtime APIs. For this we need to include the context tracking headers from those of vtime. However vtime headers need to stay low level because they are included in hardirq.h that mostly contains standalone definitions. But context_tracking.h includes sched.h for a few task_struct references, therefore it wouldn't be sensible to include it from vtime.h To solve this, lets split the context tracking headers and move out the pure state definitions that only require a few low level headers. We can safely include that small part in vtime.h later. 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>
Diffstat (limited to 'include/linux/context_tracking_state.h')
-rw-r--r--include/linux/context_tracking_state.h39
1 files changed, 39 insertions, 0 deletions
diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h
new file mode 100644
index 000000000000..0f1979d0674f
--- /dev/null
+++ b/include/linux/context_tracking_state.h
@@ -0,0 +1,39 @@
+#ifndef _LINUX_CONTEXT_TRACKING_STATE_H
+#define _LINUX_CONTEXT_TRACKING_STATE_H
+
+#include <linux/percpu.h>
+#include <linux/static_key.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 ctx_state {
+ IN_KERNEL = 0,
+ IN_USER,
+ } state;
+};
+
+#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)
+{
+ return __this_cpu_read(context_tracking.state) == IN_USER;
+}
+
+static inline bool context_tracking_active(void)
+{
+ return __this_cpu_read(context_tracking.active);
+}
+#else
+static inline bool context_tracking_in_user(void) { return false; }
+static inline bool context_tracking_active(void) { return false; }
+#endif /* CONFIG_CONTEXT_TRACKING */
+
+#endif