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author | Frederic Weisbecker <fweisbec@gmail.com> | 2013-07-11 20:27:43 +0200 |
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committer | Frederic Weisbecker <fweisbec@gmail.com> | 2013-08-14 17:14:48 +0200 |
commit | 1b6a259aa5ab16d8b215bfc19ff7c9ffa8858f10 (patch) | |
tree | 13aad3cfda4ff9c11e8e528685be39292c20c91d | |
parent | 73d424f9af7b571276e6284617cb59726d47bf12 (diff) | |
download | op-kernel-dev-1b6a259aa5ab16d8b215bfc19ff7c9ffa8858f10.zip op-kernel-dev-1b6a259aa5ab16d8b215bfc19ff7c9ffa8858f10.tar.gz |
context_tracking: User/kernel broundary cross trace events
This can be useful to track all kernel/user round trips.
And it's also helpful to debug the context tracking subsystem.
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>
-rw-r--r-- | include/trace/events/context_tracking.h | 58 | ||||
-rw-r--r-- | kernel/context_tracking.c | 5 |
2 files changed, 63 insertions, 0 deletions
diff --git a/include/trace/events/context_tracking.h b/include/trace/events/context_tracking.h new file mode 100644 index 0000000..ce8007c --- /dev/null +++ b/include/trace/events/context_tracking.h @@ -0,0 +1,58 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM context_tracking + +#if !defined(_TRACE_CONTEXT_TRACKING_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_CONTEXT_TRACKING_H + +#include <linux/tracepoint.h> + +DECLARE_EVENT_CLASS(context_tracking_user, + + TP_PROTO(int dummy), + + TP_ARGS(dummy), + + TP_STRUCT__entry( + __field( int, dummy ) + ), + + TP_fast_assign( + __entry->dummy = dummy; + ), + + TP_printk("%s", "") +); + +/** + * user_enter - called when the kernel resumes to userspace + * @dummy: dummy arg to make trace event macro happy + * + * This event occurs when the kernel resumes to userspace after + * an exception or a syscall. + */ +DEFINE_EVENT(context_tracking_user, user_enter, + + TP_PROTO(int dummy), + + TP_ARGS(dummy) +); + +/** + * user_exit - called when userspace enters the kernel + * @dummy: dummy arg to make trace event macro happy + * + * This event occurs when userspace enters the kernel through + * an exception or a syscall. + */ +DEFINE_EVENT(context_tracking_user, user_exit, + + TP_PROTO(int dummy), + + TP_ARGS(dummy) +); + + +#endif /* _TRACE_CONTEXT_TRACKING_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index c178226..247091b 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -20,6 +20,9 @@ #include <linux/hardirq.h> #include <linux/export.h> +#define CREATE_TRACE_POINTS +#include <trace/events/context_tracking.h> + struct static_key context_tracking_enabled = STATIC_KEY_INIT_FALSE; EXPORT_SYMBOL_GPL(context_tracking_enabled); @@ -64,6 +67,7 @@ void context_tracking_user_enter(void) local_irq_save(flags); if ( __this_cpu_read(context_tracking.state) != IN_USER) { if (__this_cpu_read(context_tracking.active)) { + trace_user_enter(0); /* * At this stage, only low level arch entry code remains and * then we'll run in userspace. We can assume there won't be @@ -159,6 +163,7 @@ void context_tracking_user_exit(void) */ rcu_user_exit(); vtime_user_exit(current); + trace_user_exit(0); } __this_cpu_write(context_tracking.state, IN_KERNEL); } |