diff mbox

[4/7] tracing/function: Introduce persistent trace option

Message ID 1340753009-12483-4-git-send-email-anton.vorontsov@linaro.org
State New
Headers show

Commit Message

Anton Vorontsov June 26, 2012, 11:23 p.m. UTC 
This patch introduces 'func_ptrace' option, now available in
/sys/kernel/debug/tracing/options when function tracer
is selected.

The patch also adds some tiny code that calls back to pstore
to record the trace. The callback is no-op when PSTORE=n.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
---
 kernel/trace/trace_functions.c |   25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

Comments

Steven Rostedt June 27, 2012, 12:40 p.m. UTC | #1 
On Tue, 2012-06-26 at 16:23 -0700, Anton Vorontsov wrote:
>  
> @@ -219,6 +232,8 @@ static int func_set_flag(u32 old_flags, u32 bit, int set)
>  
>  		return 0;
>  	}
> +	if (bit == TRACE_FUNC_OPT_PSTORE)
> +		return 0;

Perhaps this should be a switch() statement, or at least put a
 } else if () {

As it can't be bit == TRACE_FUNC_OPT_STACK and bit ==
TRACE_FUNC_OPT_PSTORE.

-- Steve

>  
>  	return -EINVAL;
>  }
Anton Vorontsov July 9, 2012, 11:44 p.m. UTC | #2 
On Wed, Jun 27, 2012 at 08:40:12AM -0400, Steven Rostedt wrote:
> On Tue, 2012-06-26 at 16:23 -0700, Anton Vorontsov wrote:
> > @@ -219,6 +232,8 @@ static int func_set_flag(u32 old_flags, u32 bit, int set)
> >  
> >  		return 0;
> >  	}
> > +	if (bit == TRACE_FUNC_OPT_PSTORE)
> > +		return 0;
> 
> Perhaps this should be a switch() statement, or at least put a
>  } else if () {
> 
> As it can't be bit == TRACE_FUNC_OPT_STACK and bit ==
> TRACE_FUNC_OPT_PSTORE.

Yup, thanks for the idea. I'll start using 'else if' at first, and then
will convert it to a switch statement via a separate patch, that way I'll
not clobber the functional patch with cosmetic changes.

Thanks,
diff mbox

Patch

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index c7b0c6a..269627c 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -13,6 +13,7 @@ 
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/ftrace.h>
+#include <linux/pstore.h>
 #include <linux/fs.h>
 
 #include "trace.h"
@@ -74,6 +75,14 @@  function_trace_call_preempt_only(unsigned long ip, unsigned long parent_ip)
 	preempt_enable_notrace();
 }
 
+/* Our two options */
+enum {
+	TRACE_FUNC_OPT_STACK	= 0x1,
+	TRACE_FUNC_OPT_PSTORE	= 0x2,
+};
+
+static struct tracer_flags func_flags;
+
 static void
 function_trace_call(unsigned long ip, unsigned long parent_ip)
 {
@@ -97,6 +106,12 @@  function_trace_call(unsigned long ip, unsigned long parent_ip)
 	disabled = atomic_inc_return(&data->disabled);
 
 	if (likely(disabled == 1)) {
+		/*
+		 * So far tracing doesn't support multiple buffers, so
+		 * we make an explicit call for now.
+		 */
+		if (unlikely(func_flags.val & TRACE_FUNC_OPT_PSTORE))
+			pstore_ftrace_call(ip, parent_ip);
 		pc = preempt_count();
 		trace_function(tr, ip, parent_ip, flags, pc);
 	}
@@ -158,15 +173,13 @@  static struct ftrace_ops trace_stack_ops __read_mostly =
 	.flags = FTRACE_OPS_FL_GLOBAL,
 };
 
-/* Our two options */
-enum {
-	TRACE_FUNC_OPT_STACK = 0x1,
-};
-
 static struct tracer_opt func_opts[] = {
 #ifdef CONFIG_STACKTRACE
 	{ TRACER_OPT(func_stack_trace, TRACE_FUNC_OPT_STACK) },
 #endif
+#ifdef CONFIG_PSTORE_FTRACE
+	{ TRACER_OPT(func_pstore, TRACE_FUNC_OPT_PSTORE) },
+#endif
 	{ } /* Always set a last empty entry */
 };
 
@@ -219,6 +232,8 @@  static int func_set_flag(u32 old_flags, u32 bit, int set)
 
 		return 0;
 	}
+	if (bit == TRACE_FUNC_OPT_PSTORE)
+		return 0;
 
 	return -EINVAL;
 }