From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 17 Jul 2011 21:56:42 +0200
Subject: trace: Add migrate-disabled counter to tracing output

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 include/linux/trace_events.h |    2 ++
 kernel/trace/trace.c         |   26 +++++++++++++++++++-------
 kernel/trace/trace_events.c  |    1 +
 kernel/trace/trace_output.c  |    5 +++++
 4 files changed, 27 insertions(+), 7 deletions(-)

--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -67,6 +67,7 @@ struct trace_entry {
 	unsigned char		flags;
 	unsigned char		preempt_count;
 	int			pid;
+	unsigned char		migrate_disable;
 };
 
 #define TRACE_EVENT_TYPE_MAX						\
@@ -153,6 +154,7 @@ static inline void tracing_generic_entry
 						unsigned int trace_ctx)
 {
 	entry->preempt_count		= trace_ctx & 0xff;
+	entry->migrate_disable		= (trace_ctx >> 8) & 0xff;
 	entry->pid			= current->pid;
 	entry->type			= type;
 	entry->flags =			trace_ctx >> 16;
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2578,6 +2578,15 @@ enum print_line_t trace_handle_return(st
 }
 EXPORT_SYMBOL_GPL(trace_handle_return);
 
+static unsigned short migration_disable_value(void)
+{
+#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT_RT)
+	return current->migration_disabled;
+#else
+	return 0;
+#endif
+}
+
 unsigned int tracing_gen_ctx_irq_test(unsigned int irqs_status)
 {
 	unsigned int trace_flags = irqs_status;
@@ -2596,7 +2605,8 @@ unsigned int tracing_gen_ctx_irq_test(un
 		trace_flags |= TRACE_FLAG_NEED_RESCHED;
 	if (test_preempt_need_resched())
 		trace_flags |= TRACE_FLAG_PREEMPT_RESCHED;
-	return (trace_flags << 16) | (pc & 0xff);
+	return (trace_flags << 16) | (pc & 0xff) |
+		(migration_disable_value() & 0xff) << 8;
 }
 
 struct ring_buffer_event *
@@ -3802,9 +3812,10 @@ static void print_lat_help_header(struct
 		    "#                  | / _----=> need-resched    \n"
 		    "#                  || / _---=> hardirq/softirq \n"
 		    "#                  ||| / _--=> preempt-depth   \n"
-		    "#                  |||| /     delay            \n"
-		    "#  cmd     pid     ||||| time  |   caller      \n"
-		    "#     \\   /        |||||  \\    |   /         \n");
+		    "#                  |||| / _-=> migrate-disable \n"
+		    "#                  ||||| /     delay           \n"
+		    "#  cmd     pid     |||||| time  |   caller     \n"
+		    "#     \\   /        ||||||  \\    |    /       \n");
 }
 
 static void print_event_info(struct array_buffer *buf, struct seq_file *m)
@@ -3842,9 +3853,10 @@ static void print_func_help_header_irq(s
 	seq_printf(m, "#                            %.*s / _----=> need-resched\n", prec, space);
 	seq_printf(m, "#                            %.*s| / _---=> hardirq/softirq\n", prec, space);
 	seq_printf(m, "#                            %.*s|| / _--=> preempt-depth\n", prec, space);
-	seq_printf(m, "#                            %.*s||| /     delay\n", prec, space);
-	seq_printf(m, "#           TASK-PID  %.*s CPU#  ||||   TIMESTAMP  FUNCTION\n", prec, "     TGID   ");
-	seq_printf(m, "#              | |    %.*s   |   ||||      |         |\n", prec, "       |    ");
+	seq_printf(m, "#                            %.*s||| / _-=> migrate-disable\n", prec, space);
+	seq_printf(m, "#                            %.*s|||| /     delay\n", prec, space);
+	seq_printf(m, "#           TASK-PID  %.*s CPU#  |||||  TIMESTAMP  FUNCTION\n", prec, "     TGID   ");
+	seq_printf(m, "#              | |    %.*s   |   |||||     |         |\n", prec, "       |    ");
 }
 
 void
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -183,6 +183,7 @@ static int trace_define_common_fields(vo
 	__common_field(unsigned char, flags);
 	__common_field(unsigned char, preempt_count);
 	__common_field(int, pid);
+	__common_field(unsigned char, migrate_disable);
 
 	return ret;
 }
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -487,6 +487,11 @@ int trace_print_lat_fmt(struct trace_seq
 	else
 		trace_seq_putc(s, '.');
 
+	if (entry->migrate_disable)
+		trace_seq_printf(s, "%x", entry->migrate_disable);
+	else
+		trace_seq_putc(s, '.');
+
 	return !trace_seq_has_overflowed(s);
 }