tracing/function-return-tracer: change the name into function-graph-tracer

Impact: cleanup

This patch changes the name of the "return function tracer" into
function-graph-tracer which is a more suitable name for a tracing
which makes one able to retrieve the ordered call stack during
the code flow.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

6 files changed, 138 insertions, 37 deletions

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 620feadff67a..eb9b901e0777 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -12,7 +12,7 @@ config NOP_TRACER
 config HAVE_FUNCTION_TRACER
         bool
 
-config HAVE_FUNCTION_RET_TRACER
+config HAVE_FUNCTION_GRAPH_TRACER
         bool
 
 config HAVE_FUNCTION_TRACE_MCOUNT_TEST
@@ -63,15 +63,18 @@ config FUNCTION_TRACER
           (the bootup default), then the overhead of the instructions is very
           small and not measurable even in micro-benchmarks.
 
-config FUNCTION_RET_TRACER
-        bool "Kernel Function return Tracer"
-        depends on HAVE_FUNCTION_RET_TRACER
+config FUNCTION_GRAPH_TRACER
+        bool "Kernel Function Graph Tracer"
+        depends on HAVE_FUNCTION_GRAPH_TRACER
         depends on FUNCTION_TRACER
         help
-          Enable the kernel to trace a function at its return.
-          It's first purpose is to trace the duration of functions.
-          This is done by setting the current return address on the thread
-          info structure of the current task.
+          Enable the kernel to trace a function at both its return
+          and its entry.
+          It's first purpose is to trace the duration of functions and
+          draw a call graph for each thread with some informations like
+          the return value.
+          This is done by setting the current return address on the current
+          task structure into a stack of calls.
 
 config IRQSOFF_TRACER
         bool "Interrupts-off Latency Tracer"
diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index cef4bcb4e822..08c5fe6ddc09 100644
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -29,7 +29,7 @@ obj-$(CONFIG_NOP_TRACER) += trace_nop.o
 obj-$(CONFIG_STACK_TRACER) += trace_stack.o
 obj-$(CONFIG_MMIOTRACE) += trace_mmiotrace.o
 obj-$(CONFIG_BOOT_TRACER) += trace_boot.o
-obj-$(CONFIG_FUNCTION_RET_TRACER) += trace_functions_return.o
+obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += trace_functions_graph.o
 obj-$(CONFIG_TRACE_BRANCH_PROFILING) += trace_branch.o
 obj-$(CONFIG_BTS_TRACER) += trace_bts.o
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 53042f118f23..9e19976af727 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -395,11 +395,11 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
         unsigned long ip, fl;
         unsigned long ftrace_addr;
 
-#ifdef CONFIG_FUNCTION_RET_TRACER
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
         if (ftrace_tracing_type == FTRACE_TYPE_ENTER)
                 ftrace_addr = (unsigned long)ftrace_caller;
         else
-                ftrace_addr = (unsigned long)ftrace_return_caller;
+                ftrace_addr = (unsigned long)ftrace_graph_caller;
 #else
         ftrace_addr = (unsigned long)ftrace_caller;
 #endif
@@ -1496,13 +1496,13 @@ ftrace_enable_sysctl(struct ctl_table *table, int write,
         return ret;
 }
 
-#ifdef CONFIG_FUNCTION_RET_TRACER
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 static atomic_t ftrace_retfunc_active;
 
 /* The callback that hooks the return of a function */
-trace_function_return_t ftrace_function_return =
-                        (trace_function_return_t)ftrace_stub;
+trace_function_graph_t ftrace_graph_function =
+                        (trace_function_graph_t)ftrace_stub;
 
 
 /* Try to assign a return stack array on FTRACE_RETSTACK_ALLOC_SIZE tasks. */
@@ -1549,7 +1549,7 @@ free:
 }
 
 /* Allocate a return stack for each task */
-static int start_return_tracing(void)
+static int start_graph_tracing(void)
 {
         struct ftrace_ret_stack **ret_stack_list;
         int ret;
@@ -1569,7 +1569,7 @@ static int start_return_tracing(void)
         return ret;
 }
 
-int register_ftrace_return(trace_function_return_t func)
+int register_ftrace_graph(trace_function_graph_t func)
 {
         int ret = 0;
 
@@ -1584,13 +1584,13 @@ int register_ftrace_return(trace_function_return_t func)
                 goto out;
         }
         atomic_inc(&ftrace_retfunc_active);
-        ret = start_return_tracing();
+        ret = start_graph_tracing();
         if (ret) {
                 atomic_dec(&ftrace_retfunc_active);
                 goto out;
         }
         ftrace_tracing_type = FTRACE_TYPE_RETURN;
-        ftrace_function_return = func;
+        ftrace_graph_function = func;
         ftrace_startup();
 
 out:
@@ -1598,12 +1598,12 @@ out:
         return ret;
 }
 
-void unregister_ftrace_return(void)
+void unregister_ftrace_graph(void)
 {
         mutex_lock(&ftrace_sysctl_lock);
 
         atomic_dec(&ftrace_retfunc_active);
-        ftrace_function_return = (trace_function_return_t)ftrace_stub;
+        ftrace_graph_function = (trace_function_graph_t)ftrace_stub;
         ftrace_shutdown();
         /* Restore normal tracing type */
         ftrace_tracing_type = FTRACE_TYPE_ENTER;
@@ -1612,7 +1612,7 @@ void unregister_ftrace_return(void)
 }
 
 /* Allocate a return stack for newly created task */
-void ftrace_retfunc_init_task(struct task_struct *t)
+void ftrace_graph_init_task(struct task_struct *t)
 {
         if (atomic_read(&ftrace_retfunc_active)) {
                 t->ret_stack = kmalloc(FTRACE_RETFUNC_DEPTH
@@ -1626,7 +1626,7 @@ void ftrace_retfunc_init_task(struct task_struct *t)
                 t->ret_stack = NULL;
 }
 
-void ftrace_retfunc_exit_task(struct task_struct *t)
+void ftrace_graph_exit_task(struct task_struct *t)
 {
         struct ftrace_ret_stack *ret_stack = t->ret_stack;
 
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 8df8fdd69c95..f21ab2c68fd4 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -878,15 +878,15 @@ trace_function(struct trace_array *tr, struct trace_array_cpu *data,
         ring_buffer_unlock_commit(tr->buffer, event, irq_flags);
 }