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authorSteven Rostedt <rostedt@goodmis.org>2008-11-26 00:16:24 -0500
committerIngo Molnar <mingo@elte.hu>2008-11-26 06:52:54 +0100
commit5a45cfe1c64862e8cd3b0d79d7c4ba71c3118915 (patch)
tree0a7edf3a9dc88d74b7c7053445ac8aff033a75fa /kernel
parentdf4fc31558dd2a3a30292ddb3a64c2a5befcec73 (diff)
ftrace: use code patching for ftrace graph tracer
Impact: more efficient code for ftrace graph tracer This patch uses the dynamic patching, when available, to patch the function graph code into the kernel. This patch will ease the way for letting both function tracing and function graph tracing run together. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ftrace.c35
1 files changed, 16 insertions, 19 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 00d98c65fad..5f7c8642d58 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -281,6 +281,8 @@ enum {
FTRACE_UPDATE_TRACE_FUNC = (1 << 2),
FTRACE_ENABLE_MCOUNT = (1 << 3),
FTRACE_DISABLE_MCOUNT = (1 << 4),
+ FTRACE_START_FUNC_RET = (1 << 5),
+ FTRACE_STOP_FUNC_RET = (1 << 6),
};
static int ftrace_filtered;
@@ -465,14 +467,7 @@ __ftrace_replace_code(struct dyn_ftrace *rec, int enable)
unsigned long ip, fl;
unsigned long ftrace_addr;
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
- if (ftrace_tracing_type == FTRACE_TYPE_ENTER)
- ftrace_addr = (unsigned long)ftrace_caller;
- else
- ftrace_addr = (unsigned long)ftrace_graph_caller;
-#else
ftrace_addr = (unsigned long)ftrace_caller;
-#endif
ip = rec->ip;
@@ -605,6 +600,11 @@ static int __ftrace_modify_code(void *data)
if (*command & FTRACE_UPDATE_TRACE_FUNC)
ftrace_update_ftrace_func(ftrace_trace_function);
+ if (*command & FTRACE_START_FUNC_RET)
+ ftrace_enable_ftrace_graph_caller();
+ else if (*command & FTRACE_STOP_FUNC_RET)
+ ftrace_disable_ftrace_graph_caller();
+
return 0;
}
@@ -629,10 +629,8 @@ static void ftrace_startup_enable(int command)
ftrace_run_update_code(command);
}
-static void ftrace_startup(void)
+static void ftrace_startup(int command)
{
- int command = 0;
-
if (unlikely(ftrace_disabled))
return;
@@ -645,10 +643,8 @@ static void ftrace_startup(void)
mutex_unlock(&ftrace_start_lock);
}
-static void ftrace_shutdown(void)
+static void ftrace_shutdown(int command)
{
- int command = 0;
-
if (unlikely(ftrace_disabled))
return;
@@ -1453,8 +1449,9 @@ device_initcall(ftrace_nodyn_init);
static inline int ftrace_init_dyn_debugfs(struct dentry *d_tracer) { return 0; }
static inline void ftrace_startup_enable(int command) { }
-# define ftrace_startup() do { } while (0)
-# define ftrace_shutdown() do { } while (0)
+/* Keep as macros so we do not need to define the commands */
+# define ftrace_startup(command) do { } while (0)
+# define ftrace_shutdown(command) do { } while (0)
# define ftrace_startup_sysctl() do { } while (0)
# define ftrace_shutdown_sysctl() do { } while (0)
#endif /* CONFIG_DYNAMIC_FTRACE */
@@ -1585,7 +1582,7 @@ int register_ftrace_function(struct ftrace_ops *ops)
}
ret = __register_ftrace_function(ops);
- ftrace_startup();
+ ftrace_startup(0);
out:
mutex_unlock(&ftrace_sysctl_lock);
@@ -1604,7 +1601,7 @@ int unregister_ftrace_function(struct ftrace_ops *ops)
mutex_lock(&ftrace_sysctl_lock);
ret = __unregister_ftrace_function(ops);
- ftrace_shutdown();
+ ftrace_shutdown(0);
mutex_unlock(&ftrace_sysctl_lock);
return ret;
@@ -1751,7 +1748,7 @@ int register_ftrace_graph(trace_func_graph_ret_t retfunc,
ftrace_tracing_type = FTRACE_TYPE_RETURN;
ftrace_graph_return = retfunc;
ftrace_graph_entry = entryfunc;
- ftrace_startup();
+ ftrace_startup(FTRACE_START_FUNC_RET);
out:
mutex_unlock(&ftrace_sysctl_lock);
@@ -1765,7 +1762,7 @@ void unregister_ftrace_graph(void)
atomic_dec(&ftrace_graph_active);
ftrace_graph_return = (trace_func_graph_ret_t)ftrace_stub;
ftrace_graph_entry = (trace_func_graph_ent_t)ftrace_stub;
- ftrace_shutdown();
+ ftrace_shutdown(FTRACE_STOP_FUNC_RET);
/* Restore normal tracing type */
ftrace_tracing_type = FTRACE_TYPE_ENTER;