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tracing/stack_trace: Skip 4 instead of 3 when using ftrace_ops_list_func

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When using ftrace_ops_list_func, we should skip 4 instead of 3,
to avoid ftrace_call+0x5/0xb appearing in the stack trace:

        Depth    Size   Location    (110 entries)
        -----    ----   --------
  0)     2956       0   update_curr+0xe/0x1e0
  1)     2956      68   ftrace_call+0x5/0xb
  2)     2888      92   enqueue_entity+0x53/0xe80
  3)     2796      80   enqueue_task_fair+0x47/0x7e0
  4)     2716      28   enqueue_task+0x45/0x70
  5)     2688      12   activate_task+0x22/0x30

Add a function using_ftrace_ops_list_func() to test for this while keeping
ftrace_ops_list_func to remain static.

Link: http://lkml.kernel.org/p/1398006644-5935-2-git-send-email-wangjiaxing@insigma.com.cn

Signed-off-by: Jiaxing Wang <wangjiaxing@insigma.com.cn>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Jiaxing Wang 2014-04-20 23:10:43 +08:00 committed by Steven Rostedt
parent ad1438a076
commit 7eea4fce02
3 changed files with 12 additions and 2 deletions
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5
kernel/trace/ftrace.c
View File

@ -313,6 +313,11 @@ static void update_ftrace_function(void)
ftrace_trace_function = func;
}
int using_ftrace_ops_list_func(void)
{
return ftrace_trace_function == ftrace_ops_list_func;
}
static void add_ftrace_ops(struct ftrace_ops **list, struct ftrace_ops *ops)
{
ops->next = *list;

1
kernel/trace/trace.h
View File

@ -830,6 +830,7 @@ void ftrace_destroy_function_files(struct trace_array *tr);
void ftrace_init_global_array_ops(struct trace_array *tr);
void ftrace_init_array_ops(struct trace_array *tr, ftrace_func_t func);
void ftrace_reset_array_ops(struct trace_array *tr);
int using_ftrace_ops_list_func(void);
#else
static inline int ftrace_trace_task(struct task_struct *task)
{

8
kernel/trace/trace_stack.c
View File

@ -85,8 +85,12 @@ check_stack(unsigned long ip, unsigned long *stack)
max_stack_size = this_size;
max_stack_trace.nr_entries = 0;
max_stack_trace.skip = 3;
max_stack_trace.nr_entries = 0;
if (using_ftrace_ops_list_func())
max_stack_trace.skip = 4;
else
max_stack_trace.skip = 3;
save_stack_trace(&max_stack_trace);