lkml.org 
[lkml]   [2008]   [Dec]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 4/5] ftrace: function graph return for function entry

* Steven Rostedt <rostedt@goodmis.org> wrote:

> From: Steven Rostedt <srostedt@redhat.com>
>
> Impact: feature, let entry function decide to trace or not
>
> This patch lets the graph tracer entry function decide if the tracing
> should be done at the end as well. This requires all function graph
> entry functions return 1 if it should trace, or 0 if the return should
> not be traced.

> diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
> index 47aa5f0..cef05a2 100644
> --- a/arch/x86/kernel/entry_64.S
> +++ b/arch/x86/kernel/entry_64.S
> @@ -119,6 +119,9 @@ ENTRY(mcount)
> #ifdef CONFIG_FUNCTION_GRAPH_TRACER
> cmpq $ftrace_stub, ftrace_graph_return
> jnz ftrace_graph_caller
> +
> + cmpq $ftrace_graph_entry_stub, ftrace_graph_entry
> + jnz ftrace_graph_caller

hm, that's in the hotpath. What's the point of this? Do we want some sort
of configuration vector that allows per function graphing versus
entry-only traces?

Ingo


\
 
 \ /
  Last update: 2008-12-03 09:15    [from the cache]
©2003-2011 Jasper Spaans. Advertise on this site