On 2020-07-22 00:43, Steven Rostedt wrote:
On Tue, 21 Jul 2020 12:37:33 -0400
Steven Rostedt <[email protected]> wrote:
On Mon, 20 Jul 2020 10:21:15 +0800
Tingwei Zhang <[email protected]> wrote:
> Only function traces can be exported to other destinations currently.
> This patch exports event trace as well.
>
> Signed-off-by: Tingwei Zhang <[email protected]>
> ---
> kernel/trace/trace.c | 24 +++++++++++++-----------
> 1 file changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index bb62269724d5..aef6330836e2 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -2697,17 +2697,6 @@ int tracepoint_printk_sysctl(struct ctl_table
*table, int write,
> return ret;
> }
>
> -void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
> -{
> - if (static_key_false(&tracepoint_printk_key.key))
> - output_printk(fbuffer);
> -
> - event_trigger_unlock_commit_regs(fbuffer->trace_file,
fbuffer->buffer,
> - fbuffer->event, fbuffer->entry,
> - fbuffer->flags, fbuffer->pc,
fbuffer->regs);
> -}
> -EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
> -
Please move the ftrace_exports routines up, instead of moving the
trace_event_buffer_commit() down. As it fits better where it is (next
to the other buffer_commit code).
-- Steve
> /*
> * Skip 3:
> *
> @@ -2868,6 +2857,19 @@ int unregister_ftrace_export(struct
> trace_export *export) }
> EXPORT_SYMBOL_GPL(unregister_ftrace_export);
>
> +void trace_event_buffer_commit(struct trace_event_buffer *fbuffer)
> +{
> + if (static_key_false(&tracepoint_printk_key.key))
> + output_printk(fbuffer);
> +
> + if (static_branch_unlikely(&ftrace_exports_enabled))
> + ftrace_exports(fbuffer->event);
I would also recommend making each static branch a separate variable.
That way you could pick and choose what you want to enable. If you only
want events, and functions are being traced, it will add a bit of
overhead to handle the functions to just ignore them.
That is:
ftrace_exports_enabled, trace_event_exports_enabled,
trace_marker_exports_enabled.
-- Steve
That's a good idea. Let me add that to next revision.
> + event_trigger_unlock_commit_regs(fbuffer->trace_file,
> fbuffer->buffer,
> + fbuffer->event, fbuffer->entry,
> + fbuffer->flags, fbuffer->pc,
> fbuffer->regs); +}
> +EXPORT_SYMBOL_GPL(trace_event_buffer_commit);
> +
> void
> trace_function(struct trace_array *tr,
> unsigned long ip, unsigned long parent_ip, unsigned
> long flags,
