Re: [PATCH] tracing: fix missing function_graph events when we splice_read from trace_pipe

[Frederic Weisbecker <fweisbec@gmail.com>]

On Tue, Jul 28, 2009 at 08:17:22PM +0800, Lai Jiangshan wrote:
> 
> About a half events are missing when we splice_read
> from trace_pipe. They are consumed unexpected.
> 
> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
> ---


Also queued for .31
Thanks!


> diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
> index e30e6b1..41996fc 100644
> --- a/kernel/trace/trace.c
> +++ b/kernel/trace/trace.c
> @@ -3085,7 +3085,8 @@ tracing_fill_pipe_page(size_t rem, struct trace_iterator *iter)
>  			break;
>  		}
>  
> -		trace_consume(iter);
> +		if (ret != TRACE_TYPE_NO_CONSUME)
> +			trace_consume(iter);
>  		rem -= count;
>  		if (!find_next_entry_inc(iter))	{
>  			rem = 0;
> @@ -4230,8 +4231,11 @@ static void __ftrace_dump(bool disable_tracing)
>  		iter.pos = -1;
>  
>  		if (find_next_entry_inc(&iter) != NULL) {
> -			print_trace_line(&iter);
> -			trace_consume(&iter);
> +			int ret;
> +
> +			ret = print_trace_line(&iter);
> +			if (ret != TRACE_TYPE_NO_CONSUME)
> +				trace_consume(&iter);
>  		}
>  
>  		trace_printk_seq(&iter.seq);
> 
>