Re: [PATCH] ftrace: don't increment @pos in g_start()

[Wang Liming]

Li Zefan wrote:
> Wang Liming wrote:
> > Li Zefan wrote:
> > > Li Zefan wrote:
> > > > Liming Wang wrote:
> > > > > how about this one?
> > > > Yeah, this should work, and cleaner than my version.
> > > Hmmm, the patch is cleaner in diffstat but the resulted code
> > > isn't..
> > >
> > > After yours:
> > >    text    data     bss     dec     hex filename
> > >   14879    5480    4240   24599    6017 kernel/trace/ftrace.o
> > >
> > > After mine:
> > >    text    data     bss     dec     hex filename
> > >   14873    5480    4240   24593    6011 kernel/trace/ftrace.o
> > Hmmm, if you prefer to smaller target size, I don't care.
> > But in my system, I got the same size:
> >
> >   text    data     bss     dec     hex filename
> >   14330    5019     104   19453    4bfd kernel/trace/ftrace.o
> >
> > I use objdump to compute the actual size of all modified functions:
> >
> > After mine:
> > func    size
> > g_start 0x50
> > g_next  0x70
> >
> > After yours:
> > func     size
> > __g_next 0x70
> > g_next   0x20
> > g_start  0x30
> >
> > I used Steve git tree and commit e482f8395f215e0ad6557b2722cd9b9b308035c4.
> > My gcc version is :
> > gcc version 4.2.4
> >
> > I don't know where the difference.
>
> Maybe because of different gcc versions:
>
> # gcc --version
> gcc (GCC) 4.1.2 20070925 (Red Hat 4.1.2-33)
Maybe.

> The point is, I don't see how the patch you posted is better than
> mine. And it's fine for me to pick up yours if it's indeed better.
OK, it's fine to me to pick up yours. Nothing different.
Back to your patch:

> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index ec18bb4..2c1c761 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -2492,32 +2492,30 @@ int ftrace_graph_count;
>  unsigned long ftrace_graph_funcs[FTRACE_GRAPH_MAX_FUNCS] __read_mostly;
>
>  static void *
> -g_next(struct seq_file *m, void *v, loff_t *pos)
> +__g_next(struct seq_file *m, loff_t *pos)
>  {
>  	unsigned long *array = m->private;
> -	int index = *pos;
>
> -	(*pos)++;
> +	/* Nothing, tell g_show to print all functions are enabled */
> +	if (!ftrace_graph_count && !*pos)
> +		return (void *)1;
I think this checking should be put back to g_start, because it's only necessary 
for g_start.

Liming Wang

>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/