On Wed, 2015-08-26 at 15:27 -0300, Henrique de Moraes Holschuh wrote:
> On Wed, Aug 26, 2015, at 15:13, Joe Perches wrote:
> > vdbg_printk when not using CONFIG_THINKPAD_ACPI_DEBUG uses
> > no_printk which produces no logging output but always
> > evaluates arguments.
> >
> > Change the macro to surround the no_printk call with
> > do { if (0) no_printk(...); } while (0)
> > to avoid the unnecessary argument evaluations.
> >
> > $ size drivers/platform/x86/thinkpad_acpi.o*
> > text data bss dec hex filename
> > 60918 6184 824 67926 10956
> > drivers/platform/x86/thinkpad_acpi.o.new
> > 60927 6184 824 67935 1095f
> > drivers/platform/x86/thinkpad_acpi.o.old
>
> The code size savings of this change are really small...
yup. This is just an on-the-way patch to get
all the no_printk uses in a state that can
be converted more simply to a side-effect free
mechanism.
> > --- a/drivers/platform/x86/thinkpad_acpi.c
> > +++ b/drivers/platform/x86/thinkpad_acpi.c
> > @@ -402,7 +402,7 @@ static const char *str_supported(int is_supported);
> > #else
> > static inline const char *str_supported(int is_supported) { return ""; }
> > #define vdbg_printk(a_dbg_level, format, arg...) \
> > - no_printk(format, ##arg)
> > + do { if (0) no_printk(format, ##arg); } while (0)
> > #endif
>
> And won't this change disable compile-time checking of 'format ## arg'
> for issues?
No. The call is still there so the compiler checks
the format/argument matches, but eliminates the
call and any side-effect calls from the object file.
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