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Groups > linux.kernel > #1681259 > unrolled thread
| Started by | Viresh Kumar <viresh.kumar@linaro.org> |
|---|---|
| First post | 2017-07-05 06:00 +0200 |
| Last post | 2017-07-05 12:20 +0200 |
| Articles | 2 — 2 participants |
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Re: [PATCH] cpufreq: speedstep: remove unnecessary static in speedstep_detect_chipset() Viresh Kumar <viresh.kumar@linaro.org> - 2017-07-05 06:00 +0200
Re: [PATCH] cpufreq: speedstep: remove unnecessary static in speedstep_detect_chipset() Dominik Brodowski <linux@dominikbrodowski.net> - 2017-07-05 12:20 +0200
| From | Viresh Kumar <viresh.kumar@linaro.org> |
|---|---|
| Date | 2017-07-05 06:00 +0200 |
| Subject | Re: [PATCH] cpufreq: speedstep: remove unnecessary static in speedstep_detect_chipset() |
| Message-ID | <tZJDP-Rz-1@gated-at.bofh.it> |
+ Dominic,
On 04-07-17, 22:09, Gustavo A. R. Silva wrote:
> Remove unnecessary static on local variable hostbridge.
> Such variable is initialized before being used,
> on every execution path throughout the function.
> The static has no benefit and, removing it reduces
> the code size.
>
> This issue was detected using Coccinelle and the following semantic patch:
>
> @bad exists@
> position p;
> identifier x;
> type T;
> @@
>
> static T x@p;
> ...
> x = <+...x...+>
>
> @@
> identifier x;
> expression e;
> type T;
> position p != bad.p;
> @@
>
> -static
> T x@p;
> ... when != x
> when strict
> ?x = e;
>
> In the following log you can see the difference in the code size. Also,
> there is a significant difference in the bss segment. This log is the
> output of the size command, before and after the code change:
>
> before:
> text data bss dec hex filename
> 5084 3392 256 8732 221c drivers/cpufreq/speedstep-ich.o
>
> after:
> text data bss dec hex filename
> 5062 3304 192 8558 216e drivers/cpufreq/speedstep-ich.o
>
> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
> ---
> drivers/cpufreq/speedstep-ich.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/speedstep-ich.c b/drivers/cpufreq/speedstep-ich.c
> index b86953a..0412a24 100644
> --- a/drivers/cpufreq/speedstep-ich.c
> +++ b/drivers/cpufreq/speedstep-ich.c
> @@ -207,7 +207,7 @@ static unsigned int speedstep_detect_chipset(void)
> * 8100 which use a pretty old revision of the 82815
> * host bridge. Abort on these systems.
> */
> - static struct pci_dev *hostbridge;
> + struct pci_dev *hostbridge;
This was added way back Sep'02 by Dominic (@Dominic: I hope you are the same
Dominic with a different email id) and I don't think we need it to be static
here. Anyway, Dominic can respond on that.
commit 1673f3b404bd ("[PATCH] CPUfreq i386 drivers update")
(Note: You can find it in history kernel git repo, not the current one).
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
--
viresh
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| From | Dominik Brodowski <linux@dominikbrodowski.net> |
|---|---|
| Date | 2017-07-05 12:20 +0200 |
| Message-ID | <tZPzz-4Wj-5@gated-at.bofh.it> |
| In reply to | #1681259 |
Viresh, Gustavo,
On Wed, Jul 05, 2017 at 09:23:44AM +0530, Viresh Kumar wrote:
> + Dominic,
>
> On 04-07-17, 22:09, Gustavo A. R. Silva wrote:
> > Remove unnecessary static on local variable hostbridge.
> > Such variable is initialized before being used,
> > on every execution path throughout the function.
> > The static has no benefit and, removing it reduces
> > the code size.
> >
> > This issue was detected using Coccinelle and the following semantic patch:
> >
> > @bad exists@
> > position p;
> > identifier x;
> > type T;
> > @@
> >
> > static T x@p;
> > ...
> > x = <+...x...+>
> >
> > @@
> > identifier x;
> > expression e;
> > type T;
> > position p != bad.p;
> > @@
> >
> > -static
> > T x@p;
> > ... when != x
> > when strict
> > ?x = e;
> >
> > In the following log you can see the difference in the code size. Also,
> > there is a significant difference in the bss segment. This log is the
> > output of the size command, before and after the code change:
> >
> > before:
> > text data bss dec hex filename
> > 5084 3392 256 8732 221c drivers/cpufreq/speedstep-ich.o
> >
> > after:
> > text data bss dec hex filename
> > 5062 3304 192 8558 216e drivers/cpufreq/speedstep-ich.o
> >
> > Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com>
> > ---
> > drivers/cpufreq/speedstep-ich.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/cpufreq/speedstep-ich.c b/drivers/cpufreq/speedstep-ich.c
> > index b86953a..0412a24 100644
> > --- a/drivers/cpufreq/speedstep-ich.c
> > +++ b/drivers/cpufreq/speedstep-ich.c
> > @@ -207,7 +207,7 @@ static unsigned int speedstep_detect_chipset(void)
> > * 8100 which use a pretty old revision of the 82815
> > * host bridge. Abort on these systems.
> > */
> > - static struct pci_dev *hostbridge;
> > + struct pci_dev *hostbridge;
>
> This was added way back Sep'02 by Dominic (@Dominic: I hope you are the same
> Dominic with a different email id) and I don't think we need it to be static
> here. Anyway, Dominic can respond on that.
>
> commit 1673f3b404bd ("[PATCH] CPUfreq i386 drivers update")
>
> (Note: You can find it in history kernel git repo, not the current one).
>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
indeed, that's me, and the patch seems to be valid and therefore is a useful
improvement:
Acked-by: Dominik Brodowski <linux@dominikbrodowski.net>
Thanks,
Dominik
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