2018-04-05 12:01:44

by Colin King

Subject: [PATCH] gpio: 104-dio-48e: make array 'ports' static, shrinks object size

From: Colin Ian King <[email protected]>

Don't populate the const read-only array 'ports' on the stack but instead
make it static. Makes the object code smaller by over 100 buytes:

Before:
text data bss dec hex filename
10959 4952 832 16743 4167 drivers/gpio/gpio-104-dio-48e.o

After:
text data bss dec hex filename
10790 5008 832 16630 40f6 drivers/gpio/gpio-104-dio-48e.o

(gcc version 7.2.0 x86_64)

Signed-off-by: Colin Ian King <[email protected]>
---
drivers/gpio/gpio-104-dio-48e.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c
index 31e22c93e844..9c4e07fcb74b 100644
--- a/drivers/gpio/gpio-104-dio-48e.c
+++ b/drivers/gpio/gpio-104-dio-48e.c
@@ -188,7 +188,7 @@ static int dio48e_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
{
struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
size_t i;
- const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
+ static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
const unsigned int gpio_reg_size = 8;
unsigned int bits_offset;
size_t word_index;
--
2.15.1

2018-04-05 12:20:36

by William Breathitt Gray

Subject: Re: [PATCH] gpio: 104-dio-48e: make array 'ports' static, shrinks object size

On Thu, Apr 05, 2018 at 01:00:12PM +0100, Colin King wrote:
>From: Colin Ian King <[email protected]>
>
>Don't populate the const read-only array 'ports' on the stack but instead
>make it static. Makes the object code smaller by over 100 buytes:
>
>Before:
> text data bss dec hex filename
> 10959 4952 832 16743 4167 drivers/gpio/gpio-104-dio-48e.o
>
>After:
> text data bss dec hex filename
> 10790 5008 832 16630 40f6 drivers/gpio/gpio-104-dio-48e.o
>
>(gcc version 7.2.0 x86_64)
>
>Signed-off-by: Colin Ian King <[email protected]>
>---
> drivers/gpio/gpio-104-dio-48e.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c
>index 31e22c93e844..9c4e07fcb74b 100644
>--- a/drivers/gpio/gpio-104-dio-48e.c
>+++ b/drivers/gpio/gpio-104-dio-48e.c
>@@ -188,7 +188,7 @@ static int dio48e_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask,
> {
> struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip);
> size_t i;
>- const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
>+ static const size_t ports[] = { 0, 1, 2, 4, 5, 6 };
> const unsigned int gpio_reg_size = 8;
> unsigned int bits_offset;
> size_t word_index;
>--
>2.15.1
>

If this makes gpio-104-dio-48e.o smaller, then it may be worthwhile to
apply similar changes to gpio-104-idi-48.c and gpio-gpio-mm.c which have
similar get_multiple callback implementations.

Acked-by: William Breathitt Gray <[email protected]>

2018-04-26 09:07:48

by Linus Walleij

Subject: Re: [PATCH] gpio: 104-dio-48e: make array 'ports' static, shrinks object size

On Thu, Apr 5, 2018 at 2:00 PM, Colin King <[email protected]> wrote:

> From: Colin Ian King <[email protected]>
>
> Don't populate the const read-only array 'ports' on the stack but instead
> make it static. Makes the object code smaller by over 100 buytes:
>
> Before:
> text data bss dec hex filename
> 10959 4952 832 16743 4167 drivers/gpio/gpio-104-dio-48e.o
>
> After:
> text data bss dec hex filename
> 10790 5008 832 16630 40f6 drivers/gpio/gpio-104-dio-48e.o
>
> (gcc version 7.2.0 x86_64)
>
> Signed-off-by: Colin Ian King <[email protected]>

Patch applied with William's ACK.

Yours,
Linus Walleij

2018-04-26 13:04:51

by William Breathitt Gray

Subject: Re: [PATCH] gpio: 104-dio-48e: make array 'ports' static, shrinks object size

On Thu, Apr 26, 2018 at 11:06:05AM +0200, Linus Walleij wrote:
>On Thu, Apr 5, 2018 at 2:00 PM, Colin King <[email protected]> wrote:
>
>> From: Colin Ian King <[email protected]>
>>
>> Don't populate the const read-only array 'ports' on the stack but instead
>> make it static. Makes the object code smaller by over 100 buytes:
>>
>> Before:
>> text data bss dec hex filename
>> 10959 4952 832 16743 4167 drivers/gpio/gpio-104-dio-48e.o
>>
>> After:
>> text data bss dec hex filename
>> 10790 5008 832 16630 40f6 drivers/gpio/gpio-104-dio-48e.o
>>
>> (gcc version 7.2.0 x86_64)
>>
>> Signed-off-by: Colin Ian King <[email protected]>
>
>Patch applied with William's ACK.
>
>Yours,
>Linus Walleij

Hi Linus,

A more recent version of this patch including similar changes to
gpio-gpio-mm.c and gpio-104-idi-48.c is located here:
https://lkml.org/lkml/2018/4/18/613

William Breathitt Gray