[PATCH v2 06/17] serial: max310x: remove holes in struct max310x_devtype

From: Hugo Villeneuve
Date: Thu Jan 18 2024 - 10:23:56 EST


From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>

Running pahole shows that there are some holes within the
max310x_devtype structure.

Remove holes and optimize alignment by reorganizing structure members.

This can also lead to data structure size reduction for some CPUs.

On 64-bit CPU (arm64):
Before:
/* size: 40, cachelines: 1, members: 6 */
/* sum members: 34, holes: 2, sum holes: 6 */
/* last cacheline: 40 bytes */
After:
/* size: 40, cachelines: 1, members: 6 */
/* padding: 6 */
/* last cacheline: 40 bytes */

On 32-bit CPU (i386):
Before:
/* size: 32, cachelines: 1, members: 6 */
/* sum members: 26, holes: 2, sum holes: 6 */
/* last cacheline: 32 bytes */
After:
/* size: 24, cachelines: 1, members: 8 */
/* padding: 2 */
/* last cacheline: 24 bytes */

Suggested-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
---
drivers/tty/serial/max310x.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/max310x.c b/drivers/tty/serial/max310x.c
index 27c8ec956691..21f2fa3a91e5 100644
--- a/drivers/tty/serial/max310x.c
+++ b/drivers/tty/serial/max310x.c
@@ -258,11 +258,11 @@ struct max310x_devtype {
unsigned short min;
unsigned short max;
} slave_addr;
- char name[9];
int nr;
- u8 mode1;
int (*detect)(struct device *);
void (*power)(struct uart_port *, int);
+ char name[9];
+ u8 mode1;
};

struct max310x_one {
--
2.39.2