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

Message ID 20240118152213.2644269-7-hugo@hugovil.com
State New
Headers show
Series serial: max310x: cleanups and improvements | expand

Commit Message

Hugo Villeneuve Jan. 18, 2024, 3:22 p.m. UTC 
From: Hugo Villeneuve <hvilleneuve@dimonoff.com>

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

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 {