[PATCH v1 1/1] ACPI: bus: Reduce runtime memory footprint of struct acpi_device

[PATCH v1 1/1] ACPI: bus: Reduce runtime memory footprint of struct acpi_device

[Andy Shevchenko]

The ACPI handler is heavily used by the ACPI code. Making it as
the first member in the struct acpi_device reduces code size.
For instance, the drivers/acpi/scan.o (with `make allyesconfig`)
gives this statistics:

add/remove: 0/0 grow/shrink: 3/8 up/down: 50/-169 (-119)
Function                                     old     new   delta
acpi_device_add                             2294    2319     +25
acpi_add_single_object                      6523    6544     +21
acpi_dev_get_next_consumer_dev               602     606      +4
acpi_tie_acpi_dev                            169     165      -4
acpi_scan_drop_device                        319     315      -4
acpi_dev_clear_dependencies                 1151    1147      -4
acpi_bus_attach                             2898    2894      -4
acpi_dma_get_range                          1420    1415      -5
acpi_init_device_object                     5497    5485     -12
acpi_bus_check_add                          1940    1923     -17
acpi_device_hotplug                         3407    3288    -119
Total: Before=77509, After=77390, chg -0.15%

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 include/acpi/acpi_bus.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
index a10a591c18b2..64ae66ca456e 100644
--- a/include/acpi/acpi_bus.h
+++ b/include/acpi/acpi_bus.h
@@ -435,9 +435,9 @@ struct acpi_device_software_nodes {
 
 /* Device */
 struct acpi_device {
+	acpi_handle handle;		/* no handle for fixed hardware */
 	u32 pld_crc;
 	int device_type;
-	acpi_handle handle;		/* no handle for fixed hardware */
 	struct fwnode_handle fwnode;
 	struct list_head wakeup_list;
 	struct list_head del_list;
-- 
2.50.1

Re: [PATCH v1 1/1] ACPI: bus: Reduce runtime memory footprint of struct acpi_device

[Rafael J. Wysocki (Intel)]

On Wed, Sep 9, 2026 at 6:39 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> The ACPI handler is heavily used by the ACPI code. Making it as
> the first member in the struct acpi_device reduces code size.
> For instance, the drivers/acpi/scan.o (with `make allyesconfig`)
> gives this statistics:
>
> add/remove: 0/0 grow/shrink: 3/8 up/down: 50/-169 (-119)
> Function                                     old     new   delta
> acpi_device_add                             2294    2319     +25
> acpi_add_single_object                      6523    6544     +21
> acpi_dev_get_next_consumer_dev               602     606      +4
> acpi_tie_acpi_dev                            169     165      -4
> acpi_scan_drop_device                        319     315      -4
> acpi_dev_clear_dependencies                 1151    1147      -4
> acpi_bus_attach                             2898    2894      -4
> acpi_dma_get_range                          1420    1415      -5
> acpi_init_device_object                     5497    5485     -12
> acpi_bus_check_add                          1940    1923     -17
> acpi_device_hotplug                         3407    3288    -119
> Total: Before=77509, After=77390, chg -0.15%
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
>  include/acpi/acpi_bus.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h
> index a10a591c18b2..64ae66ca456e 100644
> --- a/include/acpi/acpi_bus.h
> +++ b/include/acpi/acpi_bus.h
> @@ -435,9 +435,9 @@ struct acpi_device_software_nodes {
>
>  /* Device */
>  struct acpi_device {
> +       acpi_handle handle;             /* no handle for fixed hardware */
>         u32 pld_crc;
>         int device_type;
> -       acpi_handle handle;             /* no handle for fixed hardware */
>         struct fwnode_handle fwnode;
>         struct list_head wakeup_list;
>         struct list_head del_list;
> --

Applied as 7.4 material, thanks!