[1/2] PCI: Reorder some fields in 'struct pci_dev'

Message ID 407b17c3e56764ef2c558898d4ff4c6c04b2d757.1687105455.git.christophe.jaillet@wanadoo.fr
State New
Headers
Series [1/2] PCI: Reorder some fields in 'struct pci_dev' |

Commit Message

Christophe JAILLET June 18, 2023, 4:24 p.m. UTC
  Group some bitfield variables to reduce hole.
On x86_64, this shrinks the size of 'struct pci_dev' by 16 bytes when
compiled with 'allmodconfig'. This goes from 3576 to 3560.

The move related to CONFIG_PCIEASPM depends on the config. But it gives
the opportunity to merge to bitfields.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 include/linux/pci.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
  

Comments

Bjorn Helgaas July 13, 2023, 4:24 p.m. UTC | #1
On Sun, Jun 18, 2023 at 06:24:54PM +0200, Christophe JAILLET wrote:
> Group some bitfield variables to reduce hole.
> On x86_64, this shrinks the size of 'struct pci_dev' by 16 bytes when
> compiled with 'allmodconfig'. This goes from 3576 to 3560.
> 
> The move related to CONFIG_PCIEASPM depends on the config. But it gives
> the opportunity to merge to bitfields.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

Both patches applies to pci/misc for v6.6, thanks!

> ---
>  include/linux/pci.h | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/linux/pci.h b/include/linux/pci.h
> index c69a2cc1f412..106754757279 100644
> --- a/include/linux/pci.h
> +++ b/include/linux/pci.h
> @@ -366,8 +366,8 @@ struct pci_dev {
>  	pci_power_t	current_state;	/* Current operating state. In ACPI,
>  					   this is D0-D3, D0 being fully
>  					   functional, and D3 being off. */
> -	unsigned int	imm_ready:1;	/* Supports Immediate Readiness */
>  	u8		pm_cap;		/* PM capability offset */
> +	unsigned int	imm_ready:1;	/* Supports Immediate Readiness */
>  	unsigned int	pme_support:5;	/* Bitmask of states from which PME#
>  					   can be generated */
>  	unsigned int	pme_poll:1;	/* Poll device's PME status bit */
> @@ -392,9 +392,9 @@ struct pci_dev {
>  
>  #ifdef CONFIG_PCIEASPM
>  	struct pcie_link_state	*link_state;	/* ASPM link state */
> +	u16		l1ss;		/* L1SS Capability pointer */
>  	unsigned int	ltr_path:1;	/* Latency Tolerance Reporting
>  					   supported from root to here */
> -	u16		l1ss;		/* L1SS Capability pointer */
>  #endif
>  	unsigned int	pasid_no_tlp:1;		/* PASID works without TLP Prefix */
>  	unsigned int	eetlp_prefix_path:1;	/* End-to-End TLP Prefix */
> -- 
> 2.34.1
>
  

Patch

diff --git a/include/linux/pci.h b/include/linux/pci.h
index c69a2cc1f412..106754757279 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -366,8 +366,8 @@  struct pci_dev {
 	pci_power_t	current_state;	/* Current operating state. In ACPI,
 					   this is D0-D3, D0 being fully
 					   functional, and D3 being off. */
-	unsigned int	imm_ready:1;	/* Supports Immediate Readiness */
 	u8		pm_cap;		/* PM capability offset */
+	unsigned int	imm_ready:1;	/* Supports Immediate Readiness */
 	unsigned int	pme_support:5;	/* Bitmask of states from which PME#
 					   can be generated */
 	unsigned int	pme_poll:1;	/* Poll device's PME status bit */
@@ -392,9 +392,9 @@  struct pci_dev {
 
 #ifdef CONFIG_PCIEASPM
 	struct pcie_link_state	*link_state;	/* ASPM link state */
+	u16		l1ss;		/* L1SS Capability pointer */
 	unsigned int	ltr_path:1;	/* Latency Tolerance Reporting
 					   supported from root to here */
-	u16		l1ss;		/* L1SS Capability pointer */
 #endif
 	unsigned int	pasid_no_tlp:1;		/* PASID works without TLP Prefix */
 	unsigned int	eetlp_prefix_path:1;	/* End-to-End TLP Prefix */