Re: [PATCH] optimize dmapi event tests w/o dmapi config

[Vlad Apostolov <vapo@sgi.com>]

Eric Sandeen wrote:
> Defining XFS_DM_EVENT* macros to 0 in the absence of 
> CONFIG_XFS_DMAPI allows gcc to optimize away tests that 
> should never be true. Also wrap one hunk of xfs_unmount 
> in #ifdef CONFIG_XFS_DMAPI
>   
Good idea Eric. A few remarks and a question below.
>  
> +#ifdef CONFIG_XFS_DMAPI
>   
CONFIG_XFS_DMAPI is only defined when the DMAPI is statically linked
to the kernel. When DMAPI is configured as a module,  
CONFIG_XFS_DMAPI_MODULE
is defined. The HAVE_DMAPI is defined for both, static and module DMAPI
configurations.
>  /* Defines for determining if an event message should be sent. */
>  #define	DM_EVENT_ENABLED(vfsp, ip, event) ( \
>  	unlikely ((vfsp)->vfs_flag & VFS_DMI) && \
> @@ -78,6 +79,11 @@ typedef enum {
>  		( ((io)->io_dmevmask & (1 << event)) || \
>  		  ((io)->io_mount->m_dmevmask & (1 << event)) ) \
>  	)
> +#else
> +#define DM_EVENT_ENABLED(vfsp, ip, event) (0)
>   
The above should use the new two arguments DM_EVENT_ENABLED macro.
> +#define DM_EVENT_ENABLED_IO(vfsp, io, event) (0)
>   
What is this DM_EVENT_ENABLE_IO macro for?

>  
> +#ifdef CONFIG_XFS_DMAPI

The same, use HAVE_DMAPI instead of CONFIG_XFS_DMAPI.

Otherwise it is looking good.

Regards,
Vlad