Re: [patch 1/17] Infrastructure to mark exported symbols as unused-for-removal-soon

["Randy.Dunlap" <rdunlap@xenotime.net>]

On Tue, 02 May 2006 16:53:07 +0200 Arjan van de Ven wrote:

> Hi,
> As discussed on lkml before; the patch with the infrastructure to deprecate unused symbols
> 
> This is patch one in a series of 17; to not overload lkml the other 16 will be mailed direct;
> people who want to see them all can see them at http://www.fenrus.org/unused
> 
> 
> 
> This patch temporarily adds EXPORT_UNUSED_SYMBOL and EXPORT_UNUSED_SYMBOL_GPL.
> These will be used as transition measure for symbols that aren't used in the 
> kernel and are on the way out. When a module uses such a symbol, a warning
> is printk'd at modprobe time.
> 
> The main reason for removing unused exports is size: eacho export takes roughly
> between 100 and 150 bytes of kernel space in the binary. This patch gives
> users the option to immediately get this size gain via a config option.

Do the exports take any space at runtime in RAM?
or is this only on-disk or wherever the kernel image lives?


> It would be nice to at least get this infrastructure into 2.6.17 even if
> the rest of this series won't get there.

> --- linux-2.6.17-rc3-mm1-unused.orig/Documentation/feature-removal-schedule.txt
> +++ linux-2.6.17-rc3-mm1-unused/Documentation/feature-removal-schedule.txt
> @@ -22,6 +22,16 @@ Who:	Adrian Bunk <bunk@stusta.de>
>  
>  ---------------------------
>  
> +What:	Unused EXPORT_SYMBOL/EXPORT_SYMBOL_GPL exports
> +	(temporary transition config option provided until then)
> +	The transition config option will also be removed at the same time.
> +When:	before 2.6.19
> +Why:	Unused symbols are both increasing the size of the kernel binary
> +	and are often a sign of "wrong API"
> +Who:	Arjan van de Ven <arjan@linux.intel.com>


scsi patch comments (only one that I have seen) say:
+EXPORT_UNUSED_SYMBOL(scsi_print_status); /* removal in 2.6.19 */

and When: above says "before 2.6.19".  Those don't agree.
Please fix.  Thanks.

---
~Randy