Re: [RFC PATCH 1/2] Makefile: export-symbol usage report generator.

[Adrian Bunk <bunk@stusta.de>]

On Wed, Apr 19, 2006 at 04:25:58PM -0700, Ram Pai wrote:
> On Tue, 2006-04-18 at 16:09 +0200, Adrian Bunk wrote:
> > On Thu, Apr 13, 2006 at 05:38:26AM -0700, Ram Pai wrote:
> > 
> > > I ran a report to extract export-symbol usage by kernel modules.  The results
> > > are at http://www.sudhaa.com/~ram/misc/export_report.txt
> > > 
> > > The report lists:
> > > 1. All the exported symbols and their usage counts by in-kernel modules.
> > > 2. for each in-kernel module, lists the modules and the exported symbols
> > > 	from those modules, that it depends on.
> > > 
> > > Highlights: 
> > > 	On x86 architecture
> > >  	(1) 880 exported symbols not used by any in-kernel modules.
> > >         (2) 1792 exported symbols used only once.
> > > 
> > > I hope this report/tool shall help all inkernel modules to revisit their usage
> > > of kernel interfaces.
> > > 
> > > This patch integrates the report-generator into the kernel build process. After
> > > applying this patch, invoke 'make export_report'  and it creates the report in
> > > Documentation/export_report.txt
> > >...
> > 
> > I like your patch, but I have observed two issues:
> > - please don't force an allmodconfig, simply use the currently compiled
> >   kernel 
> 
> Looking for ideas. Its hard to extract out the imported symbols unless
> they are compiled as modules. Running the report on a currently compiled
> kernel will miss most of the subsystems that are not compile as modules.
> Hence the report wont be complete.  Any suggestions?
>...

- it's a tool for kernel hackers who know what they are doing
- it's a tool to help you finding unused exports, but each one still
  requires manual verification

Besides this, e.g. CONFIG_SMP=n brings you more modules and therefore a 
better coverage than allmodconfig.

cu
Adrian

-- 

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       "Only a promise," Lao Er said.
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