Re: [PATCH] Re: crc32 and lib.a (was Re: [PATCH] nbd in 2.5.3 does

[Andrew Morton <akpm@zip.com.au>]

Chris Wedgwood wrote:
> 
> On Thu, Jan 31, 2002 at 11:24:10PM +0000, Alan Cox wrote:
> 
>     Because 100 4K drivers suddenly becomes 0.5Mb. There are those of
>     us trying to stuff Linux into embedded devices who if anything
>     want more configuration options not people taking stuff out.
> 
> Well, I'm more or less in agreement here, especially when working with
> small embedded devices which have a few (say 16 or 32) MB of RAM for
> EVERYTHING, kernel, userspace AND filesystems.
> 
> However, I wonder if we can't have the linker remove unnecessary and
> unreferences objects, functions and variables?

We can.  Graham Stoney had all this going against 2.2.  See

http://www.google.com/search?q=stoney+ffunction-sections&hl=en&start=10&sa=N
http://www.cs.helsinki.fi/linux/linux-kernel/Year-2000/2000-29/0415.html

>     What I'd much rather see if this is an issue is:
> 
>     bool        'Do you want to customise for a very small system'
> 
> _IF_ the linker can remove things, it would simplify this too --- we
> could if a few important places produce code slightly differently to
> favour speed over size and not reference various things.  Also, the
> above option would turn-off inlining as that seems to makie quite a
> difference at times (BTW, I'm not sure about this, but it seems gcc
> and C99 don't agree with static/extern inline semantics?)

The kernel doesn't link when you compile with -fno-inline because of all
the `extern inline' qualifiers.  These need to be converted to `static
inline'.    Jim Houston has a script which does this.  See

	http://www.uwsg.iu.edu/hypermail/linux/kernel/0201.3/0888.html

It would be rather good if we could get that script run across the
tree - no-inline has its uses at times.

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