Cc: Ingo Molnar <mingo@...>, Peter Zijlstra <a.p.zijlstra@...>, <linux-kernel@...>, Andrew Morton <akpm@...>, Linus Torvalds <torvalds@...>, Sam Ravnborg <sam@...>, Alexander Viro <viro@...>, H. Peter Anvin <hpa@...>
On Tue, May 06, 2008 at 02:21:31AM +0200, Andi Kleen wrote:
It's a common case that a function has only one caller. It should always
be an (at least tiny) space win to get them inlined.
I'm not attaching size change information to these patches since
whatever change one sees anyway also depends on other factors like
the exact kernel configuration, so it's non-trivial to get numbers
that could be taken seriously.
There are many small aspects, e.g. both gcc with -Wmissing-prototypes
and sparse give warnings, and the problem might either be needlessly
global code or the fact that a function prototype is either not in a
header or the header not #include'd by the file. Although I've only
2 or 3 times catched such bugs in the kernel that is a nasty to debug
class of bugs and gcc can find such problems at compile time.
The best case I've actually seen in practice was a variable I made
static, and with CONFIG_DEBUG_FOOBAR=n gcc was now able to prove that
the value never changed resulting in the variable plus quite a chunk
of code no longer emitted.
cu
Adrian
--
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed
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