cfi_{build,send_gen}_cmd bloats, how to uninline?

[Ilpo Järvinen]

Hi,

When doing some time ago measurements on how static inlines affect the 
size of the kernel, I found out that uninlining cfi_{build,send_gen}_cmd 
yield to considerable size reduction (measured with 32-bit x86, gcc 
version 4.1.2 20070626 (Red Hat 4.1.2-13), on v2.6.25-rc2-mm1 IIRC, 
allyesconfig minus number of manually selected DEBUG related CONFIGs):

42 funcs, 199 +, 33328 -, diff: -33129 --- cfi_build_cmd
14 funcs, 365 +, 14648 -, diff: -14283 --- cfi_send_gen_cmd

...(Because there's depency between them as cfi_send_gen_cmd includes a 
call to cfi_build_cmd, total for both to is likely going to less than what 
those two summed together are, uninlining cfi_send_gen_cmd might even not 
pay off much).

I'm unsure how should the uninlining be performed in this case, 
especially since there's some alerting comment like this:

"/* We do it this way to give the compiler a fighting chance
    of optimising away all ..."

"* It looks too long to be inline, but in the common case it should almost all
 * get optimised away."

...Perhaps somebody has just assumed gcc to be more clever than it 
actually is, I wonder if the claimed optimization was ever happening
in practice... :-/

Any ideas?


-- 
 i.