Re: [patch] uninline init_waitqueue_*() functions

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxx> wrote:

> * Andrew Morton <akpm@xxxxxxxx> wrote:
> 
> > > > shrinks fs/select.o by eight bytes.  (More than I expected).  So 
> > > > it does appear to be a space win, but a pretty slim one.
> > > 
> > > there are 855 calls to these functions in the allyesconfig vmlinux i 
> > > did, and i measured a combined size reduction of 34791 bytes. That 
> > > averages to a 40 bytes win per call site. (on i386.)
> > > 
> > 
> > Yes, but that lumps all three together.  init_waitqueue_head() is 
> > obviously the porky one.  And it's porkier with CONFIG_DEBUG_SPINLOCK 
> > and CONFIG_LOCKDEP, which isn't the case to optimise for.
> 
> true. I redid my tests with both lockdep and debug-spinlocks turned off:
> 
>   text            data    bss     dec             filename
>   21172153        6077270 3081864 30331287        vmlinux.x32.after
>   21198222        6077106 3081864 30357192        vmlinux.x32.before
> 
> with 851 callsites that's a 30.6 bytes win per call site (total 26K) - 
> still not bad at all.

and that was with CONFIG_CC_OPTIMIZE_FOR_SIZE enabled. With 
optimize-for-size disabled the win goes up to 32.6 bytes (total 28K).

	Ingo
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