* Re: [PATCH 1/2] ext2: Reduce object size when !CONFIG_PRINTK
[not found] ` <20130621165049.GP13932@quack.suse.cz>
@ 2013-06-21 17:06 ` Joe Perches
0 siblings, 0 replies; only message in thread
From: Joe Perches @ 2013-06-21 17:06 UTC (permalink / raw)
To: Jan Kara
Cc: linux-ext4, Theodore Ts'o, linux-kernel, linux-embedded,
openwrt-hackers
On Fri, 2013-06-21 at 18:50 +0200, Jan Kara wrote:
> On Tue 18-06-13 10:14:39, Joe Perches wrote:
> > Reducing the object size ~5kb/15% could be useful for embedded
> > systems.
> >
> > Add #ifdef CONFIG_PRINTK #else #endif blocks
> > to hold formats and arguments, passing " " to
> > functions when !CONFIG_PRINTK and still verifying
> > format and arguments with no_printk.
> >
> > $ size fs/ext2/built-in.o*
> > text data bss dec hex filename
> > 31297 44 4 31345 7a71 fs/ext2/built-in.o.ext2.new
> > 36288 44 4 36336 8df0 fs/ext2/built-in.o.ext2.old
> >
> > $ grep -E "CONFIG_EXT2|CONFIG_PRINTK" .config
> > # CONFIG_PRINTK is not set
> > CONFIG_EXT2_FS=y
> > # CONFIG_EXT2_FS_XATTR is not set
> > # CONFIG_EXT2_FS_XIP is not set
> I'm somewhat reluctant to merge this unless I know someone really
> cares. It looks a bit ugly to ifdef every function doing some printing just
> to reduce object size when CONFIG_PRINTK is disabled... And in future LTO
> might help us ;)
(adding cc's to linux-embedded and openwrt
maybe someone there cares)
Link time optimization might help some, but these calls
are still made and the strings could not be eliminated
without this.
Original patch: http://patchwork.kernel.org/patch/2744401/
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