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Date: Sat, 25 Oct 2008 18:21:16 +0200
From: Sam Ravnborg <sam@ravnborg.org>
To: Arjan van de Ven <arjan@infradead.org>
Cc: torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
       Matt Mackall <mpm@selenic.com>
Subject: Re: [pull request] getting rid of __cpuinit
Message-ID: <20081025162116.GA13303@uranus.ravnborg.org>
References: <20081024142056.6a2d082a@infradead.org> <20081025075925.GA22805@uranus.ravnborg.org> <20081025070043.50578543@infradead.org> <20081025143528.GA30900@uranus.ravnborg.org> <20081025080638.6203c874@infradead.org>
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On Sat, Oct 25, 2008 at 08:06:38AM -0700, Arjan van de Ven wrote:
> On Sat, 25 Oct 2008 16:35:28 +0200
> Sam Ravnborg <sam@ravnborg.org> wrote:
> > So if you look at the size of the cpuinit/exit sections in the
> > before case you get the real space saving that is lost in the
> > embedded case after your patch is applied.
> > The space savings that happen after early init.
> 
> [linux.trees.git]# objdump -h vmlinux.before  | grep init.text
>  25 .init.text    00037c25  ffffffff8152a000  000000000152a000  0092a000
> [inux.trees.git]# objdump -h vmlinux.after  | grep init.text
>  25 .init.text    000316c2  ffffffff81542000  0000000001542000  00942000

So with your config we will loose a saving of 25955 bytes
of text.

I tried to look a the numbers of a defconfig build here.
cpuinit.text equals 0x5d97 = 23959
cpuinit.data equals 0x3574 = 13684

[objdump of vmlinux.o gives you the size of the cpuinit sections]

So if we decide to drop cpuinit then it should be based on the
above figure and not the 2k figure you gave in the original mail.

Or even better we should see the difference with a typical
embedded configuration and not some big defconfig build.
I will assume the saving is less on a typical embedded
configuration.

	Sam