Message-Id: <4964CA0A.76E4.0078.0@novell.com>
Date: Wed, 07 Jan 2009 14:28:10 +0000
From: "Jan Beulich" <jbeulich@novell.com>
To: "Al Viro" <viro@ZenIV.linux.org.uk>
Cc: <ccache@lists.samba.org>, "Theodore Ts'o" <tytso@mit.edu>,
       "Sam Ravnborg" <sam@ravnborg.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [REGRESSION] Recent change to kernel spikes out
	 ccache/distcc
References: <E1LKDeQ-0002xz-7E@closure.thunk.org>
 <20090107051027.GU28946@ZenIV.linux.org.uk>
 <49647A9E.76E4.0078.0@novell.com>
 <20090107140328.GV28946@ZenIV.linux.org.uk>
In-Reply-To: <20090107140328.GV28946@ZenIV.linux.org.uk>
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>>> Al Viro <viro@ZenIV.linux.org.uk> 07.01.09 15:03 >>>
>I do not understand two things.
>	a) WTF would we care about ones in vmlinux, when kallsyms drops the
>absolute ones anyway?

The patch is not only about __crc_* - for vmlinux, this part really doesn't
matter, but there's a significant amount of other symbols that get stripped
from vmlinux with the second patch.

>	b) is there any reason why we can't copy symbol table out of module
>ourselves (instead of setting SHF_ALLOC on it) and trim the crap out of
>it?  Note that __crc_... is not the only junk in there - you don't need
>(or want) to keep the things like undefs for /proc/kallsyms purposes.
>And modules *using* an exported symbol are more common that modules exporting
>one...  Why not copy it at add_kallsyms() time, skipping the junk we don't
>want anyway?

Would certainly be doable, but would seem reasonable only if it's a small
set of easily recognizable symbols. If you look at scripts/strip-symbols,
you may agree that it's better to do this at build time...

Jan

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