Date: Thu, 28 Sep 2006 09:18:09 -0700
From: Andrew Morton <akpm@osdl.org>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Andi Kleen <ak@muc.de>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Put the BUG __FILE__ and __LINE__ info out of line
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On Thu, 28 Sep 2006 03:27:12 -0700
Jeremy Fitzhardinge <jeremy@goop.org> wrote:

> Andrew Morton wrote:
> > Plan #17 is to just put the BUG inline and then put the EIP+file*+line into
> > a separate section, then search that section at BUG time to find the record
> > whose EIP points back at this ud2a.
> >   
> 
> Sure, but it seems a bit complex for this; I think simpler is better 
> when the kernel has got itself into an iffy state.

It's just a linear search.

> > It's a bit messy for modules, but it minimises the .text impact and keeps
> > disassembly happy, no?
> >   
> I'm not quite sure I understand your concern.  You're worried about the 
> size increase to vmlinux in the case where you specify 
> CONFIG_DEBUG_BUGVERBOSE?

- We're using ten bytes of instruction cache where we could use two bytes

- If this is done right, other architectures can use the look-it-up code,
  thus cleaning up the kernel codebase.

And looky, powerpc already does this, so it'd be a matter of librarifying
their code.

-
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