Re: [PATCH] [RFC] emit-crash-char: Allow diversion of printk output for crash logging

["Mike Frysinger" <vapier.adi@gmail.com>]

On Fri, Aug 8, 2008 at 4:10 PM, Daniel Walker wrote:
> On Fri, 2008-08-08 at 14:09 -0400, Mike Frysinger wrote:
>> > I invite you to give some of the "plenty of
>> > examples in the tree", you might surprise me..
>>
>> look at all the new syscalls added without any userspace code in place
>> (still) to use it.  or Linus' recent printk modifier extension.  or my
>> printk extensions for extracting portions of the kernel log buffer.
>> people usually submit interfaces with backend extesions, or the intent
>> to use it is obvious.
>
> Syscalls and Userspace are unrelated .. You clearly can't add userspace
> code to the kernel .. If you add a _kernel_ interface like David has
> done you need at least one user of the interface.. Otherwise it's just
> plain bloat inside the kernel which no one wants.
>
> Your changes for extracting part of the kernel log buffer (commit
> 0b15d04af3dd996035d8fa81fc849d049171f9c3),
>
> with:
>   text    data     bss     dec     hex filename
> 4322000  386760 2592768 7301528  6f6998 vmlinux
> without:
>   text    data     bss     dec     hex filename
> 4321876  386760 2592768 7301404  6f691c vmlinux
>
> Adds roughly 120bytes of bloat to my kernel, since 2007 .. What's the
> point? I grepped for users , and there are none ..

same sort of things as the point of David's code.  early/crash
scenarios for people to safely extract portions of the kernel log
buffer for transmission/storage elsewhere.  as was explained in the
original thread behind the commit.
-mike