[Crash-utility] Adding a new command rbtree

[Dave Anderson]

----- Original Message -----
> Hello Dave,
> 
> The attachment is the code that adds two command, rbtree and rdtree.  The
> commands work well, but, onsidering some code is a copy of command list,
> I think the code still need a big change.
> 

Hi Qiao,

I haven't been able to spend much time looking at this patch, but
these are my initial impressions.

My suggestion of a single "tree" command was just that, where there 
would be a single "tree" command, and that command would require an
option to make the differentiation between an red-black tree and a 
radix tree. 

I don't quite understand why you *only* have the "[-o] offset" advertised 
for the rbtree command?  Virtually every instance of a radix_tree_root
structure in the kernel is embedded in a data structure, similar to the 
typical usage of an rb_root.  Why the difference? 

The "-H start" option should probably be something like "-R" for "root".
When -H is used in the list command, it refers to list_[H]ead.

The examples in the help pages are not particularly helpful.
I don't know what "tts.rb" refers to?  Can you find better examples
that the user can relate to? 

Also, a clear explanation of what the "position information" actually
means would be helpful.

Thanks,
  Dave