KDB enhancements

[Keith Owens]

On Fri, 18 Jul 2003 19:40:37 -0500, 
linas at austin.ibm.com wrote:
>I'm vaguely daydreaming about a few KDB enhancements, I was curious if 
>you've thought about them:
>
>-- 'cat /proc/meminfo'  Turns out one bug I was chasing was OOM on
>   a machine with 32GB of RAM (!) and it took me days to even think
>   of looking there.

'sr m', same as sysrq-m.

>-- Support for examining structures symbolically.  I've had to walk
>   the buffer cache by hand in the past, I've walked task struct
>   by hand yesterday, and they guy down the hall stares at network
>   structs.  
>
>   I don't know if it would be better to handle a few of these as 
>   special-cases in some simple manner, or if some more complex but
>   generic mechanism would be better ... 

I have considered a generic facility like gdb, based off stabs or dwarf
but decided against it for now.  Apart from the complexity of the code,
the stabds/dwarf approach is no good for bit fields.

kdb has various commands for dumping structures including vm data, see
all the code in kdb/modules.  Recent versions of kdb added a 'task'
command for dumping and decoding struct task.  Another good reason to
upate ppc64 to kdb v4.3 :).