Re: [3/4] [PATCH]Diskdump - yet another crash dump function

[Takao Indoh <indou.takao@soft.fujitsu.com>]

Hi,

On Mon, 21 Jun 2004 15:46:11 +1000, Keith Owens wrote:

>On Thu, 17 Jun 2004 14:13:56 +0200, 
>Ingo Molnar <mingo@elte.hu> wrote:
>>but there's another possible method (suggested by Alan Cox) that
>>requires no changes to the timer API hotpaths: 'clear' all timer lists
>>upon a crash [once all CPUs have stopped and irqs are disabled] and just
>>let the drivers use the normal timer APIs. Drive timer execution via a
>>polling method.
>>
>>this basically approximates your polling based implementation but uses
>>the existing kernel timer data structures and timer mechanism so should
>>be robust and compatible. It doesnt rely on any previous state (because
>>all currently pending timers are discarded) so it's as crash-safe as
>>possible.
>
>Don't forget live crash dumping.  The system is running and is behaving
>strangely so you want to take a dump for investigation, but you do not
>want to kill the system afterwards.  Live crash dumping is very useful
>for problem diagnosis.
>It is a little more complex than dumping after an oops because you must
>not destroy any kernel data, including timer lists.

The method he proposed is used only when die/panic happens. Live dump
is a function crash command provides throuth /dev/mem.

Best Regards,
Takao Indoh