[Crash-utility] question on some command params

[Jun Koi]

On Tue, Sep 30, 2008 at 10:47 PM, Dave Anderson <anderson at redhat.com> wrote:
> Dave Anderson wrote:
>>
>> Jun Koi wrote:
>>
>>> On Tue, Sep 23, 2008 at 12:49 AM, Dave Anderson <anderson at redhat.com>
>>> wrote:
>>>
>>>> Jun Koi wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> I found below cmdline params having no documentation anywhere, so
>>>>> could somebody explain their meaning?
>>>>>
>>>>> - memory_module
>>>>> - no_modules
>>>>> - no_ikconfig
>>>>> - no_namelist_gzip
>>>>> - no_kmem_cache
>>>>> - kmem_cache_delay
>>>>> - readnow
>>>>> - buildinfo
>>>>> - zero_excluded
>>>>>
>>>>>
>>>>> Many thanks,
>>>>> J
>>>>
>>>>
>>>> They're all essentially debug flags for use on kernels/dumpfiles
>>>> that for some reason or other would not initialize properly.
>>>>
>>>> memory_module: if /dev/mem or /dev/crash do not suffice you could
>>>> force-feed one or the other for live system analysys.
>>>
>>>
>>>
>>> Another question: Why do we need the "memory_device" param if we
>>> already had "memory_module"? Arent they the same thing? The naming
>>> here is so confused to me.
>>
>>
>> No.
>>
>> pc->memory_module is the truncated name of a loadable module, if
>> one is necessary, consisting of the module object file name minus
>> the ".o" or ".ko", whichever is applicable.  /dev/mem does not
>> require a pre-installed kernel module, whereas /dev/crash requires
>> the crash.o or crash.ko misc driver to be installed.  So if by
>> chance you want to use your own hand-rolled memory device, it may
>> or may not require that a kernel module be installed.  If it does,
>> then you would put "--memory_module your-memory-module.ko" on the
>> command line.
>>
>> pc->memory_device is the name of a device file, i.e., "/dev/mem"
>> or "/dev/crash".  It is initialized to "/dev/crash" in hopes that
>> it exists, and defaults to "/dev/mem" if it doesn't.  But again,
>> if you have your own memory device you'd like to use, you can override
>> both of them by putting "--memory_module /dev/whatever" on the command
>
> Sorry, I meant "--memory_device /dev/whatever" above...
>

Great, it is clear to me now!

I have another question: what is the purpose of the "-L" option?

Thanks,
Jun