[Crash-utility] handling missing kdump pages in diskdump format

[Ken'ichi Ohmichi]

Hi Dave,

2007/04/02 08:54:38 -0400, Dave Anderson <anderson at redhat.com> wrote:
>> I think it is good that the crash utility can know the dump_level
>> of a dumpfile. But it is not good that dump_level is merged into
>> diskdump->header_version, because one member should represent one
>> meaning. I checked the code of crash-4.0-3.21, and I noticed
>> diskdump->total_ram_blocks is not referred by the crash utility
>> though the diskdump module sets the value into it. And makedumpfile
>> sets 0 into it. It does not have any meaning.
>>
>> Can this member be changed for dump_level ?
>> I think the following methods for it:
>>   - If the crash utility reads a dumpfile, it checks diskdump->
>>     header_version.
>>   - If diskdump->header_version is 1 or more, the crash utility
>>     considers diskdump->total_ram_blocks as dump_level.
>>
>> By the way, the dump_level of diskdump is different from the one
>> of kdump (makedumpfile). If the crash utility will be able to
>> display the excluded page-type, we should note it.
>>
>> The dump_level of diskdump
>>   1: Excluding cache pages with private pages
>>   2: Excluding zero-filled pages
>>   4: Excluding free pages
>>   8: Excluding user process data pages
>>  16: Saving private pages
>>
>> The dump_level of kdump (makedumpfile)
>>   1: Excluding zero-filled pages
>>   2: Excluding cache pages without private pages
>>   4: Excluding cache pages with private pages
>>   8: Excluding user process data pages
>>  16: Excluding free pages
>>
>> Thanks
>> Ken'ichi Ohmichi
>
>Sounds good to me.  I don't have any plans for the translation
>of the dump_level, but only a display of its value in a new "help -n"
>function that I've written for diskdump dumpfiles.  "help -n" shows
>netdump, ELF-diskdump, kdump, LKCD and xendump dumpfile
>information, but functions for diskdump and s390 dumps were
>never written.

It is a good idea that "help -n" shows dump_level.

I checked the code of diskdumputils-1.3.25, and I found the dumpfilter
command refers to diskdump->total_ram_blocks. In struct disk_dump_header,
there is no member not referred to by neither the crash utility or diskdumputils.
My proposal (changing total_ram_blocks for dump_level) was not good.

I think it is enough that the member for dump_level is added into the
sub header of kdump (struct kdump_sub_header) only for kdump.
Is the change for diskdump necessary, too ?


Thanks
Ken'ichi Ohmichi