[PATCH v3] makedumpfile: fix max_mapnr issue on system has over 44-bit addressing

[HATAYAMA Daisuke]

(2013/10/15 16:55), Jingbai Ma wrote:
> On 10/15/2013 01:58 PM, HATAYAMA Daisuke wrote:
>> (2013/10/14 21:16), Jingbai Ma wrote:
>> <cut>
>>> @@ -125,7 +126,7 @@ get_max_mapnr(void)
>>> unsigned long long max_paddr;
>>>
>>> if (info->flag_refiltering) {
>>> - info->max_mapnr = info->dh_memory->max_mapnr;
>>> + info->max_mapnr = info->kh_memory->max_mapnr_64;
>>> return TRUE;
>>> }
>>>
>>
>> Please:
>>
>> if (dh.header_version < 6)
>> info->max_mapnr = info->dh_memmory->max_mapnr;
>> else
>> info->max_mapnr = info->kh_memory->max_mapnr_64;
>
> If we deal the max_mapnr_64 as below I did, we do not have to check header_version everywhere when we need to the value max_mapnr. I just set it to max_mapnr_64 regardless it's old version or new in the first place we get it. It can simplify the code logic in all code. Or we have to add this version check, it's also error prone.
>

No, it complicates code logic in the sense that header on the memory and
header on the disk are not identical.

It seems to me that the case where checking header version is definitely
necessary is only when assigning either of max_mapnr values to info->max_mapnr,
after which, it's enough to refer to info->max_mapnr.

>>
>>> @@ -783,6 +784,10 @@ get_kdump_compressed_header_info(char *filename)
>>> ERRMSG("header does not have dump_level member\n");
>>> return FALSE;
>>> }
>>> +
>>> + if (dh.header_version < 6)
>>> + kh.max_mapnr_64 = dh.max_mapnr;
>>> +
>>
>> Again, please don't do this. It's confusing if in-memory header data
>> is not identical to in-disk one.
>>
>
> I have explained the reason why I set the kh.max_mapnr_64 for old version here.
> If you still think we shouldn't change this value, and should check header_version everywhere when need max_mapnr, I will send a new version to change it.
>
>


-- 
Thanks.
HATAYAMA, Daisuke