Re: [LTP] [PATCH v4 4/4] zram/zram01.sh: Use mem_used_total field instead of compr_data_size field

["xuyang2018.jy@fujitsu.com" <xuyang2018.jy@fujitsu.com>]

Hi Petr
> Hi,
>
> [ Cc Martin ]
>
>> Before ltp commit 4372f7a2156 ("Fix compression ratio calculation in zram01")[1], we
>> used free -m changes to calculate the compression ratio.
>
>> After the above patch, we used compr_data_size to calculate. kernel documentation[2] has
>> the following info:
>> orig_data_size: uncompressed size of data stored in this disk.
>> compr_data_size: compressed size of data stored in this disk
>> mem_used_total: the amount of memory allocated for this disk
>
>> We should calculate the compression ratio by used disk size divided into used mem size.
>> It can also avoid the situation that division by 0 as below:
>> zram01 7 TINFO: filling zram4 (it can take long time)
>> zram01 7 TPASS: zram4 was filled with '25568' KB
>> zram01 7 TINFO: compr_size 0
>>   /opt/ltp/testcases/bin/zram01.sh: line 131: 100 * 1024 * 25568 / 0: division by 0 (error token is "0")
>
> Thank you for addressing this issue. replacing "data *stored* in this disk" with
> "*allocated* for this disk" could help (although looking at kernel code
> mm_stat_show(), I would not be sure).
Sound reasonable.

Will send a v5 next week and wait some time to listen more advise from 
others for this patchset.

Best Regards
Yang Xu
>
> Reviewed-by: Petr Vorel<pvorel@suse.cz>
>
> Kind regards,
> Petr

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