Re: [Patch 7/8] Enhanced partition statistics: procfs

[Jerome Marchand <jmarchan@redhat.com>]

Randy Dunlap wrote:
> On Thu, 13 Dec 2007 18:36:45 +0100 Jerome Marchand wrote:
> 
>> Randy Dunlap wrote:
>>> The format of the /proc file is not changed except to add data
>>> at the end of each line.  Is that correct?
>>>
>> No. The line concerning partitions will display different data. The new format match the current format
>> concerning disks.
>>
>> Current partition format:
>> major minor name reads_issued sectors_read writes_issued sectors_written
>>
>> New partition format (current disk format):
>> major minor name reads_issued reads_merged sector_read ms_reading writes_completed writes_merged sectors_written ms_writing I/Os_running ms_I/O weighted_ms_I/O
> 
> 
> I would have expected the /proc file contents to represent a user
> interface that we shouldn't change, other than by adding to the end
> of each line.
> 

I could eventually keep the old data and add the new ones at the end
of the line, but it will leads to a less coherent interface. Moreover
all the users of /proc/diskstats I know about use the number of field
to make the distinction between current disk and partitions
format. They all will be confused if we add new fields.

Jérôme