Re: [dm-devel] REQUEST for new 'topology' metrics to be moved out of the 'queue' sysfs directory.

[Boaz Harrosh <bharrosh@panasas.com>]

On 06/29/2009 02:41 PM, Jens Axboe wrote:
> On Mon, Jun 29 2009, NeilBrown wrote:
>> On Mon, June 29, 2009 8:18 pm, Jens Axboe wrote:
>>> On Sat, Jun 27 2009, Neil Brown wrote:
>>>>> There's no such thing as first or second class block devices. The fact
>>>>> that drivers using ->make_request_fn directly do not utilize the full
>>>>> scope of the queue isn't a very interesting fact, imho.
>>>>  Your phrase "drivers using ->make_request_fn directly" seems to
>>>>  suggest you are looking at things very differently to me.
>>>>
>>>>  From my perspective, all drivers use ->make_request_fn equally.
>>>>  Some set it to "__make_request", some to "md_make_request", others to
>>>>  "dm_request" or "loop_make_request" etc.
>>> Neil, will you please stop these silly games. Stop trying to invent
>>> differences based on interpretations of what you read into my replies.
>>
>> We do seem to be having trouble communicating don't we :-(
>> Be assured that it is not my intention to play games, silly or otherwise.
>>
>> Maybe I should just try sending you patches.  Maybe that will
>> make my meaning clearer.
>>
>> For the moment, I'm much more interested in the other question,
>> that of whether I can avoid having a 'queue' directory introduced into
>> md/dm/etc device directories in sysfs.
> 
> We already talked about this, several times. My answer is that it seems
> pointless to begin with internally, and externally it just makes the API
> worse since tools then have to know which device type they are talking
> to.
> 

I do however see a problem with sysfs-files that mostly work for most devices
but for some "device type" they do nothing silently. At least make these
directory/files read-only for the un-used cases (eg. dm/md). And return proper
values to indicate their un-usefulness like "-1" or "NA"

> So I still see absolutely zero point in making such a change, quite the
> opposite.
> 

Just my $0.017
Boaz