Re: [RFC 0/6] Backing Store for sysfs

Nick Piggin
2003-10-07T05:26:50Z

Maneesh Soni wrote:

>On Mon, Oct 06, 2003 at 01:29:20PM -0700, Patrick Mochel wrote:
>
>>Uh, that's about the same thing I suggested, though probably not as
>>concisely:
>>
>>"As I said before, I don't know the right solution, but the directions to
>>look in are related to attribute groups. Attributes definitely consume the
>>most amount of memory (as opposed to the kobject hierachy), so delaying
>>their creation would help, hopefully without making the interface too
>>awkward.
>>
>
>Ok.. attributes do consume maximum in sysfs. In the system I mentioned
>leaf dentries are about 65% of the total.
>
>
>>You can also use the assumption that an attribute group exists for all the
>>kobjects in a kset, and that a kobject knows what kset it belongs to. And
>>
>
>That's not correct... kobject corresponding to /sys/block/hda/queue
>doesnot know which kset it belongs to and what are its attributes. Same
>for /sys/block/hda/queue/iosched.
>
>
>>that eventually, all attributes should be added as part of an attribute
>>group.."
>>
>>Attributes are the leaf entries, and they don't need to always exist. But,
>>you have easy access to them via the attribute groups of the ksets the
>>kobjects belong to.
>>
>>
>
>Having backing store just for leaf dentries should be fine. But there is
>_no_ easy access for attributes. For this also I see some data change required
>as of now. The reasons are
> - not all kobjects belong to a kset. For example, /sys/block/hda/queue
> - not all ksets have attribute groups
>
>

queue and iosched might not be good examples as they are somewhat broken
wrt the block device scheme. Possibly they will be put in their own kset,
with /sys/block/hda/queue symlinked to them.