Re: [Qemu-devel] [PATCH v3 5/7] block: add throttle block filter driver

[Alberto Garcia]

On Wed 09 Aug 2017 11:36:12 AM CEST, Manos Pitsidianakis wrote:
> On Tue, Aug 08, 2017 at 05:04:48PM +0200, Alberto Garcia wrote:
>>On Tue 08 Aug 2017 04:56:20 PM CEST, Manos Pitsidianakis wrote:
>>>>> So basically if we have anonymous groups, we accept limits in the
>>>>> driver options but only without a group-name.
>>>>
>>>>In the commit message you do however have limits and a group name, is
>>>>that a mistake?
>>>>
>>>>    -drive driver=throttle,file.filename=foo.qcow2, \
>>>>           limits.iops-total=...,throttle-group=bar
>>>
>>> Sorry this wasn't clear, I'm actually proposing to remove limits from
>>> the throttle driver options and only create/config throttle groups via
>>> -object/object-add.
>>
>>Sorry I think it was me who misunderstood :-) Anyway in the new
>>command-line API I would be more inclined to have limits defined using
>>"-object throttle-group" and -drive would only reference the group id.
>>
>>I understand that this implies that it wouldn't be possible to create
>>anonymous groups (at least not from the command line), is that a
>>problem?
>
> We can accept anonymous groups if a user specifies limits but not a
> group name in the throttle driver. (The only case where limits would
> be acccepted)

Yeah but that's only if we have the limits.iops-total=... options in the
throttle driver. If we "remove limits from the throttle driver options
and only create/config throttle groups via -object/object-add" we cannot
do that.

> Not creating eponymous throttle groups via the throttle driver means
> we don't need throttle_groups anymore, since even anonymous ones don't
> need to be accounted for in a list.

I don't follow you here, how else do you get a group by its name?

Berto