Re: [Qemu-devel] [PATCH 00/12] block: Move I/O throttling to BlockBackend

[Kevin Wolf <kwolf@redhat.com>]

Am 22.03.2016 um 22:33 hat Paolo Bonzini geschrieben:
> On 22/03/2016 16:33, Kevin Wolf wrote:
> > This is another feature that was "logically" part of the BlockBackend, but
> > implemented as a BlockDriverState feature. It was always kept on top using
> > swap_feature_fields().
> > 
> > This series moves it to be actually implemented in the BlockBackend, removing
> > another obstacle for removing bs->blk and allowing multiple BBs per BDS.
> > 
> > Depends on 'block: Implement writethrough in BlockBackend'.
> 
> This series would mess up my own I/O throttling cleanups that have been
> posted in February and have hardly seen a review for one month.

Which cleanups? The ones that you hid in an I/O path locking series?
Whose v2 didn't even include qemu-block? I noticed only now that they
exist.

I can take a look, but nobody told me (or Berto, for that matter) that
this is a series we should have a look at. block/io.c is maintained by
Stefan, throttling isn't.

> I expect the rules for soft freeze to apply to maintainers as well.
> These patches and the removal of bs->blk are about one month late and
> shouldn't be included in 2.6.

This is not a feature. It's a series that brings actual behaviour in
line with the promised API, in other words a bug fix.

Admittedly, it's a very heavy fix, but if we decide that we can't do a
massive bug fix that late in the cycle (I admit that it got a bit late,
even though the initial patches were on time before the soft freeze), we
need to carefully check which other features we must revert in order to
keep the API changes in 2.7 minimal. At least, I think, we'd have to
disallow referencing backing files by node-name in 2.6.

Kevin