Re: [Qemu-devel] [PATCH v2 05/12] mirror: perform COW if the cluster size is bigger than the granularity

[Stefan Hajnoczi]

On Mon, Jan 21, 2013 at 12:15:51PM +0100, Paolo Bonzini wrote:
> Il 21/01/2013 11:17, Kevin Wolf ha scritto:
> > Am 18.01.2013 18:33, schrieb Paolo Bonzini:
> >>
> >>> Am 18.01.2013 17:22, schrieb Paolo Bonzini:
> >>>> I haven't written a testcase for it, it's tricky but should be
> >>>> doable.
> >>>> Do you want me to respin, or can it be done as a followup?
> >>>
> >>> I think I would prefer a respin, but if you think otherwise, I won't
> >>> insist.
> >>
> >> Okay, I'll respin.  I'll just note that this series now is in danger of
> >> missing 1.4 (after 1.2 and 1.3) because only Laszlo and Eric gave it a
> >> decent review in the six months since it was first posted.
> >>
> >> Had I been employed by any other company, I'd probably just have kept
> >> the code in house and forgotten about upstream.
> > 
> > I hope this doesn't imply that you feel I'm happy or even just
> > indifferent about it. This is just what happens when you get a huge
> > numbers of patches and have only very few reviewers. I hope it has got a
> > bit better since Stefan supports me in maintaining the block layer, but
> > I'm afraid we're still not good enough with it. Any helpful suggestions
> > are appreciated.
> 
> No, I don't think you're happy.  And I'm sorry if it felt like a
> complaint, it wasn't meant to be---I had plenty of other patches
> committed by either you or Stefan or Anthony, so I cannot really
> complain about anything. :)
> 
> The problem is that we have lots of patches that are not ready posted
> too early without really following comments.  These patches consume a
> huge amount of review bandwidth.  And more often than not are never
> committed because people disappear when they are almost ready.

This is due to growth.  QEMU is attracting new contributors all the
time.  Their new features need more integration help not just because
the contributors are new the QEMU codebase, but also because the
features stretch the boundaries of what QEMU is designed for.

I'd rather that RFC series are posted and slowly digested by the
community than the alternatives, which are throwing "finished" code over
the wall without prior discussion (and the contributor is faced with big
change requests from the community, gets frustrated because they thought
it was done, and leaves) or simply keeping code out of the QEMU source
tree altogether.

> At the same time, patches that are almost ready from the beginning, tend
> to fall through the cracks.  It is not exclusive to the block layer, see
> for example Alberto Garcia's serial port patches.

We need more reviewers.  I've noticed Eric Blake doing a lot of good
code review over the past months.  When people review code it frees up
maintainers to spend more time applying patches.

Stefan