[dm-devel] [PATCH V3] blk-mq: introduce BLK_STS_DEV_RESOURCE

[Bart Van Assche]

On Sat, 2018-01-27 at 23:58 -0500, Mike Snitzer wrote:
> On Sat, Jan 27 2018 at 10:00pm -0500,
> Bart Van Assche <Bart.VanAssche at wdc.com> wrote:
> 
> > On Sat, 2018-01-27 at 21:03 -0500, Mike Snitzer wrote:
> > > You cannot even be forthcoming about the technical merit of a change you
> > > authored (commit 6077c2d70) that I'm left to clean up in the face of
> > > performance bottlenecks it unwittingly introduced?  If you were being
> > > honest: you'd grant that the random delay of 100ms is utterly baseless
> > > (not to mention that kicking the queue like you did is a complete
> > > hack).  So that 100ms delay is what my dm-4.16 commit is talking about.
> > 
> > There are multiple errors in the above:
> > 1. I have already explained in detail why commit 6077c2d70 is (a) correct
> >    and (b) essential. See e.g. https://www.redhat.com/archives/dm-devel/2018-January/msg00168.html.
> 
> And you'd be wrong.  Again.  We've already established that commit
> 6077c2d70 is _not_ essential.  Ming's V3, in conjunction with all the
> changes that already went into block and DM for 4.16, prove that.

What I wrote was right when commit 6077c2d70 got introduced. My explanation
shows that at that time  was both correct and essential. Ming's v3 is in my
opinion not relevant yet to this discussion because it introduces new bugs
and so far no attempt has been made to address these bugs.

> > 2. With patch "blk-mq: Avoid that blk_mq_delay_run_hw_queue() introduces
> >    unintended delays" applied, there is nothing to clean up anymore since
> >    that patch eliminates the queue delays that were triggered by
> >    blk_mq_delay_run_hw_queue().
> 
> The issue Ming fixed is that your random queue kicks break RESTART on
> dm-mq mpath.

That comment is too short to be comprehensible for anyone. Can you elaborate
this further?

> > 3. You know that I'm honest. Suggesting that I'm not is wrong.
> 
> No, I trully do _not_ know you're always honest.  You've conflated so
> many details on this topic that it makes me have serious doubts.  You're
> lashing out so much, in defense of your dm_mq_queue_rq delayed queue
> kick, that you're missing there is a genuine generic blk-mq problem that
> is getting fixed in Ming's V3.
> 
> [ ... ]
>
> Bart, the number of emails exchanged on this topic has exhausted
> _everyone_.  Emotions get tense when things don't evolve despite every
> oppotunity for progress to be realized.  When people cling to solutions
> that are no longer relevant.  There is a very real need for progress
> here.  So either get out of the way or suggest a specific series of
> change(s) that you feel better than Ming's V3.

If you and Ming really care about the approach in the patch at the start
of this e-mail thread, what are you waiting for to address the technical
shortcomings that I pointed out?

> With that, I'll also stop responding to your baiting now and forevermore
> (e.g. "maintainers should this.. and maintainers should not that" or
> "your employer is not investing adequately".  Next time you find
> yourself typing drivel like that: spare us all and hit delete).

My opinion about what you wrote in this and the other e-mails you sent to
me during the past months is as follows:
1. That I have always done my best to provide all the relevant technical
   information.
2. That my focus was on the technical aspects of the discussion.
3. That you did not try to reach a consensus but rather to dominate the
   discussion.
4. That the tone of your e-mails was very aggressive.
5. That you insulted me several times personally.

I believe that your behavior is a violation of the kernel code of conflict
and sufficient to file a complaint with the TAB. From
Documentation/process/code-of-conflict.rst:

"If however, anyone feels personally abused, threatened, or otherwise
uncomfortable due to this process, that is not acceptable.  If so,
please contact the Linux Foundation's Technical Advisory Board [ ... ]"

Additionally, since you are a U.S. Citizen, you should know that what you
wrote in previous e-mails amounts to libel. A quote from a definition of
libel: "to publish in print (including pictures), writing or broadcast
through radio, television or film, an untruth about another which will do
harm to that person or his/her reputation, by tending to bring the target
into ridicule, hatred, scorn or contempt of others." You should be aware
since I live in the U.S. that this makes it possible for me to sue you for
defamation and to ask for a compensation.

Bart.