From: John Snow <jsnow@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>,
Eduardo Habkost <ehabkost@redhat.com>,
qemu-block@nongnu.org, qemu-devel <qemu-devel@nongnu.org>,
Hanna Reitz <hreitz@redhat.com>, Cleber Rosa <crosa@redhat.com>
Subject: Re: [PATCH v5 2/8] python/machine: Handle QMP errors on close more meticulously
Date: Thu, 28 Oct 2021 11:35:43 -0400 [thread overview]
Message-ID: <CAFn=p-bdJ05=z6KBiHKsMSPjDAZoJ59iJjKGnRhZ97vasyz38g@mail.gmail.com> (raw)
In-Reply-To: <YXp05svPZwSXOA/d@redhat.com>
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On Thu, Oct 28, 2021, 6:01 AM Kevin Wolf <kwolf@redhat.com> wrote:
> Am 27.10.2021 um 19:49 hat John Snow geschrieben:
> > This reply is long, sorry.
>
> And after writing half of a very long reply myself, I noticed that I was
> just very confused, so sorry for making you write a long text for no
> real reason (well, at least for my first point - for the second one,
> your explanation was very helpful, so thanks for that).
>
> Somehow I ended up completely ignoring the context of the code (it's run
> as part of shutdown functions) and instead thought of the general
> condition of QMP connections going away anywhere in the code.
>
> I suppose this could be a relevant concern in an actually asynchronous
> client that may read from the socket (and encounter an error if the QEMU
> process has already gone away and closed the connection) at any time,
> but that's not what machine.py is meant for, at least not for now.
>
> So I'll just delete what I already wrote. This patch should be fine.
>
> Kevin
>
No problem. The cleanup path here is quite complex, so it wasn't clear that
there *wasn't* a problem.
I'd like to upgrade machine.py to use asyncio more natively for the console
socket and qmp layers in the future and help break it apart into smaller
pieces that are easier to reason about.
You're right, though, if/when this part becomes async then needing more
precision on when we mark a vm as defunct will become important.
Thanks for looking at it!
--js
>
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next prev parent reply other threads:[~2021-10-28 15:37 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-26 17:56 [PATCH v5 0/8] Switch iotests to using Async QMP John Snow
2021-10-26 17:56 ` [PATCH v5 1/8] python/machine: remove has_quit argument John Snow
2021-10-26 17:56 ` [PATCH v5 2/8] python/machine: Handle QMP errors on close more meticulously John Snow
2021-10-27 11:19 ` Kevin Wolf
2021-10-27 17:49 ` John Snow
2021-10-28 10:01 ` Kevin Wolf
2021-10-28 15:35 ` John Snow [this message]
2021-10-26 17:56 ` [PATCH v5 3/8] python/aqmp: Remove scary message John Snow
2021-10-26 17:56 ` [PATCH v5 4/8] iotests: Accommodate async QMP Exception classes John Snow
2021-10-26 17:56 ` [PATCH v5 5/8] iotests: Conditionally silence certain AQMP errors John Snow
2021-10-26 17:56 ` [PATCH v5 6/8] iotests/300: avoid abnormal shutdown race condition John Snow
2021-10-27 12:56 ` Kevin Wolf
2021-10-27 17:55 ` John Snow
2021-10-26 17:56 ` [PATCH v5 7/8] python/aqmp: Create sync QMP wrapper for iotests John Snow
2021-10-26 17:56 ` [PATCH v5 8/8] python, iotests: replace qmp with aqmp John Snow
2021-10-28 10:37 ` [PATCH v5 0/8] Switch iotests to using Async QMP Kevin Wolf
2021-10-28 14:48 ` John Snow
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