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Tue, 1 Sep 2020 14:38:47 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 157F0113C418; Tue, 1 Sep 2020 16:38:46 +0200 (CEST) From: Markus Armbruster To: Lukas Straub Subject: Re: [PATCH v8 1/8] Introduce yank feature References: Date: Tue, 01 Sep 2020 16:38:46 +0200 In-Reply-To: (Lukas Straub's message of "Tue, 1 Sep 2020 11:15:07 +0200") Message-ID: <874kohsgsp.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0.001 X-Mimecast-Originator: redhat.com Content-Type: text/plain Received-SPF: pass client-ip=207.211.31.81; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/01 02:08:15 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , =?utf-8?Q?Daniel_P=2E_Berrang=C3=A9?= , qemu-block , Juan Quintela , Markus Armbruster , qemu-devel , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Paolo Bonzini , Max Reitz , "Dr. David Alan Gilbert" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" One more question... Lukas Straub writes: > The yank feature allows to recover from hanging qemu by "yanking" > at various parts. Other qemu systems can register themselves and > multiple yank functions. Then all yank functions for selected > instances can be called by the 'yank' out-of-band qmp command. > Available instances can be queried by a 'query-yank' oob command. > > Signed-off-by: Lukas Straub > Acked-by: Stefan Hajnoczi [...] > diff --git a/qapi/misc.json b/qapi/misc.json > index 9d32820dc1..7de330416a 100644 > --- a/qapi/misc.json > +++ b/qapi/misc.json > @@ -1615,3 +1615,65 @@ > ## > { 'command': 'query-vm-generation-id', 'returns': 'GuidInfo' } > > +## > +# @YankInstances: > +# > +# @instances: List of yank instances. > +# > +# A yank instance can be yanked with the "yank" qmp command to recover from a > +# hanging qemu. > +# > +# Yank instances are named after the following schema: > +# "blockdev:" refers to a block device. Currently only nbd block > +# devices are implemented. > +# "chardev:" refers to a chardev. Currently only socket chardevs > +# are implemented. > +# "migration" refers to the migration currently in progress. > +# > +# Currently implemented yank instances: > +# -nbd block device: > +# Yanking it will shutdown the connection to the nbd server without > +# attempting to reconnect. > +# -socket chardev: > +# Yanking it will shutdown the connected socket. > +# -migration: > +# Yanking it will shutdown all migration connections. How is yanking migration related to command migrate_cancel? > +# > +# Since: 5.2 > +## > +{ 'struct': 'YankInstances', 'data': {'instances': ['str'] } } > + > +## > +# @yank: > +# > +# Recover from hanging qemu by yanking the specified instances. See > +# "YankInstances" for more information. > +# > +# Takes @YankInstances as argument. > +# > +# Returns: nothing. > +# > +# Example: > +# > +# -> { "execute": "yank", "arguments": { "instances": ["blockdev:nbd0"] } } > +# <- { "return": {} } > +# > +# Since: 5.2 > +## > +{ 'command': 'yank', 'data': 'YankInstances', 'allow-oob': true } > + > +## > +# @query-yank: > +# > +# Query yank instances. See "YankInstances" for more information. > +# > +# Returns: @YankInstances > +# > +# Example: > +# > +# -> { "execute": "query-yank" } > +# <- { "return": { "instances": ["blockdev:nbd0"] } } > +# > +# Since: 5.2 > +## > +{ 'command': 'query-yank', 'returns': 'YankInstances', 'allow-oob': true } [...]