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Wed, 18 Oct 2023 09:41:51 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.193.56]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 82DF7492BFA; Wed, 18 Oct 2023 09:41:51 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 7C24621E6A1F; Wed, 18 Oct 2023 11:41:50 +0200 (CEST) From: Markus Armbruster To: Fiona Ebner Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, armbru@redhat.com, eblake@redhat.com, hreitz@redhat.com, kwolf@redhat.com, vsementsov@yandex-team.ru, jsnow@redhat.com, den@virtuozzo.com, t.lamprecht@proxmox.com, alexander.ivanov@virtuozzo.com Subject: Re: [PATCH v3 0/9] mirror: allow switching from background to active mode References: <20231013092143.365296-1-f.ebner@proxmox.com> Date: Wed, 18 Oct 2023 11:41:50 +0200 In-Reply-To: <20231013092143.365296-1-f.ebner@proxmox.com> (Fiona Ebner's message of "Fri, 13 Oct 2023 11:21:34 +0200") Message-ID: <87lec0uv1d.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.10 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Fiona Ebner writes: > Changes in v3: > * unlock the job mutex when calling the new block job driver > 'query' handler > * squash patch adapting iotest output into patch that changes the > output > * turn accesses to copy_mode and actively_synced atomic > * slightly rework error handling in mirror_change > > Changes in v2: > * move bitmap to filter which allows to avoid draining when > changing the copy mode > * add patch to determine copy_to_target only once > * drop patches returning redundant information upon query > * update QEMU version in QAPI > * update indentation in QAPI > * update indentation in QAPI (like in a937b6aa73 ("qapi: Reformat > doc comments to conform to current conventions")) > * add patch to adapt iotest output > > Discussion of v2: > https://lists.nongnu.org/archive/html/qemu-devel/2023-10/msg02290.html > > Discussion of v1: > https://lists.nongnu.org/archive/html/qemu-devel/2023-02/msg07216.html > > With active mode, the guest write speed is limited by the synchronous > writes to the mirror target. For this reason, management applications > might want to start out in background mode and only switch to active > mode later, when certain conditions are met. This series adds a > block-job-change QMP command to achieve that, as well as > job-type-specific information when querying block jobs, which > can be used to decide when the switch should happen. > > For now, only the direction background -> active is supported. > > The information added upon querying is whether the target is actively > synced, the total data sent, and the remaining dirty bytes. > > Initially, I tried to go for a more general 'job-change' command, but > to avoid mutual inclusion of block-core.json and job.json, more > preparation would be required. Can you elaborate a bit? A more generic command is preferable, and we need to understand what it would take.