From: Peter Xu <peterx@redhat.com>
To: "Daniel P. Berrangé" <berrange@redhat.com>
Cc: Fabiano Rosas <farosas@suse.de>,
qemu-devel@nongnu.org, armbru@redhat.com,
Juan Quintela <quintela@redhat.com>,
Leonardo Bras <leobras@redhat.com>,
Claudio Fontana <cfontana@suse.de>,
Eric Blake <eblake@redhat.com>
Subject: Re: [PATCH v2 06/29] migration: Add auto-pause capability
Date: Wed, 25 Oct 2023 11:36:27 -0400 [thread overview]
Message-ID: <ZTk1++TzE+SiT3UH@x1n> (raw)
In-Reply-To: <ZTkzY0nKtdeZJojP@redhat.com>
On Wed, Oct 25, 2023 at 04:25:23PM +0100, Daniel P. Berrangé wrote:
> > Libvirt will still use fixed-ram for live snapshot purpose, especially for
> > Windows? Then auto-pause may still be useful to identify that from what
> > Fabiano wants to achieve here (which is in reality, non-live)?
> >
> > IIRC of previous discussion that was the major point that libvirt can still
> > leverage fixed-ram for a live case - since Windows lacks efficient live
> > snapshot (background-snapshot feature).
>
> Libvirt will use fixed-ram for all APIs it has that involve saving to
> disk, with CPUs both running and paused.
There are still two scenarios. How should we identify them, then? For
sure we can always make it live, but QEMU needs that information to make it
efficient for non-live.
Considering when there's no auto-pause, then Libvirt will still need to
know the scenario first then to decide whether pausing VM before migration
or do nothing, am I right?
If so, can Libvirt replace that "pause VM" operation with setting
auto-pause=on here? Again, the benefit is QEMU can benefit from it.
I think when pausing Libvirt can still receive an event, then it can
cooperate with state changes? Meanwhile auto-pause=on will be set by
Libvirt too, so Libvirt will even have that expectation that QMP migrate
later on will pause the VM.
>
> > From that POV it sounds like auto-pause is a good knob for that.
>
> From libvirt's POV auto-pause will create extra work for integration
> for no gain.
Yes, I agree for Libvirt there's no gain, as the gain is on QEMU's side.
Could you elaborate what is the complexity for Libvirt to support it?
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2023-10-25 15:37 UTC|newest]
Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-23 20:35 [PATCH v2 00/29] migration: File based migration with multifd and fixed-ram Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 01/29] tests/qtest: migration events Fabiano Rosas
2023-10-25 9:44 ` Thomas Huth
2023-10-25 10:14 ` Daniel P. Berrangé
2023-10-25 13:21 ` Fabiano Rosas
2023-10-25 13:33 ` Steven Sistare
2023-10-23 20:35 ` [PATCH v2 02/29] tests/qtest: Move QTestMigrationState to libqtest Fabiano Rosas
2023-10-25 10:17 ` Daniel P. Berrangé
2023-10-25 13:19 ` Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 03/29] tests/qtest: Allow waiting for migration events Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 04/29] migration: Return the saved state from global_state_store Fabiano Rosas
2023-10-25 10:19 ` Daniel P. Berrangé
2023-10-23 20:35 ` [PATCH v2 05/29] migration: Introduce global_state_store_once Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 06/29] migration: Add auto-pause capability Fabiano Rosas
2023-10-24 5:25 ` Markus Armbruster
2023-10-24 18:12 ` Fabiano Rosas
2023-10-25 5:33 ` Markus Armbruster
2023-10-25 8:48 ` Daniel P. Berrangé
2023-10-25 13:57 ` Fabiano Rosas
2023-10-25 14:20 ` Daniel P. Berrangé
2023-10-25 14:58 ` Peter Xu
2023-10-25 15:25 ` Daniel P. Berrangé
2023-10-25 15:36 ` Peter Xu [this message]
2023-10-25 15:40 ` Daniel P. Berrangé
2023-10-25 17:20 ` Peter Xu
2023-10-25 17:31 ` Daniel P. Berrangé
2023-10-25 19:28 ` Peter Xu
2023-10-23 20:35 ` [PATCH v2 07/29] migration: Run "file:" migration with a stopped VM Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 08/29] tests/qtest: File migration auto-pause tests Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 09/29] io: add and implement QIO_CHANNEL_FEATURE_SEEKABLE for channel file Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 10/29] io: Add generic pwritev/preadv interface Fabiano Rosas
2023-10-24 8:18 ` Daniel P. Berrangé
2023-10-24 19:06 ` Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 11/29] io: implement io_pwritev/preadv for QIOChannelFile Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 12/29] migration/qemu-file: add utility methods for working with seekable channels Fabiano Rosas
2023-10-25 10:22 ` Daniel P. Berrangé
2023-10-23 20:35 ` [PATCH v2 13/29] migration: fixed-ram: Add URI compatibility check Fabiano Rosas
2023-10-25 10:27 ` Daniel P. Berrangé
2023-10-31 16:06 ` Peter Xu
2023-10-23 20:35 ` [PATCH v2 14/29] migration/ram: Introduce 'fixed-ram' migration capability Fabiano Rosas
2023-10-24 5:33 ` Markus Armbruster
2023-10-24 18:35 ` Fabiano Rosas
2023-10-25 6:18 ` Markus Armbruster
2023-10-23 20:35 ` [PATCH v2 15/29] migration/ram: Add support for 'fixed-ram' outgoing migration Fabiano Rosas
2023-10-25 9:39 ` Daniel P. Berrangé
2023-10-25 14:03 ` Fabiano Rosas
2023-11-01 15:23 ` Peter Xu
2023-11-01 15:52 ` Daniel P. Berrangé
2023-11-01 16:24 ` Peter Xu
2023-11-01 16:37 ` Daniel P. Berrangé
2023-11-01 17:30 ` Peter Xu
2023-10-31 16:52 ` Peter Xu
2023-10-31 17:33 ` Fabiano Rosas
2023-10-31 17:59 ` Peter Xu
2023-10-23 20:35 ` [PATCH v2 16/29] migration/ram: Add support for 'fixed-ram' migration restore Fabiano Rosas
2023-10-25 9:43 ` Daniel P. Berrangé
2023-10-25 14:07 ` Fabiano Rosas
2023-10-31 19:03 ` Peter Xu
2023-11-01 9:26 ` Daniel P. Berrangé
2023-11-01 14:21 ` Peter Xu
2023-11-01 14:28 ` Daniel P. Berrangé
2023-11-01 15:00 ` Peter Xu
2023-11-06 13:18 ` Fabiano Rosas
2023-11-06 21:00 ` Peter Xu
2023-11-07 9:02 ` Daniel P. Berrangé
2023-10-31 19:09 ` Peter Xu
2023-10-31 20:00 ` Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 17/29] tests/qtest: migration-test: Add tests for fixed-ram file-based migration Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 18/29] migration/multifd: Allow multifd without packets Fabiano Rosas
2023-10-23 20:35 ` [PATCH v2 19/29] migration/multifd: Add outgoing QIOChannelFile support Fabiano Rosas
2023-10-25 9:52 ` Daniel P. Berrangé
2023-10-25 14:12 ` Fabiano Rosas
2023-10-25 14:23 ` Daniel P. Berrangé
2023-10-25 15:00 ` Fabiano Rosas
2023-10-25 15:26 ` Daniel P. Berrangé
2023-10-31 20:11 ` Peter Xu
2023-10-23 20:35 ` [PATCH v2 20/29] migration/multifd: Add incoming " Fabiano Rosas
2023-10-25 10:29 ` Daniel P. Berrangé
2023-10-25 14:18 ` Fabiano Rosas
2023-10-31 21:28 ` Peter Xu
2023-10-23 20:36 ` [PATCH v2 21/29] migration/multifd: Add pages to the receiving side Fabiano Rosas
2023-10-31 22:10 ` Peter Xu
2023-10-31 23:18 ` Fabiano Rosas
2023-11-01 15:55 ` Peter Xu
2023-11-01 17:20 ` Fabiano Rosas
2023-11-01 17:35 ` Peter Xu
2023-11-01 18:14 ` Fabiano Rosas
2023-10-23 20:36 ` [PATCH v2 22/29] io: Add a pwritev/preadv version that takes a discontiguous iovec Fabiano Rosas
2023-10-24 8:50 ` Daniel P. Berrangé
2023-10-23 20:36 ` [PATCH v2 23/29] migration/ram: Add a wrapper for fixed-ram shadow bitmap Fabiano Rosas
2023-11-01 14:29 ` Peter Xu
2023-10-23 20:36 ` [PATCH v2 24/29] migration/ram: Ignore multifd flush when doing fixed-ram migration Fabiano Rosas
2023-10-25 9:09 ` Daniel P. Berrangé
2023-10-23 20:36 ` [PATCH v2 25/29] migration/multifd: Support outgoing fixed-ram stream format Fabiano Rosas
2023-10-25 9:23 ` Daniel P. Berrangé
2023-10-25 14:21 ` Fabiano Rosas
2023-10-23 20:36 ` [PATCH v2 26/29] migration/multifd: Support incoming " Fabiano Rosas
2023-10-23 20:36 ` [PATCH v2 27/29] tests/qtest: Add a multifd + fixed-ram migration test Fabiano Rosas
2023-10-23 20:36 ` [PATCH v2 28/29] migration: Add direct-io parameter Fabiano Rosas
2023-10-24 5:41 ` Markus Armbruster
2023-10-24 19:32 ` Fabiano Rosas
2023-10-25 6:23 ` Markus Armbruster
2023-10-25 8:44 ` Daniel P. Berrangé
2023-10-25 14:32 ` Fabiano Rosas
2023-10-25 14:43 ` Daniel P. Berrangé
2023-10-25 17:30 ` Fabiano Rosas
2023-10-25 17:45 ` Daniel P. Berrangé
2023-10-25 18:10 ` Fabiano Rosas
2023-10-30 22:51 ` Fabiano Rosas
2023-10-31 9:03 ` Daniel P. Berrangé
2023-10-31 13:05 ` Fabiano Rosas
2023-10-31 13:45 ` Daniel P. Berrangé
2023-10-31 14:33 ` Fabiano Rosas
2023-10-31 15:22 ` Daniel P. Berrangé
2023-10-31 15:52 ` Fabiano Rosas
2023-10-31 15:58 ` Daniel P. Berrangé
2023-10-31 19:05 ` Fabiano Rosas
2023-11-01 9:30 ` Daniel P. Berrangé
2023-11-01 12:16 ` Fabiano Rosas
2023-11-01 12:23 ` Daniel P. Berrangé
2023-11-01 12:30 ` Fabiano Rosas
2023-10-24 8:33 ` Daniel P. Berrangé
2023-10-24 19:06 ` Fabiano Rosas
2023-10-25 9:07 ` Daniel P. Berrangé
2023-10-25 14:48 ` Fabiano Rosas
2023-10-25 15:22 ` Daniel P. Berrangé
2023-10-23 20:36 ` [PATCH v2 29/29] tests/qtest: Add a test for migration with direct-io and multifd Fabiano Rosas
2023-10-25 9:25 ` Daniel P. Berrangé
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