[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v2 4/6] Migration: Emit event at start of pass
From: |
Eric Blake |
Subject: |
Re: [Qemu-devel] [PATCH v2 4/6] Migration: Emit event at start of pass |
Date: |
Wed, 16 Dec 2015 09:47:23 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 |
On 12/16/2015 04:47 AM, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
>
> Emit an event each time we sync the dirty bitmap on the source;
> this helps libvirt use postcopy by giving it a kick when it
> might be a good idea to start the postcopy.
>
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> ---
> docs/qmp-events.txt | 14 ++++++++++++++
> migration/ram.c | 4 ++++
> qapi/event.json | 13 +++++++++++++
> 3 files changed, 31 insertions(+)
>
>
> +MIGRATION_PASS
> +--------------
> +
> +Emitted from the source side of a migration at the start of each pass
> +(when it syncs the dirty bitmap)
> +
> +Data: None.
> +
> + - "pass": An incrementing count (starting at 1 on the first pass)
> +
> +Example:
> +{"timestamp": {"seconds": 1449669631, "microseconds": 239225},
> + "event": "MIGRATION_PASS", "data": {"pass": 2}}
How frequently can this event be emitted? It is not under guest
control, so it's harder to argue that it could be abused as a way for
the guest to DoS the host. And hopefully it is slow enough (considering
that each pass also requires lots more effort for actually transmitting
state from source to dest), so I don't think we have to worry about
adding rate-limiting to avoid overwhelming the monitor client.
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake eblake redhat com +1-919-301-3266
Libvirt virtualization library http://libvirt.org
signature.asc
Description: OpenPGP digital signature
- [Qemu-devel] [PATCH v2 0/6] Migration: Small fixes and improvements, Dr. David Alan Gilbert (git), 2015/12/16
- [Qemu-devel] [PATCH v2 3/6] Postcopy: Send events/change state on incoming side, Dr. David Alan Gilbert (git), 2015/12/16
- [Qemu-devel] [PATCH v2 1/6] migration: Export migrate_set_state(), Dr. David Alan Gilbert (git), 2015/12/16
- [Qemu-devel] [PATCH v2 2/6] migration: Add state records for migration incoming, Dr. David Alan Gilbert (git), 2015/12/16
- [Qemu-devel] [PATCH v2 4/6] Migration: Emit event at start of pass, Dr. David Alan Gilbert (git), 2015/12/16
- [Qemu-devel] [PATCH v2 6/6] multithread decompression: Avoid one copy, Dr. David Alan Gilbert (git), 2015/12/16
- [Qemu-devel] [PATCH v2 5/6] Use qemu_get_buffer_in_place for xbzrle data, Dr. David Alan Gilbert (git), 2015/12/16