From: Peter Krempa <pkrempa@redhat.com>
To: Andrey Gruzdev <andrey.gruzdev@virtuozzo.com>
Cc: Juan Quintela <quintela@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
qemu-devel@nongnu.org, Peter Xu <peterx@redhat.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>, Den Lunev <den@openvz.org>
Subject: Re: [PATCH v4 0/6] UFFD write-tracking migration/snapshots
Date: Tue, 1 Dec 2020 08:08:20 +0100 [thread overview]
Message-ID: <20201201070820.GO105758@angien.pipo.sk> (raw)
In-Reply-To: <20201126151734.743849-1-andrey.gruzdev@virtuozzo.com>
On Thu, Nov 26, 2020 at 18:17:28 +0300, Andrey Gruzdev via wrote:
> This patch series is a kind of 'rethinking' of Denis Plotnikov's ideas he's
> implemented in his series '[PATCH v0 0/4] migration: add background snapshot'.
Hi,
I gave this a try when attempting to implement the libvirt code for this
feature. I've ran into a problem of migration failing right away. The
VM's cpus were running at that point.
QEMU logged the following to stdout/err:
2020-12-01T06:50:42.334062Z qemu-system-x86_64: uffd_register_memory() failed: start=7f2007fff000 len=33554432000 mode=2 errno=22
2020-12-01T06:50:42.334072Z qemu-system-x86_64: ram_write_tracking_start() failed: restoring initial memory state
2020-12-01T06:50:42.334074Z qemu-system-x86_64: uffd_protect_memory() failed: start=7f2007fff000 len=33554432000 mode=0 errno=2
2020-12-01T06:50:42.334076Z qemu-system-x86_64: uffd_unregister_memory() failed: start=7f2007fff000 len=33554432000 errno=22
The migration was started by the following QMP conversation:
QEMU_MONITOR_IO_WRITE: mon=0x7fff9c20c610 buf={"execute":"migrate-set-capabilities","arguments":{"capabilities":[{"capability":"xbzrle","state":false},{"capability":"auto-converge","state":false},{"capability":"rdma-pin-all","state":false},{"capability":"postcopy-ram","state":false},{"capability":"compress","state":false},{"capability":"pause-before-switchover","state":false},{"capability":"late-block-activate","state":false},{"capability":"multifd","state":false},{"capability":"background-snapshot","state":true}]},"id":"libvirt-14"}
QEMU_MONITOR_RECV_REPLY: mon=0x7fff9c20c610 reply={"return": {}, "id": "libvirt-14"}
QEMU_MONITOR_IO_WRITE: mon=0x7fff9c20c610 buf={"execute":"migrate-set-parameters","arguments":{"max-bandwidth":9223372036853727232},"id":"libvirt-15"}
QEMU_MONITOR_RECV_REPLY: mon=0x7fff9c20c610 reply={"return": {}, "id": "libvirt-15"}
QEMU_MONITOR_IO_WRITE: mon=0x7fff9c20c610 buf={"execute":"getfd","arguments":{"fdname":"migrate"},"id":"libvirt-16"}
QEMU_MONITOR_IO_SEND_FD: mon=0x7fff9c20c610 fd=44 ret=72 errno=0
QEMU_MONITOR_RECV_REPLY: mon=0x7fff9c20c610 reply={"return": {}, "id": "libvirt-16"}
QEMU_MONITOR_IO_WRITE: mon=0x7fff9c20c610 buf={"execute":"migrate","arguments":{"detach":true,"blk":false,"inc":false,"uri":"fd:migrate"},"id":"libvirt-17"}
QEMU_MONITOR_RECV_EVENT: mon=0x7fff9c20c610 event={"timestamp": {"seconds": 1606805733, "microseconds": 962424}, "event": "MIGRATION", "data": {"status": "setup"}}
QEMU_MONITOR_RECV_REPLY: mon=0x7fff9c20c610 reply={"return": {}, "id": "libvirt-17"}
QEMU_MONITOR_RECV_EVENT: mon=0x7fff9c20c610 event={"timestamp": {"seconds": 1606805733, "microseconds": 966306}, "event": "MIGRATION_PASS", "data": {"pass": 1}}
QEMU_MONITOR_RECV_EVENT: mon=0x7fff9c20c610 event={"timestamp": {"seconds": 1606805733, "microseconds": 966355}, "event": "MIGRATION", "data": {"status": "active"}}
QEMU_MONITOR_RECV_EVENT: mon=0x7fff9c20c610 event={"timestamp": {"seconds": 1606805733, "microseconds": 966488}, "event": "STOP"}
QEMU_MONITOR_RECV_EVENT: mon=0x7fff9c20c610 event={"timestamp": {"seconds": 1606805733, "microseconds": 970326}, "event": "MIGRATION", "data": {"status": "failed"}}
QEMU_MONITOR_IO_WRITE: mon=0x7fff9c20c610 buf={"execute":"query-migrate","id":"libvirt-18"}
QEMU_MONITOR_RECV_REPLY: mon=0x7fff9c20c610 reply={"return": {"status": "failed"}, "id": "libvirt-18"}
qemuMigrationJobCheckStatus:1685 : operation failed: snapshot job: unexpectedly failed
$ uname -r
5.8.18-300.fc33.x86_64
created by libvirt with the following patchset applied:
https://gitlab.com/pipo.sk/libvirt/-/commits/background-snapshot
git fetch https://gitlab.com/pipo.sk/libvirt.git background-snapshot
Start the snapshot via:
virsh snapshot-create-as --memspec /tmp/snap.mem --diskspec sdb,snapshot=no --diskspec sda,snapshot=no --no-metadata upstream
Note you can omit --diskspec if you have a diskless VM.
The patches are VERY work in progress as I need to figure out the proper
sequencing to ensure a consistent snapshot.
Note that in cases when qemu can't guarantee that the
background_snapshot feature will work it should not advertise it. We
need a way to check whether it's possible to use it, so we can replace
the existing --live flag with it rather than adding a new one and
shifting the problem of checking whether the feature works to the user.
next prev parent reply other threads:[~2020-12-01 7:09 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-26 15:17 [PATCH v4 0/6] UFFD write-tracking migration/snapshots Andrey Gruzdev via
2020-11-26 15:17 ` [PATCH v4 1/6] introduce 'background-snapshot' migration capability Andrey Gruzdev via
2020-11-27 19:55 ` Peter Xu
2020-11-28 16:35 ` Andrey Gruzdev
2020-11-26 15:17 ` [PATCH v4 2/6] introduce UFFD-WP low-level interface helpers Andrey Gruzdev via
2020-11-27 21:04 ` Peter Xu
2020-11-29 20:12 ` Andrey Gruzdev
2020-11-30 15:34 ` Peter Xu
2020-11-30 18:41 ` Andrey Gruzdev
2020-12-01 12:24 ` Dr. David Alan Gilbert
2020-12-01 19:32 ` Andrey Gruzdev
2020-11-26 15:17 ` [PATCH v4 3/6] support UFFD write fault processing in ram_save_iterate() Andrey Gruzdev via
2020-11-27 21:49 ` Peter Xu
2020-11-29 21:14 ` Andrey Gruzdev
2020-11-30 16:32 ` Peter Xu
2020-11-30 19:27 ` Andrey Gruzdev
2020-11-26 15:17 ` [PATCH v4 4/6] implementation of background snapshot thread Andrey Gruzdev via
2020-11-26 15:17 ` [PATCH v4 5/6] the rest of write tracking migration code Andrey Gruzdev via
2020-11-27 22:26 ` Peter Xu
2020-11-30 8:09 ` Andrey Gruzdev
2020-11-26 15:17 ` [PATCH v4 6/6] introduce simple linear scan rate limiting mechanism Andrey Gruzdev via
2020-11-27 22:28 ` Peter Xu
2020-11-30 8:11 ` Andrey Gruzdev
2020-11-30 16:40 ` Peter Xu
2020-11-30 19:30 ` Andrey Gruzdev
2020-11-26 15:47 ` [PATCH v4 0/6] UFFD write-tracking migration/snapshots Peter Krempa
2020-11-27 8:21 ` Andrey Gruzdev
2020-11-27 9:49 ` Peter Krempa
2020-11-27 10:00 ` Andrey Gruzdev
2020-11-27 15:45 ` Peter Xu
2020-11-27 17:19 ` Andrey Gruzdev
2020-11-27 22:04 ` Peter Xu
2020-11-30 8:07 ` Andrey Gruzdev
2020-12-01 7:08 ` Peter Krempa [this message]
2020-12-01 8:42 ` Andrey Gruzdev
2020-12-01 10:53 ` Peter Krempa
2020-12-01 11:24 ` Andrey Gruzdev
2020-12-01 18:40 ` Dr. David Alan Gilbert
2020-12-01 19:22 ` Peter Xu
2020-12-01 20:01 ` Dr. David Alan Gilbert
2020-12-01 20:29 ` Andrey Gruzdev
2020-12-01 20:11 ` Andrey Gruzdev
2020-12-01 18:54 ` Peter Xu
2020-12-01 20:00 ` Dr. David Alan Gilbert
2020-12-01 20:26 ` Andrey Gruzdev
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