Re: [PATCH v2 00/22] Fix error handling during bitmap postcopy

[Eric Blake]

On 4/2/20 2:42 AM, Vladimir Sementsov-Ogievskiy wrote:
> Ping!
>
> It's a fix, but not a degradation and I'm afraid too big for 5.0.
>
> Still, I think I should ping it anyway. John, I'm afraid, that this all 
> is for your branch :)

Just noticing this thread, now that we've shuffled bitmaps maintainers. 
Is there anything here that we still need to include in 5.1?

> 17.02.2020 18:02, Vladimir Sementsov-Ogievskiy wrote:
> > Original idea of bitmaps postcopy migration is that bitmaps are non
> > critical data, and their loss is not serious problem. So, using postcopy
> > method on any failure we should just drop unfinished bitmaps and
> > continue guest execution.
> >
> > However, it doesn't work so. It crashes, fails, it goes to
> > postcopy-recovery feature. It does anything except for behavior we want.
> > These series fixes at least some problems with error handling during
> > bitmaps migration postcopy.
> >
> > v1 was "[PATCH 0/7] Fix crashes on early shutdown during bitmaps 
> > postcopy"
> >
> > v2:
> >
> > Most of patches are new or changed a lot.
> > Only patches 06,07 mostly unchanged, just rebased on refactorings.
> >
> > Vladimir Sementsov-Ogievskiy (22):
> >    migration/block-dirty-bitmap: fix dirty_bitmap_mig_before_vm_start
> >    migration/block-dirty-bitmap: rename state structure types
> >    migration/block-dirty-bitmap: rename dirty_bitmap_mig_cleanup
> >    migration/block-dirty-bitmap: move mutex init to dirty_bitmap_mig_init
> >    migration/block-dirty-bitmap: refactor state global variables
> >    migration/block-dirty-bitmap: rename finish_lock to just lock
> >    migration/block-dirty-bitmap: simplify dirty_bitmap_load_complete
> >    migration/block-dirty-bitmap: keep bitmap state for all bitmaps
> >    migration/block-dirty-bitmap: relax error handling in incoming part
> >    migration/block-dirty-bitmap: cancel migration on shutdown
> >    migration/savevm: don't worry if bitmap migration postcopy failed
> >    qemu-iotests/199: fix style
> >    qemu-iotests/199: drop extra constraints
> >    qemu-iotests/199: better catch postcopy time
> >    qemu-iotests/199: improve performance: set bitmap by discard
> >    qemu-iotests/199: change discard patterns
> >    qemu-iotests/199: increase postcopy period
> >    python/qemu/machine: add kill() method
> >    qemu-iotests/199: prepare for new test-cases addition
> >    qemu-iotests/199: check persistent bitmaps
> >    qemu-iotests/199: add early shutdown case to bitmaps postcopy
> >    qemu-iotests/199: add source-killed case to bitmaps postcopy
> >
> > Cc: John Snow <jsnow@redhat.com>
> > Cc: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> > Cc: Stefan Hajnoczi <stefanha@redhat.com>
> > Cc: Fam Zheng <fam@euphon.net>
> > Cc: Juan Quintela <quintela@redhat.com>
> > Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> > Cc: Eduardo Habkost <ehabkost@redhat.com>
> > Cc: Cleber Rosa <crosa@redhat.com>
> > Cc: Kevin Wolf <kwolf@redhat.com>
> > Cc: Max Reitz <mreitz@redhat.com>
> > Cc: qemu-block@nongnu.org
> > Cc: qemu-devel@nongnu.org
> > Cc: qemu-stable@nongnu.org # for patch 01
> >
> >   migration/migration.h          |   3 +-
> >   migration/block-dirty-bitmap.c | 444 +++++++++++++++++++++------------
> >   migration/migration.c          |  15 +-
> >   migration/savevm.c             |  37 ++-
> >   python/qemu/machine.py         |  12 +-
> >   tests/qemu-iotests/199         | 244 ++++++++++++++----
> >   tests/qemu-iotests/199.out     |   4 +-
> >   7 files changed, 529 insertions(+), 230 deletions(-)

--
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org