Re: [Qemu-devel] [PATCH COLO-Frame v8 00/34] COarse-grain LOck-stepping(COLO) Virtual Machines for Non-stop Service (FT)

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* zhanghailiang (zhang.zhanghailiang@huawei.com) wrote:
> This is the 8th version of COLO.

I'm seeing an occasional error:

  pcibus_reset: Assertion `bus->irq_count[i] == 0' failed.

on the secondary; have you seen that?

bus->irq_count[4] is -1 in my backtrace; it's
colo_process_incoming_checkpoints->qemu_devices_reset->qbus_walk_children->qbus_reset_one->pcibus_reset

Dave

> Here is only COLO frame part, include: VM checkpoint,
> failover, proxy API, block replication API, not include block replication.
> The block part is treated as a separate series.
> 
> As usual, we provide 'basic' and 'developing' branches in github:
> https://github.com/coloft/qemu/commits/colo-v1.5-basic
> https://github.com/coloft/qemu/commits/colo-v1.5-developing (more features)
> 
> The 'basic' branch is exactly the same with this patch series,
> We will keep this series simple as possible, just for easy review.
> 
> The extra features in colo-v1.5-developing branch:
> 1) Separate ram and device save/load process to reduce size of extra memory
> used during checkpoint
> 2) Live migrate part of dirty pages to slave during sleep time.
> 3) You get the statistic info about checkpoint by command 'info migrate'
> 
> Please reference to the follow link to test COLO.
> http://wiki.qemu.org/Features/COLO.
> 
> COLO is a totally new feature which is still in early stage,
> your comments and feedback are warmly welcomed.
> 
> NOTE:
> We have decided to re-implement the colo proxy in userspace (In qemu exactly).
> you can find the discussion about why & how to realize the colo proxy in qemu from the follow link:
> http://lists.nongnu.org/archive/html/qemu-devel/2015-07/msg04069.html
> 
> TODO:
> 1. COLO function switch on/off
> 2. The capability of continuous FT
> 3. Optimize the performance.
> 
> v8:
> - Move some global variables into MigrationIncomingState and MigrationState
> - Move some cleanup work form colo thread and colo incoming thread into failover
>   BH function and also fix the code logic for the cleanup work.
> - fix the bug that colo thread and colo incoming thread possibly block in the
>   socket 'recv' call when do failover work.
> - Optimize colo_flush_ram_cache()
> - Add migration state for incoming side, we use the state to verify if migration
>   incoming side is in COLO state or not (Patch 5).
> - Drop the patch 'COLO: Disable qdev hotplug when VM is in COLO mode', since it is not correct. 
> 
> zhanghailiang (34):
>   configure: Add parameter for configure to enable/disable COLO support
>   migration: Introduce capability 'colo' to migration
>   COLO: migrate colo related info to slave
>   colo-comm/migration: skip colo info section for special cases
>   migration: Add state records for migration incoming
>   migration: Integrate COLO checkpoint process into migration
>   migration: Integrate COLO checkpoint process into loadvm
>   COLO: Implement colo checkpoint protocol
>   COLO: Add a new RunState RUN_STATE_COLO
>   QEMUSizedBuffer: Introduce two help functions for qsb
>   COLO: Save VM state to slave when do checkpoint
>   COLO RAM: Load PVM's dirty page into SVM's RAM cache temporarily
>   COLO VMstate: Load VM state into qsb before restore it
>   arch_init: Start to trace dirty pages of SVM
>   COLO RAM: Flush cached RAM into SVM's memory
>   COLO failover: Introduce a new command to trigger a failover
>   COLO failover: Introduce state to record failover process
>   COLO failover: Implement COLO primary/secondary vm failover work
>   qmp event: Add event notification for COLO error
>   COLO failover: Don't do failover during loading VM's state
>   COLO: Add new command parameter 'forward_nic' 'colo_script' for net
>   COLO NIC: Init/remove colo nic devices when add/cleanup tap devices
>   tap: Make launch_script() public
>   COLO NIC: Implement colo nic device interface configure()
>   colo-nic: Handle secondary VM's original net device configure
>   COLO NIC: Implement colo nic init/destroy function
>   COLO NIC: Some init work related with proxy module
>   COLO: Handle nfnetlink message from proxy module
>   COLO: Do checkpoint according to the result of packets comparation
>   COLO: Improve checkpoint efficiency by do additional periodic
>     checkpoint
>   COLO: Add colo-set-checkpoint-period command
>   COLO NIC: Implement NIC checkpoint and failover
>   COLO: Implement shutdown checkpoint
>   COLO: Add block replication into colo process
> 
>  configure                     |  33 +-
>  docs/qmp/qmp-events.txt       |  16 +
>  hmp-commands.hx               |  30 ++
>  hmp.c                         |  15 +
>  hmp.h                         |   2 +
>  include/exec/cpu-all.h        |   1 +
>  include/migration/colo.h      |  45 +++
>  include/migration/failover.h  |  33 ++
>  include/migration/migration.h |  19 +
>  include/migration/qemu-file.h |   3 +-
>  include/net/colo-nic.h        |  37 ++
>  include/net/net.h             |   2 +
>  include/net/tap.h             |  19 +
>  include/sysemu/sysemu.h       |   3 +
>  migration/Makefile.objs       |   2 +
>  migration/colo-comm.c         |  75 ++++
>  migration/colo-failover.c     |  83 +++++
>  migration/colo.c              | 805 ++++++++++++++++++++++++++++++++++++++++++
>  migration/migration.c         | 116 ++++--
>  migration/qemu-file-buf.c     |  58 +++
>  migration/ram.c               | 242 ++++++++++++-
>  migration/savevm.c            |   2 +-
>  net/Makefile.objs             |   1 +
>  net/colo-nic.c                | 457 ++++++++++++++++++++++++
>  net/net.c                     |   2 +
>  net/tap.c                     |  90 +++--
>  qapi-schema.json              |  58 ++-
>  qapi/event.json               |  15 +
>  qemu-options.hx               |   7 +
>  qmp-commands.hx               |  42 +++
>  scripts/colo-proxy-script.sh  | 145 ++++++++
>  stubs/Makefile.objs           |   1 +
>  stubs/migration-colo.c        |  58 +++
>  trace-events                  |  10 +
>  vl.c                          |  37 +-
>  35 files changed, 2474 insertions(+), 90 deletions(-)
>  create mode 100644 include/migration/colo.h
>  create mode 100644 include/migration/failover.h
>  create mode 100644 include/net/colo-nic.h
>  create mode 100644 migration/colo-comm.c
>  create mode 100644 migration/colo-failover.c
>  create mode 100644 migration/colo.c
>  create mode 100644 net/colo-nic.c
>  create mode 100755 scripts/colo-proxy-script.sh
>  create mode 100644 stubs/migration-colo.c
> 
> -- 
> 1.8.3.1
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK