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Re: [Qemu-devel] [RFC PATCH v4 00/28] COarse-grain LOck-stepping(COLO) V
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [RFC PATCH v4 00/28] COarse-grain LOck-stepping(COLO) Virtual Machines for Non-stop Service |
Date: |
Wed, 22 Apr 2015 12:18:34 +0100 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
* zhanghailiang (address@hidden) wrote:
> Hi,
>
> ping ...
I will get to look at this again; but not until after next week.
> The main blocked bugs for COLO have been solved,
I've got the v3 set running, but the biggest problem I hit are problems
with the packet comparison module; I've seen a panic which I think is
in colo_send_checkpoint_req that I think is due to the use of
GFP_KERNEL to allocate the netlink message and I think it can schedule
there. I tried making that a GFP_ATOMIC but I'm hitting other
problems with :
kcolo_thread, no conn, schedule out
that I've not had time to look into yet.
So I only get about a 50% success rate of starting COLO.
I see there are stuff in the TODO of the colo-proxy that
seem to say the netlink stuff should change, maybe you're already fixing
that?
> we also have finished some new features and optimization on COLO. (If you are
> interested in this,
> we can send them to you in private ;))
> For easy of review, it is better to keep it simple now, so we will not add
> too much new codes into this frame
> patch set before it been totally reviewed.
I'd like to see those; but I don't want to take code privately.
It's OK to post extra stuff as a separate set.
> COLO is a totally new feature which is still in early stage, we hope to speed
> up the development,
> so your comments and feedback are warmly welcomed. :)
Yes, it's getting there though; I don't think anyone else has
got this close to getting a full FT set working with disk and networking.
Dave
>
> Thanks,
> zhanghailiang
>
> On 2015/3/26 13:29, zhanghailiang wrote:
> >This is the 4th version of COLO, here is only COLO frame part, include: VM
> >checkpoint,
> >failover, proxy API, block replication API, not include block replication.
> >The block part has been sent by wencongyang:
> >[RFC PATCH COLO v2 00/13] Block replication for continuous checkpoints
> >
> >Compared with last version, there aren't too much optimize and new functions.
> >The main reason is that there is an known issue that still unsolved, we found
> >some dirty pages which have been missed setting bit in corresponding bitmap.
> >And it will trigger strange problem in VM.
> >We hope to resolve it before add more codes.
> >
> >You can get the newest integrated qemu colo patches from github:
> >https://github.com/coloft/qemu/commits/colo-v1.1
> >
> >About how to test COLO, Please reference to the follow link.
> >http://wiki.qemu.org/Features/COLO.
> >
> >Please review and test.
> >
> >Known issue still unsolved:
> >(1) Some pages dirtied without setting its corresponding dirty-bitmap.
> >
> >Previous posted RFC patch series:
> >http://lists.nongnu.org/archive/html/qemu-devel/2014-06/msg05567.html
> >http://lists.nongnu.org/archive/html/qemu-devel/2014-09/msg04459.html
> >https://lists.gnu.org/archive/html/qemu-devel/2015-02/msg04771.html
> >
> >TODO list:
> >1 Optimize the process of checkpoint, shorten the time-consuming:
> > (Partly done, patch is not include into this series)
> > 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.
> >2 Add more debug/stat info
> > (Partly done, patch is not include into this series)
> > include checkpoint count, proxy discompare count, downtime,
> > number of live migrated pages, total sent pages, etc.
> >3 Strengthen failover
> >4 optimize proxy part, include proxy script.
> >5 The capability of continuous FT
> >
> >v4:
> >- New block replication scheme (use image-fleecing for sencondary side)
> >- Adress some comments from Eric Blake and Dave
> >- Add commmand colo-set-checkpoint-period to set the time of periodic
> >checkpoint
> >- Add a delay (100ms) between continuous checkpoint requests to ensure VM
> > run 100ms at least since last pause.
> >
> >v3:
> >- use proxy instead of colo agent to compare network packets
> >- add block replication
> >- Optimize failover disposal
> >- handle shutdown
> >
> >v2:
> >- use QEMUSizedBuffer/QEMUFile as COLO buffer
> >- colo support is enabled by default
> >- add nic replication support
> >- addressed comments from Eric Blake and Dr. David Alan Gilbert
> >
> >v1:
> >- implement the frame of colo
> >
> >Wen Congyang (1):
> > COLO: Add block replication into colo process
> >
> >zhanghailiang (27):
> > configure: Add parameter for configure to enable/disable COLO support
> > migration: Introduce capability 'colo' to migration
> > COLO: migrate colo related info to slave
> > 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: Implement COLO master/slave failover work
> > COLO failover: Don't do failover during loading VM's state
> > COLO: Add new command parameter 'colo_nicname' 'colo_script' for net
> > COLO NIC: Init/remove colo nic devices when add/cleanup tap devices
> > COLO NIC: Implement colo nic device interface configure()
> > COLO NIC : Implement colo nic init/destroy function
> > COLO NIC: Some init work related with proxy module
> > COLO: Do checkpoint according to the result of net packets comparing
> > COLO: Improve checkpoint efficiency by do additional periodic
> > checkpoint
> > COLO: Add colo-set-checkpoint-period command
> > COLO NIC: Implement NIC checkpoint and failover
> > COLO: Disable qdev hotplug when VM is in COLO mode
> > COLO: Implement shutdown checkpoint
> >
> > arch_init.c | 199 +++++++-
> > configure | 14 +
> > hmp-commands.hx | 30 ++
> > hmp.c | 14 +
> > hmp.h | 2 +
> > include/exec/cpu-all.h | 1 +
> > include/migration/migration-colo.h | 58 +++
> > include/migration/migration-failover.h | 22 +
> > include/migration/migration.h | 3 +
> > include/migration/qemu-file.h | 3 +-
> > include/net/colo-nic.h | 25 +
> > include/net/net.h | 4 +
> > include/sysemu/sysemu.h | 3 +
> > migration/Makefile.objs | 2 +
> > migration/colo-comm.c | 80 ++++
> > migration/colo-failover.c | 48 ++
> > migration/colo.c | 809
> > +++++++++++++++++++++++++++++++++
> > migration/migration.c | 60 ++-
> > migration/qemu-file-buf.c | 58 +++
> > net/Makefile.objs | 1 +
> > net/colo-nic.c | 438 ++++++++++++++++++
> > net/tap.c | 45 +-
> > qapi-schema.json | 42 +-
> > qemu-options.hx | 10 +-
> > qmp-commands.hx | 41 ++
> > savevm.c | 2 +-
> > scripts/colo-proxy-script.sh | 97 ++++
> > stubs/Makefile.objs | 1 +
> > stubs/migration-colo.c | 58 +++
> > vl.c | 36 +-
> > 30 files changed, 2178 insertions(+), 28 deletions(-)
> > create mode 100644 include/migration/migration-colo.h
> > create mode 100644 include/migration/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 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
> >
>
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK