[PATCH v1 0/1] COLO: migrate dirty ram pages before colo checkpoint

[Derek Su]

This series is to reduce the guest's downtime during colo checkpoint
by migrating dirty ram pages as many as possible before colo checkpoint.

If the iteration count reaches COLO_RAM_MIGRATE_ITERATION_MAX or
ram pending size is lower than 'x-colo-migrate-ram-threshold',
stop the ram migration and do colo checkpoint.

Test environment:
The both primary VM and secondary VM has 1GiB ram and 10GbE NIC
for FT traffic.
One fio buffer write job runs on the guest.                                     
                                                                                
The result shows the total primary VM downtime is decreased by ~40%.

Please help to review it and suggestions are welcomed.
Thanks.

Derek Su (1):
  migration/colo.c: migrate dirty ram pages before colo checkpoint

 migration/colo.c       | 79 ++++++++++++++++++++++++++++++++++++++++++
 migration/migration.c  | 20 +++++++++++
 migration/trace-events |  2 ++
 monitor/hmp-cmds.c     |  8 +++++
 qapi/migration.json    | 18 ++++++++--
 5 files changed, 125 insertions(+), 2 deletions(-)

-- 
2.17.1