[Qemu-devel] [PATCH RFC v3 00/14] Dirty bitmaps migration

[Vladimir Sementsov-Ogievskiy]

v3:
 based on v13 of "block: incremental backup series" by John Snow.

 changes from v2:
 removed patch for adding dirty parameter (migration capablities used
 instead).
 
 0001: printf's dropped, qapi used
 0002: part0 -> zeroes
 0003: part0 -> zeroes
 0005: dirty_dirty -> meta
       add comments about meta bitmap
       
 0006: the format is changed, nodes used instead of devices.

 other patches are new.

 rfc: there are two tests. They are the same but using different
 interfaces: md5 checksum of the bitmap last layer in query-block or
 separate query-block-dirty-bitmap with dirty bitmap regions.
 The second form is more appropriate for debugging, the first is more
 appropriate for simple regression control. Which should go to
 upstream?

v2:
 1. bug-fixes, that are already in upstream, and renaming of function
 bdrv_reset_dirty_bitmap (which is already in Snow's series) are
 dropped
 2. bitmap store/restore: the concept renamed to serialization, added
 function hbitmap_deserialize_part0, to not transfer zero blocks
 3. migration dirty parameter: added description comment
 4. Other patches are new.

v2.rfc:
Actually, in this version of the series I'm trying not use
migration/block.c at all. Instead a separate migration unit is added
in the new file migration/dirty-bitmap.c. Now bitmaps are migrated
like blocks in block migration, they have their "dirty-dirty" bitmaps,
for tracking set/unset changes during migration.

The advantages are:
  - no complications of migration/block.c
  - separate dirty-dirty bitmaps provide handling of "unset's"
  - more effective meta-data/data ratio - no tiny bitmap-blocks.



v1:
These patches provide dirty bitmap migration feature. Only named dirty
bitmaps are to be migrated. Migration is made as a part of block
migration in block-migration.c.

Dirty bitmap migration may be enabled by "dirty" parameter for qmp migrate
command. If "blk" and "inc" parameters are false when "dirty" is true
block migration is actually skipped: no allocatoions, no bdrv_read's,
no bdrv_write's, only bitmaps are migrated.

The patch set includes two my previous bug fixes, which are necessary
for it. The patch set is based on Incremental backup series by John
Snow.

Vladimir Sementsov-Ogievskiy (14):
  qmp: add query-block-dirty-bitmap
  hbitmap: serialization
  block: BdrvDirtyBitmap serialization interface
  block: tiny refactoring: minimize hbitmap_(set/reset) usage
  block: add meta bitmaps
  block: add bdrv_next_dirty_bitmap()
  qapi: add dirty-bitmaps migration capability
  migration: add migration/block-dirty-bitmap.c
  iotests: maintain several vms in test
  iotests: add add_incoming_migration to VM class
  iotests: add dirty bitmap migration test
  qapi: add md5 checksum of last dirty bitmap level to query-block
  iotests: add dirty bitmap migration test
  migration/qemu-file: make functions qemu_(get/put)_string public

 block.c                        | 135 ++++++++-
 blockdev.c                     |  24 ++
 hmp-commands.hx                |   2 +
 hmp.c                          |  32 ++
 hmp.h                          |   1 +
 include/block/block.h          |  22 ++
 include/migration/block.h      |   1 +
 include/migration/migration.h  |   1 +
 include/migration/qemu-file.h  |  17 ++
 include/qemu/hbitmap.h         |  67 ++++
 migration/Makefile.objs        |   2 +-
 migration/block-dirty-bitmap.c | 673 +++++++++++++++++++++++++++++++++++++++++
 migration/migration.c          |   9 +
 migration/qemu-file.c          |  18 ++
 monitor.c                      |   7 +
 qapi-schema.json               |   5 +-
 qapi/block-core.json           |  79 ++++-
 qmp-commands.hx                |   5 +
 tests/qemu-iotests/117         |  88 ++++++
 tests/qemu-iotests/117.out     |   5 +
 tests/qemu-iotests/118         |  87 ++++++
 tests/qemu-iotests/118.out     |   5 +
 tests/qemu-iotests/group       |   2 +
 tests/qemu-iotests/iotests.py  |  12 +-
 util/hbitmap.c                 | 104 +++++++
 vl.c                           |   1 +
 26 files changed, 1395 insertions(+), 9 deletions(-)
 create mode 100644 migration/block-dirty-bitmap.c
 create mode 100755 tests/qemu-iotests/117
 create mode 100644 tests/qemu-iotests/117.out
 create mode 100755 tests/qemu-iotests/118
 create mode 100644 tests/qemu-iotests/118.out

-- 
1.9.1