[Qemu-devel] [PATCH RFC v2 0/8] Dirty bitmaps migration

[Vladimir Sementsov-Ogievskiy]

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 (8):
  qmp: print dirty bitmap
  hbitmap: serialization
  block: BdrvDirtyBitmap serialization interface
  block: add dirty-dirty bitmaps
  block: add bdrv_dirty_bitmap_enabled()
  block: add bdrv_next_dirty_bitmap()
  migration: add dirty parameter
  migration: add migration/dirty-bitmap.c

 block.c                       | 128 +++++++++
 blockdev.c                    |  13 +
 hmp-commands.hx               |  27 +-
 hmp.c                         |  12 +-
 hmp.h                         |   1 +
 include/block/block.h         |  22 ++
 include/migration/block.h     |   1 +
 include/migration/migration.h |   1 +
 include/qemu/hbitmap.h        |  59 ++++
 migration/Makefile.objs       |   2 +-
 migration/dirty-bitmap.c      | 606 ++++++++++++++++++++++++++++++++++++++++++
 migration/migration.c         |   4 +-
 qapi-schema.json              |  10 +-
 qapi/block-core.json          |   3 +
 qmp-commands.hx               |  10 +-
 savevm.c                      |   3 +-
 util/hbitmap.c                |  96 +++++++
 vl.c                          |   1 +
 18 files changed, 987 insertions(+), 12 deletions(-)
 create mode 100644 migration/dirty-bitmap.c

-- 
1.9.1