On 17.08.2016 15:35, Dr. David Alan Gilbert wrote:
* Vladimir Sementsov-Ogievskiy (vsement...@virtuozzo.com) wrote:
v2:
some bugs fixed, iotests a bit changed and merged into one test.
based on block-next (https://github.com/XanClic/qemu/commits/block-next)
clone: tag postcopy-v2 from https://src.openvz.org/scm/~vsementsov/qemu.git
online:
https://src.openvz.org/users/vsementsov/repos/qemu/browse?at=refs%2Ftags%2Fpostcopy-v2
v1:
These series are derived from my 'Dirty bitmaps migration' series. The
core idea is switch to postcopy migration and drop usage of meta
bitmaps.
These patches provide dirty bitmap postcopy migration feature. Only
named dirty bitmaps are to be migrated. Migration may be enabled using
migration capabilities.
The overall method (thanks to John Snow):
1. migrate bitmaps meta data in .save_live_setup
- create/find related bitmaps on target
- disable them
- create successors (anonimous children) only for enabled migrated
bitmaps
2. do nothing in precopy stage
3. just before target vm start: enable successors, created in (1)
4. migrate bitmap data
5. reclaime bitmaps (merge successors to their parents)
6. enable bitmaps (only bitmaps, which was enabled in source)
I'd like to just understand a little bit more about the structure;
a)I don't see anything where the destination asks the source for data;
am I right or just missing that?
You are right
b)If I'm right about (a) is the only reason it's called 'postcopy'
because it's done when the destination is already running?
Yes
c)How does it play together with ram postcopy; do they get in each
others way?
They should work together, but I have no tests for this case yet.
Dave
Some patches are unchnaged from (v7) of 'Dirty bitmaps migration'
(DBMv7). I've left Reviewed-by's for them, if you don't like it, say me
and I'll drop them in the following version.
So, relatively to last DBMv7:
01-04: new patches, splitting common postcopy migration out of ram
postcopy migration
05: equal to DBMv7.05
06: new
07: equal to DBMv7.06
08: new
09: equal to DBMv7.07
10: new
11: derived from DBMv7.08, see below
12-15: equal to DBMv7.09-12
16: derived from DBMv7.13
- switch from fifo to socket, as postcopy don't work with fifo
for now
- change parameters: size, granularity, regions
- add time.sleep, to wait for postcopy migration phase (bad
temporary solution.
- drop Reviewed-by
17: new
11: the core patch of the series, it is derived from
[DBMv7.08: migration: add migration_block-dirty-bitmap.c]
There are a lot of changes related to switching from precopy to
postcopy, but functions related to migration stream itself
(structs, send/load sequences) are mostly unchnaged.
So, changes, to switch from precopy to postcopy:
- removed all staff related to meta bitmaps and dirty phase!!!
- add dirty_bitmap_mig_enable_successors, and call it before
target vm start in loadvm_postcopy_handle_run
- add enabled_bitmaps list of bitmaps for
dirty_bitmap_mig_enable_successors
- enabled flag is send with start bitmap chunk instead of
completion chunk
- sectors_per_chunk is calculated directly from CHUNK_SIZE, not
using meta bitmap granularity
- dirty_bitmap_save_iterate: remove dirty_phase, move bulk_phase
to postcopy stage
- dirty_bitmap_save_pending: remove dirty phase related pending,
switch pending to non-postcopyable
- dirty_bitmap_load_start: get enabled flag and prepare
successors for enabled bitmaps, also add them to
enabled_bitmaps list
- dirty_bitmap_load_complete: for enabled bitmaps: merge them
with successors and enable
- savevm handlers:
* remove separate savevm_dirty_bitmap_live_iterate_handlers state
(it was bad idea, any way), and move its save_live_iterate to
savevm_dirty_bitmap_handlers
* add is_active_iterate savevm handler, which allows iterations
only in postcopy stage (after stopping source vm)
* add has_postcopy savevm handler. (ofcourse, just returning true)
* use save_live_complete_postcopy instead of
save_live_complete_precopy
Other changes:
- some debug output changed
- remove MIN_LIVE_SIZE, is_live_iterative and related staff (it
was needed to omit iterations if bitmap data is small, possibly
this should be reimplemented)
Vladimir Sementsov-Ogievskiy (18):
migration: add has_postcopy savevm handler
migration: fix ram_save_pending
migration: split common postcopy out of ram postcopy
migration: introduce postcopy-only pending
block: add bdrv_next_dirty_bitmap()
block: add bdrv_dirty_bitmap_enable_successor()
qapi: add dirty-bitmaps migration capability
block/dirty-bitmap: add bdrv_dirty_bitmap_release_successor
migration: include migrate_dirty_bitmaps in migrate_postcopy
migration/qemu-file: add qemu_put_counted_string()
migration: add is_active_iterate handler
migration: add postcopy migration of dirty bitmaps
iotests: maintain several vms in test
iotests: add add_incoming_migration to VM class
qapi: add md5 checksum of last dirty bitmap level to query-block
iotests: add default node-name
iotests: add dirty bitmap migration test 117
iotests: add dirty bitmap postcopy test
block/dirty-bitmap.c | 26 ++
include/block/dirty-bitmap.h | 6 +
include/migration/block.h | 1 +
include/migration/migration.h | 6 +
include/migration/qemu-file.h | 2 +
include/migration/vmstate.h | 7 +-
include/qemu/hbitmap.h | 8 +
include/sysemu/sysemu.h | 5 +-
migration/Makefile.objs | 2 +-
migration/block-dirty-bitmap.c | 699 +++++++++++++++++++++++++++++++++++++++++
migration/block.c | 7 +-
migration/migration.c | 66 ++--
migration/postcopy-ram.c | 4 +-
migration/qemu-file.c | 13 +
migration/ram.c | 19 +-
migration/savevm.c | 56 +++-
migration/trace-events | 2 +-
qapi-schema.json | 4 +-
qapi/block-core.json | 5 +-
tests/qemu-iotests/169 | 134 ++++++++
tests/qemu-iotests/169.out | 5 +
tests/qemu-iotests/group | 2 +
tests/qemu-iotests/iotests.py | 21 +-
util/hbitmap.c | 8 +
vl.c | 1 +
25 files changed, 1055 insertions(+), 54 deletions(-)
create mode 100644 migration/block-dirty-bitmap.c
create mode 100755 tests/qemu-iotests/169
create mode 100644 tests/qemu-iotests/169.out
--
1.8.3.1
--
Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK
--
Best regards,
Vladimir