[Qemu-devel] [PATCH 00/12] Split ram_save_live() function

[Juan Quintela]

Hi

We have foo_save_live() functions that did 4 things depending on stage
parameter:
* -1: cancel
* 1: setup phase
* 2: iterate live phase
* 3: complete phase

So this series split this functions in 4 functions, one for each phase.
We start just moving code, i.e. not doing any change.

Once we do that, we do some optimization:

- create is_active() method.  We were sending _always_ in each
  iteration information about block migration, even when that sections
  were empty.  This fix that (micro optimization, but makes much
  easier to look at traces)
- for ram, we move the loops to something reasonable:
  * setup: no pages sent (we used to send here)
  * iterate: pages sent as usual
  * complete: instead of sending pages in 2 loops, we send in a single loop.

- Optimization: the previous to last patch is an optimization that
  existed on qemu-kvm tree before I started handling it.  For huge
  memory machines, it makes no sense to synchonize the bitmap each
  time that we enter the iterate function, we only synchronize it when
  we have few dirty pages.

This patches apply on top of the pull request that I just sent to the
list.  You can get it also from my qemu repository:

The following changes since commit a6b61e393908b0d7110d9fab9bfda7b12457bc80:

  Maintain the number of dirty pages (2012-06-28 15:34:37 +0200)

are available in the git repository at:

  http://repo.or.cz/r/qemu/quintela.git save_live_refactorig

for you to fetch changes up to ab1ca756b1cfe67df94f7c6674ea86f6d7232a2f:

  ram: save_live_setup() we don't need to synchronize the dirty bitmap. 
(2012-06-28 20:51:58 +0200)

----------------------------------------------------------------
Juan Quintela (12):
      savevm: Use a struct to pass all handlers
      savevm: Live migration handlers register the struct directly
      savevm: remove SaveSetParamsHandler
      savevm: remove SaveLiveStateHandler
      savevm: Refactor cancel operation in its own operation
      savevm: introduce is_active method
      savevm: split save_live_setup from save_live_state
      savevm: split save_live into stage2 and stage3
      ram: save_live_setup() don't need to sent pages
      ram: save_live_complete() only do one loop
      ram: iterate phase
      ram: save_live_setup() we don't need to synchronize the dirty bitmap.

 arch_init.c       |  118 ++++++++++++++++++++++++-----------------
 block-migration.c |  153 +++++++++++++++++++++++++++++++++++------------------
 migration.h       |    4 +-
 savevm.c          |   77 +++++++++++++++------------
 vl.c              |    3 +-
 vmstate.h         |   18 ++++---
 6 files changed, 228 insertions(+), 145 deletions(-)


Please review.

Juan Quintela (12):
  savevm: Use a struct to pass all handlers
  savevm: Live migration handlers register the struct directly
  savevm: remove SaveSetParamsHandler
  savevm: remove SaveLiveStateHandler
  savevm: Refactor cancel operation in its own operation
  savevm: introduce is_active method
  savevm: split save_live_setup from save_live_state
  savevm: split save_live into stage2 and stage3
  ram: save_live_setup() don't need to sent pages
  ram: save_live_complete() only do one loop
  ram: iterate phase
  ram: save_live_setup() we don't need to synchronize the dirty bitmap.

 arch_init.c       |  118 ++++++++++++++++++++++++-----------------
 block-migration.c |  153 +++++++++++++++++++++++++++++++++++------------------
 migration.h       |    4 +-
 savevm.c          |   77 +++++++++++++++------------
 vl.c              |    3 +-
 vmstate.h         |   18 ++++---
 6 files changed, 228 insertions(+), 145 deletions(-)

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1.7.10.2