[PATCH v3 0/7] migration/multifd: Some VFIO / postcopy preparations on flush

[Peter Xu]

CI: https://gitlab.com/peterx/qemu/-/pipelines/1577280033
 (note: it's a pipeline of two patchsets, to save CI credits and time)

v1: 20241205185303.897010-1-peterx@redhat.com">https://lore.kernel.org/r/20241205185303.897010-1-peterx@redhat.com
v2: 20241206005834.1050905-1-peterx@redhat.com">https://lore.kernel.org/r/20241206005834.1050905-1-peterx@redhat.com

v3 changelog:
- R-bs collected
- Update commit message of patch 1 [Fabiano]
- English updates [Fabiano]
- Update comment for MULTIFD_SYNC_ALL [Fabiano]
- In multifd_send_sync_main(), assert on req type [Fabiano]
- Some more comments and cleanup for RAM_SAVE_FLAG_* movement [Fabiano]
- Update the last document patch [Fabiano]

This series provides some changes that may be helpful for either VFIO or
postcopy integration on top of multifd.

For VFIO, only patches 1 & 2 are relevant.

For postcopy, it's about patches 3-7, but it needs to be based on 1+2
because of a context dependency.

All these patches can be seen as cleanups / slight optimizations on top of
master branch with/without the VFIO/postcopy work.

Besides CI, qtests, and some real-world multifd tests just to monitor the
sync events happen all correct, I made sure to cover 7.2 machine type
(which uses the legacy sync) so it still works as before - basically sync
will be more frequent, but all thing keeps working smoothly so far.

Thanks,

Peter Xu (7):
  migration/multifd: Further remove the SYNC on complete
  migration/multifd: Allow to sync with sender threads only
  migration/ram: Move RAM_SAVE_FLAG* into ram.h
  migration/multifd: Unify RAM_SAVE_FLAG_MULTIFD_FLUSH messages
  migration/multifd: Remove sync processing on postcopy
  migration/multifd: Cleanup src flushes on condition check
  migration/multifd: Document the reason to sync for save_setup()

 migration/multifd.h        | 27 ++++++++++--
 migration/ram.h            | 28 ++++++++++++
 migration/rdma.h           |  7 ---
 migration/multifd-nocomp.c | 74 ++++++++++++++++++++++++++++++-
 migration/multifd.c        | 17 +++++---
 migration/ram.c            | 89 +++++++++++++++++---------------------
 6 files changed, 173 insertions(+), 69 deletions(-)

-- 
2.47.0