[Qemu-devel] [PATCH v10 0/2] mirror: Improve zero write and discard

[Fam Zheng]

v10: Fix and simplify mirror_cow_align. [Max]

v9: Fix the one bug Max found:
    "shrink *= chunk_sectors".

v8: Rebase onto master (didn't pick up Max's rev-by due to non-trivial code
    change).

    The conflict is around removed lines about "max_iov" and "IOV_MAX" due to
    commit 3515727f3, but this also reveals this series forgot that check. So
    this revision adds it back:
    - Two new fields in MirrorBlockJob are added to cache size info:
      target_cluster_sectors and max_iov.
    - mirror_align_cow compares nb_chunks and max_iov, and cut the tail
      appropriately.
    - The orphan trace point is removed from trace-events.

Patch 1 rewrites mirror_iteration. Patch 2 is a small DRY cleaning up.

The main benefit is copying unallocated sectors (both zeroed and discarded)
doesn't go through the iov setup loop, as they don't need it.


Fam Zheng (2):
  mirror: Rewrite mirror_iteration
  mirror: Add mirror_wait_for_io

 block/mirror.c             | 351 +++++++++++++++++++++++++++------------------
 tests/qemu-iotests/109.out |  80 +++++------
 trace-events               |   1 -
 3 files changed, 251 insertions(+), 181 deletions(-)

-- 
2.4.3