[PATCH v5 00/11] xfs: rework near mode extent allocation

[Brian Foster <bfoster@redhat.com>]

Hi all,

Here's v5 of the near mode block allocation rework. This mostly consists
of various minor cleanups from v4. The only functional change is to
deactivate the cntbt cursor on finding a perfect extent in patch 8.
Thoughts, reviews, flames appreciated.

Brian

v5:
- Fix up active logic in patch 1.
- Fix busy_gen type.
- Change ->diff initialization value in proper patch.
- Deactivate cntbt cursor on location of perfect extent.
- Various aesthetic cleanups. 
v4: https://lore.kernel.org/linux-xfs/20190916121635.43148-1-bfoster@redhat.com/
- Fix up cursor active tracking type usage.
- Fix up cntbt lookup function signature.
- Added high level comment on optimized allocation algorithm.
- Split up series into smaller patches to separate refactoring from
  functional changes.
v3: https://lore.kernel.org/linux-xfs/20190815125538.49570-1-bfoster@redhat.com/
- Drop by-size and exact allocation rework bits.
- Add near mode last block scan.
- Add debug mode patch to randomly toggle near mode algos.
- Refactor cursor setup/lookup logic.
- Refactor minlen reverse scan to be common between near mode algos.
- Fix up logic to consistently prioritize extent size over locality.
- Add more useful tracepoints.
- Miscellaneous bug fixes and code/comment cleanups.
v2: https://marc.info/?l=linux-xfs&m=155854834815400&w=2
- Lift small mode refactoring into separate patch (retained review
  tag(s).
- Various logic cleanups and refactors.
- Push active flag down into btree cursor private area; eliminate cursor
  container struct.
- Refactor final allocation code. Fold xfs_alloc_ag_vextent_type() into
  caller and factor out accounting.                                                                                                                     
- Fix up tracepoints.
v1: https://marc.info/?l=linux-xfs&m=155742169729590&w=2
- Continued development (various fixes, refinements) on generic bits and
  near mode implementation.
- Added patches 4-6 to refactor exact, by-size and small allocation
  modes.
rfcv2: https://marc.info/?l=linux-xfs&m=155197946630582&w=2
- Dropped spurious initial refactoring.
- Added minlen functionality.
- Properly tied into near alloc path.
- General refactoring and cleanups.
rfcv1: https://marc.info/?l=linux-xfs&m=154479089914351&w=2

Brian Foster (11):
  xfs: track active state of allocation btree cursors
  xfs: introduce allocation cursor data structure
  xfs: track allocation busy state in allocation cursor
  xfs: track best extent from cntbt lastblock scan in alloc cursor
  xfs: refactor cntbt lastblock scan best extent logic into helper
  xfs: reuse best extent tracking logic for bnobt scan
  xfs: refactor allocation tree fixup code
  xfs: refactor and reuse best extent scanning logic
  xfs: refactor near mode alloc bnobt scan into separate function
  xfs: factor out tree fixup logic into helper
  xfs: optimize near mode bnobt scans with concurrent cntbt lookups

 fs/xfs/libxfs/xfs_alloc.c       | 897 ++++++++++++++++++--------------
 fs/xfs/libxfs/xfs_alloc_btree.c |   1 +
 fs/xfs/libxfs/xfs_btree.h       |   3 +
 fs/xfs/xfs_trace.h              |  33 +-
 4 files changed, 547 insertions(+), 387 deletions(-)

-- 
2.20.1