[v3,0/4] btrfs: data block group size classes

Message

Boris Burkov Nov. 18, 2022, 6:27 p.m. UTC

This patch set introduces the notion of size classes to the block group
allocator for data block groups. This is specifically useful because the
first fit allocator tends to perform poorly when large extents free up
in older block groups and small writes suddenly shift there. Generally,
it should lead to slightly more predictable allocator behavior as the
gaps left by frees will be used by allocations of a similar size.

Details about the changes and performance testing are in the individual
commit messages.

The last two patches constitute the business of the change. One adds the
size classes and the other handles the fact that we don't want to
persist the size class, so we don't know it when we first load a block
group.
---
v3:
- fix double newline in extent-tree.h
- fix ctree.h include in extent-tree.h refactor
v2:
- removed 1G falloc extents patch
- rebased tracepoints patches onto significant header file refactor

Boris Burkov (4):
  btrfs: use ffe_ctl in btrfs allocator tracepoints
  btrfs: add more ffe tracepoints
  btrfs: introduce size class to block group allocator
  btrfs: load block group size class when caching

 fs/btrfs/block-group.c       | 234 ++++++++++++++++++++++++++++++++---
 fs/btrfs/block-group.h       |  15 ++-
 fs/btrfs/extent-tree.c       | 167 +++++++------------------
 fs/btrfs/extent-tree.h       |  81 ++++++++++++
 fs/btrfs/super.c             |   1 +
 include/trace/events/btrfs.h | 128 +++++++++++++++----
 6 files changed, 467 insertions(+), 159 deletions(-)