[PATCH v4 v4 0/3] ext4: improve mballoc statistics reporting and control

[Baolin Liu]

This series improves ext4 mballoc statistics reporting and control.
Compared with v3, this version adds a new patch to convert s_mb_stats
to atomic_t and use atomic operations for its accesses, so as to avoid
potential concurrent accesses to this variable.

Patch 3 is updated according to comments from Ted and BaoKun. Writing 0
to /proc/fs/ext4/<dev>/mb_stats disables statistics collection, writing
1 enables it, and writing -1 clears the current statistics and enables
collection. The related documentation is updated accordingly, and the
sysfs mb_stats entry is documented as deprecated in favor of the proc
mb_stats entry.

Changes since v3:
  - add a new patch to convert s_mb_stats to atomic_t and use atomic
    operations for its accesses
  - update /proc/fs/ext4/<dev>/mb_stats write semantics based on comments
    from Ted and BaoKun
  - update related documentation and document sysfs mb_stats as deprecated

Baolin Liu (3):
  ext4: add blocks_allocated to mb_stats output
  ext4: use atomic operations for s_mb_stats accesses
  ext4: allow controlling mballoc stats through proc mb_stats

 Documentation/ABI/testing/sysfs-fs-ext4 |  3 +-
 Documentation/admin-guide/ext4.rst      |  9 +++-
 Documentation/filesystems/proc.rst      | 13 +-----
 fs/ext4/ext4.h                          |  3 +-
 fs/ext4/mballoc.c                       | 57 +++++++++++++++++++------
 fs/ext4/sysfs.c                         | 55 ++++++++++++++++++++++--
 6 files changed, 109 insertions(+), 31 deletions(-)

-- 
2.51.0