[PATCH RFC -next 00/26] md/md-bitmap: introduce bitmap_operations

[Yu Kuai]

From: Yu Kuai <yukuai3@xxxxxxxxxx>

The background is that currently bitmap is using a global spin_lock,
cauing lock contention and huge IO performance degration for all raid
levels.

However, it's impossible to implement a new lock free bitmap with
current situation that md-bitmap exposes the internal implementation
with lots of exported apis. Hence bitmap_operations is invented, to
describe bitmap core implementation, and a new bitmap can be introduced
with a new bitmap_operations, we only need to switch to the new one
during initialization.

And with this we can build bitmap as kernel module, but that's not
our concern for now.

Noted I just compile this patchset, not tested yet.

Yu Kuai (26):
  md/md-bitmap: introduce struct bitmap_operations
  md/md-bitmap: merge md_bitmap_create() into bitmap_operations
  md/md-bitmap: merge md_bitmap_load() into bitmap_operations
  md/md-bitmap: merge md_bitmap_destroy() into bitmap_operations
  md/md-bitmap: merge md_bitmap_flush() into bitmap_operations
  md/md-bitmap: don't expose md_bitmap_print_sb()
  md/md-bitmap: merge md_bitmap_update_sb() into bitmap_operations
  md/md-bitmap: merge md_bitmap_status() into bitmap_operations
  md/md-bitmap: remove md_bitmap_setallbits()
  md/md-bitmap: merge bitmap_write_all() into bitmap_operations
  md/md-bitmap: merge md_bitmap_dirty_bits() into bitmap_operations
  md/md-bitmap: merge md_bitmap_startwrite() into bitmap_operations
  md/md-bitmap: merge md_bitmap_endwrite() into bitmap_operations
  md/md-bitmap: merge md_bitmap_start_sync() into bitmap_operations
  md/md-bitmap: merge md_bitmap_end_sync() into bitmap_operations
  md/md-bitmap: merge md_bitmap_close_sync() into bitmap_operations
  md/md-bitmap: mrege md_bitmap_cond_end_sync() into bitmap_operations
  md/md-bitmap: merge bitmap_sync_with_cluster() into bitmap_operations
  md/md-bitmap: merge md_bitmap_resize() into bitmap_operations
  md/md-bitmap: merge get_bitmap_from_slot() into bitmap_operations
  md/md-bitmap: merge md_bitmap_copy_from_slot() into bitmap_operations
  md/md-bitmap: merge md_bitmap_free() into bitmap_operations
  md/md-bitmap: merge md_bitmap_wait_behind_writes() into
    bitmap_operations
  md/md-bitmap: merge md_bitmap_daemon_work() into bitmap_operations
  md/md-bitmap: merge md_bitmap_unplug() and md_bitmap_unplug_async()
  md/md-bitmap: merge bitmap_unplug() into bitmap_operations

 drivers/md/dm-raid.c     |   2 +-
 drivers/md/md-bitmap.c   | 216 +++++++++++++++++---------------
 drivers/md/md-bitmap.h   | 259 ++++++++++++++++++++++++++++++++++-----
 drivers/md/md-cluster.c  |  21 ++--
 drivers/md/md.c          |  13 +-
 drivers/md/md.h          |   1 +
 drivers/md/raid1-10.c    |   7 +-
 drivers/md/raid1.c       |  22 ++--
 drivers/md/raid10.c      |  32 +++--
 drivers/md/raid5-cache.c |   2 +-
 drivers/md/raid5.c       |  25 ++--
 11 files changed, 401 insertions(+), 199 deletions(-)

-- 
2.39.2