[v3,md-6.15,00/11] md/md-bitmap: introduce CONFIG_MD_BITMAP

Message

Yu Kuai Jan. 23, 2025, 2:07 a.m. UTC

From: Yu Kuai <[e-mail]>

Changes in v2:
 - don't export apis, and don't support build md-bitmap as module
Changes in v3:
 - update commit message.

Due to known performance issues with md-bitmap and the unreasonable
implementations like following:

 - self-managed pages, bitmap_storage->filemap;
 - self-managed IO submitting like filemap_write_page();
 - global spin_lock
 ...

I have decided not to continue optimizing based on the current bitmap
implementation, and plan to invent a new lock-less bitmap. And a new
kconfig option is a good way for isolation. However, we still
encourage anyone who wants to continue optimizing the current
implementation, the new bitmap will take some time to be ready.

Yu Kuai (11):
  md/md-bitmap: remove the parameter 'init' for bitmap_ops->resize()
  md/md-bitmap: merge md_bitmap_group into bitmap_operations
  md/md-bitmap: add md_bitmap_registered/enabled() helper
  md/md-bitmap: handle the case bitmap is not enabled before
    start_sync()
  md/md-bitmap: handle the case bitmap is not enabled before end_sync()
  md/raid1: check bitmap before behind write
  md/raid1: check before deferencing mddev->bitmap_ops
  md/raid10: check before deferencing mddev->bitmap_ops
  md/raid5: check before deferencing mddev->bitmap_ops
  md: check before deferencing mddev->bitmap_ops
  md/md-bitmap: introduce CONFIG_MD_BITMAP

 drivers/md/Kconfig      |  18 +++++
 drivers/md/dm-raid.c    |   2 +-
 drivers/md/md-bitmap.c  |  65 ++++++++---------
 drivers/md/md-bitmap.h  |  66 +++++++++++++++--
 drivers/md/md-cluster.c |   2 +-
 drivers/md/md.c         | 154 +++++++++++++++++++++++++++++++---------
 drivers/md/md.h         |   2 -
 drivers/md/raid1-10.c   |   2 +-
 drivers/md/raid1.c      |  79 ++++++++++++---------
 drivers/md/raid10.c     |  48 ++++++-------
 drivers/md/raid5.c      |  30 ++++----
 11 files changed, 322 insertions(+), 146 deletions(-)