[PATCH RFC -next v2 00/41] md/md-bitmap: introduce bitmap_operations and make structure internel

Yu Kuai
2024-08-14T07:15:28Z

Changes in v2:
- add patch 1-8 to prevent dereference bitmap directly, and the last
patch to make bitmap structure internel.
- use plain function alls "bitmap_ops->xxx()" directly;

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 (41):
md/raid1: use md_bitmap_wait_behind_writes() in raid1_read_request()
md/md-bitmap: replace md_bitmap_status() with a new helper
md_bitmap_get_stats()
md: use new helper md_bitmap_get_stats() in update_array_info()
md/md-bitmap: add 'events_cleared' into struct md_bitmap_stats
md/md-bitmap: add 'sync_size' into struct md_bitmap_stats
md/md-bitmap: add 'file_pages' into struct md_bitmap_stats
md/md-bitmap: add 'behind_writes' and 'behind_wait' into struct
md_bitmap_stats
md/md-cluster: use helper md_bitmap_get_stats() to get pages in
resize_bitmaps()
md/md-bitmap: add a new helper md_bitmap_set_pages()
md/md-bitmap: introduce struct bitmap_operations
md/md-bitmap: simplify md_bitmap_create() + md_bitmap_load()
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: make md_bitmap_print_sb() internal
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: remove the parameter 'aborted' for md_bitmap_end_sync()
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 md_bitmap_sync_with_cluster() into
bitmap_operations
md/md-bitmap: merge md_bitmap_unplug_async() into md_bitmap_unplug()
md/md-bitmap: merge bitmap_unplug() into bitmap_operations
md/md-bitmap: merge md_bitmap_daemon_work() into bitmap_operations
md/md-bitmap: pass in mddev directly for md_bitmap_resize()
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 struct
bitmap_operation.
md/md-bitmap: merge md_bitmap_set_pages() into struct
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_enabled() into bitmap_operations
md/md-bitmap: make in memory structure internal

drivers/md/dm-raid.c | 7 +-
drivers/md/md-bitmap.c | 561 +++++++++++++++++++++++++++++----------
drivers/md/md-bitmap.h | 272 ++++---------------
drivers/md/md-cluster.c | 79 +++---
drivers/md/md.c | 133 ++++++----
drivers/md/md.h | 3 +-
drivers/md/raid1-10.c | 9 +-
drivers/md/raid1.c | 78 +++---
drivers/md/raid10.c | 73 ++---
drivers/md/raid5-cache.c | 8 +-
drivers/md/raid5.c | 62 ++---
11 files changed, 731 insertions(+), 554 deletions(-)

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2.39.2