linux-kernel - [PATCH 00/12] bitmap: rework bitmap

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Message-Id: <20230828184353.5145-1-yury.norov@gmail.com>
Date:   Mon, 28 Aug 2023 11:43:40 -0700
From:   Yury Norov <yury.norov@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     Yury Norov <yury.norov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>
Subject: [PATCH 00/12] bitmap: rework bitmap_{bit,}remap()

This series adds a test, const-time optimizaton and fixes O(N^2)
complexity problem for the functions. It's based on discussion in
bitmap: optimize bitmap_remap() series [1], but there's much more work
here, so I decided to give it a separete run, and don't name it as v2.

bitmap_remap() API has just one user in generic code, and few more in
drivers, so this may look like an overkill. But the work gives ~10x
better performance for a 1000-bit bitmaps, which is typical for nodemasks
in major distros like Ubuntu.

Anyways, the work is done, so guys please review.

[1] https://lore.kernel.org/lkml/20230815235934.47782-1-yury.norov@gmail.com/T/
Yury Norov (12):
  bitmap: add find_nth_bit_from()
  bitmap: add bitmap_weight_from()
  bitmap: add test for bitmap_remap()
  bitmap: add test for bitmap_bitremap()
  bitmap: update comment for bitmap_{bit,}remap()
  bitmap: add small_cont_nbits() optimization for bitmap_remap()
  bitmap: add small_const_nbits() optimization for bitmap_bitremap()
  bitmap: optiimze bitmap_bitremap()
  bitmap: optimize bitmap_remap() when 'new' is empty map
  bitmap: separate handling of identity and remapping parts in
    bitmap_remap()
  bitmap: defer calculating weight of 'new' in bitmap_remap()
  bitmap: don't count bits from the beginning in bitmap_remap()

 include/linux/bitmap.h | 116 +++++++++++++++++++++++++++++++--
 include/linux/find.h   |  37 +++++++++++
 lib/bitmap.c           | 145 ++++++++++++++++++++---------------------
 lib/find_bit.c         |  29 +++++++++
 lib/test_bitmap.c      | 142 +++++++++++++++++++++++++++++++++++++++-
 5 files changed, 388 insertions(+), 81 deletions(-)

-- 
2.39.2