Bitmap operations are much simpler and faster in case of small bitmaps, whicn
fit into a single word. In linux/bitmap.h we have a machinery that allows
compiler to replace actual function call with a few instructions if bitmaps
passed into the function is small and its size is known at compile time.
find_*_bit() API lacks this functionality; despite users will benefit from it
a lot. One important example is cpumask subsystem, when NR_CPUS <= BITS_PER_LONG.
In the very best case, the compiler may replace a find_*_bit() call for such a
bitmap with a single ffs or ffz instruction.
Tools is synchronized with new implementation where needed.
Yury Norov (6):
arch: rearrange headers inclusion order in asm/bitops for m68k and sh
lib: inttroduce BITS_{FIRST,LAST}() macro
bits_per_long.h: introduce SMALL_CONST() macro
lib: inline _find_next_bit() wrappers
lib: add fast path for find_next_*_bit()
lib: add fast path for find_first_*_bit() and find_last_bit()
arch/m68k/include/asm/bitops.h | 4 +-
arch/sh/include/asm/bitops.h | 3 +-
include/asm-generic/bitops/find.h | 108 +++++++++++++++++++++---
include/asm-generic/bitops/le.h | 38 ++++++++-
include/asm-generic/bitsperlong.h | 2 +
include/linux/bitmap.h | 60 ++++++-------
include/linux/bitops.h | 12 ---
include/linux/bits.h | 6 ++
include/linux/cpumask.h | 8 +-
include/linux/netdev_features.h | 2 +-
include/linux/nodemask.h | 2 +-
lib/bitmap.c | 26 +++---
lib/find_bit.c | 72 +++-------------
lib/genalloc.c | 8 +-
tools/include/asm-generic/bitops/find.h | 85 +++++++++++++++++--
tools/include/asm-generic/bitsperlong.h | 2 +
tools/include/linux/bitmap.h | 39 +++------
tools/include/linux/bits.h | 6 ++
tools/lib/bitmap.c | 6 +-
tools/lib/find_bit.c | 56 +++++-------
tools/testing/radix-tree/bitmap.c | 4 +-
21 files changed, 330 insertions(+), 219 deletions(-)
--
2.25.1
