Bitmap operations are much simpler and faster in case of small bitmaps which 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 are small and their 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. v1: https://www.spinics.net/lists/kernel/msg3804727.html v2: - employ GENMASK() for bitmaps; - unify find_bit inliners in; - address comments to v1; Yury Norov (8): tools: disable -Wno-type-limits tools: bitmap: sync function declarations with linux kernel arch: rearrange headers inclusion order in asm/bitops for m68k and sh lib: introduce BITS_{FIRST,LAST} macro bitsperlong.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 | 47 ++++------- tools/include/linux/bits.h | 6 ++ tools/lib/bitmap.c | 10 +-- tools/lib/find_bit.c | 56 +++++------- tools/scripts/Makefile.include | 1 + tools/testing/radix-tree/bitmap.c | 4 +- 22 files changed, 337 insertions(+), 225 deletions(-) -- 2.25.1
