On Thu, Apr 1, 2021 at 3:36 AM Yury Norov <yury.norov@xxxxxxxxx> wrote: > > Bitmap operations are much simpler and faster in case of small bitmaps > which fit into a single word. In linux/bitmap.c 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; but users will benefit from it > a lot. One important example is cpumask subsystem when > NR_CPUS <= BITS_PER_LONG. Cool, thanks! I guess it's assumed to go via Andrew's tree. But after that since you are about to be a maintainer of this, I think it would make sense to send PRs directly to Linus. I would recommend creating an official tree (followed by an update in the MAINTAINERS) and connecting it to Linux next (usually done by email to Stephen). > v6 is mostly a resend. The only change comparing to v5 is a fix of > small_const_nbits() synchronization patch. > > v1: https://www.spinics.net/lists/kernel/msg3804727.html > v2: https://www.spinics.net/lists/linux-m68k/msg16945.html > v3: https://www.spinics.net/lists/kernel/msg3837020.html > v4: https://patchwork.kernel.org/project/linux-sh/cover/20210316015424.1999082-1-yury.norov@xxxxxxxxx/ > v5: https://lore.kernel.org/linux-arch/20210321215457.588554-1-yury.norov@xxxxxxxxx/T/ > v6: - sync small_const_nbits() properly (patch 6). > - Rasmus' ack added. > > Yury Norov (12): > tools: disable -Wno-type-limits > tools: bitmap: sync function declarations with the kernel > tools: sync BITMAP_LAST_WORD_MASK() macro with the kernel > arch: rearrange headers inclusion order in asm/bitops for m68k and sh > lib: extend the scope of small_const_nbits() macro > tools: sync small_const_nbits() macro with the kernel > lib: inline _find_next_bit() wrappers > tools: sync find_next_bit implementation > lib: add fast path for find_next_*_bit() > lib: add fast path for find_first_*_bit() and find_last_bit() > tools: sync lib/find_bit implementation > MAINTAINERS: Add entry for the bitmap API > > MAINTAINERS | 16 ++++ > arch/m68k/include/asm/bitops.h | 6 +- > arch/sh/include/asm/bitops.h | 5 +- > include/asm-generic/bitops/find.h | 108 +++++++++++++++++++++--- > include/asm-generic/bitops/le.h | 38 ++++++++- > include/asm-generic/bitsperlong.h | 12 +++ > include/linux/bitmap.h | 8 -- > include/linux/bitops.h | 12 --- > lib/find_bit.c | 68 ++------------- > tools/include/asm-generic/bitops/find.h | 85 +++++++++++++++++-- > tools/include/asm-generic/bitsperlong.h | 3 + > tools/include/linux/bitmap.h | 18 ++-- > tools/lib/bitmap.c | 4 +- > tools/lib/find_bit.c | 56 +++++------- > tools/scripts/Makefile.include | 1 + > 15 files changed, 284 insertions(+), 156 deletions(-) > > -- > 2.25.1 > -- With Best Regards, Andy Shevchenko
