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From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: Yury Norov <yury.norov@gmail.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-m68k <linux-m68k@lists.linux-m68k.org>,
	Linux-Arch <linux-arch@vger.kernel.org>,
	Linux-SH <linux-sh@vger.kernel.org>,
	Alexey Klimov <aklimov@redhat.com>,
	Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
	Arnd Bergmann <arnd@arndb.de>, David Sterba <dsterba@suse.com>,
	Dennis Zhou <dennis@kernel.org>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Jianpeng Ma <jianpeng.ma@intel.com>,
	Joe Perches <joe@perches.com>,
	John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Rich Felker <dalias@libc.org>,
	Stefano Brivio <sbrivio@redhat.com>,
	Wei Yang <richard.weiyang@linux.alibaba.com>,
	Wolfram Sang <wsa+renesas@sang-engineering.com>,
	Yoshinori Sato <ysato@users.sourceforge.jp>
Subject: Re: [PATCH v6 00/12] lib/find_bit: fast path for small bitmaps
Date: Thu, 1 Apr 2021 12:14:12 +0300	[thread overview]
Message-ID: <CAHp75VdzRXPsQ7Jvivm5UU+mfkgQ_0rmnegp04v-v9fwrjdrqg@mail.gmail.com> (raw)
In-Reply-To: <20210401003153.97325-1-yury.norov@gmail.com>

On Thu, Apr 1, 2021 at 3:36 AM Yury Norov <yury.norov@gmail.com> 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@gmail.com/
> v5: https://lore.kernel.org/linux-arch/20210321215457.588554-1-yury.norov@gmail.com/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

  parent reply	other threads:[~2021-04-01  9:15 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-01  0:31 [PATCH v6 00/12] lib/find_bit: fast path for small bitmaps Yury Norov
2021-04-01  0:31 ` [PATCH 01/12] tools: disable -Wno-type-limits Yury Norov
2021-04-01  0:31 ` [PATCH 02/12] tools: bitmap: sync function declarations with the kernel Yury Norov
2021-04-01  0:31 ` [PATCH 03/12] tools: sync BITMAP_LAST_WORD_MASK() macro " Yury Norov
2021-04-01  0:31 ` [PATCH 04/12] arch: rearrange headers inclusion order in asm/bitops for m68k and sh Yury Norov
2021-04-01  0:31 ` [PATCH 05/12] lib: extend the scope of small_const_nbits() macro Yury Norov
2021-04-01  8:35   ` Andy Shevchenko
2021-04-01  0:31 ` [PATCH 06/12] tools: sync small_const_nbits() macro with the kernel Yury Norov
2021-04-01  0:31 ` [PATCH 07/12] lib: inline _find_next_bit() wrappers Yury Norov
2021-04-01  8:37   ` Andy Shevchenko
2021-04-01  0:31 ` [PATCH 08/12] tools: sync find_next_bit implementation Yury Norov
2021-04-01  0:31 ` [PATCH 09/12] lib: add fast path for find_next_*_bit() Yury Norov
2021-04-01  8:48   ` Andy Shevchenko
2021-04-01  0:31 ` [PATCH 10/12] lib: add fast path for find_first_*_bit() and find_last_bit() Yury Norov
2021-04-01  8:58   ` Andy Shevchenko
2021-04-01  0:31 ` [PATCH 11/12] tools: sync lib/find_bit implementation Yury Norov
2021-05-10 15:27   ` Tetsuo Handa
2021-05-10 15:44     ` Andy Shevchenko
2021-05-10 17:21       ` Yury Norov
2021-05-10 22:51       ` Rikard Falkeborn
2021-05-11  7:28         ` Andy Shevchenko
2021-05-11 10:36           ` Rikard Falkeborn
2021-05-11 11:53             ` Tetsuo Handa
2021-05-11 20:37               ` Rikard Falkeborn
2021-05-12  7:48                 ` Arnd Bergmann
2021-05-12  8:15                   ` Rasmus Villemoes
2021-05-12  8:33                     ` Arnd Bergmann
2021-05-11 12:17             ` Andy Shevchenko
2021-04-01  0:31 ` [PATCH 12/12] MAINTAINERS: Add entry for the bitmap API Yury Norov
2021-04-01  9:14 ` Andy Shevchenko [this message]
2021-04-01  9:28   ` [PATCH v6 00/12] lib/find_bit: fast path for small bitmaps Arnd Bergmann
2021-04-01  9:50     ` Andy Shevchenko
2021-04-02  0:32       ` Andrew Morton

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