From: Yury Norov <yury.norov@gmail.com>
To: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
linux-arch@vger.kernel.org, linux-sh@vger.kernel.org,
Alexey Klimov <aklimov@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
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>,
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 04/14] lib: introduce BITS_{FIRST,LAST} macro
Date: Thu, 11 Mar 2021 20:30:57 -0800 [thread overview]
Message-ID: <20210312043057.GA137474@yury-ThinkPad> (raw)
In-Reply-To: <b371c94c-7480-5af4-d2bd-481436f535eb@rasmusvillemoes.dk>
On Thu, Feb 18, 2021 at 11:51:43PM +0100, Rasmus Villemoes wrote:
> On 18/02/2021 05.05, Yury Norov wrote:
> > BITMAP_{LAST,FIRST}_WORD_MASK() in linux/bitmap.h duplicates the
> > functionality of GENMASK(). The scope of there macros is wider
> > than just bitmap. This patch defines 4 new macros: BITS_FIRST(),
> > BITS_LAST(), BITS_FIRST_MASK() and BITS_LAST_MASK() in linux/bits.h
> > on top of GENMASK() and replaces BITMAP_{LAST,FIRST}_WORD_MASK()
> > to avoid duplication and increase the scope of the macros.
> >
>
> Please include some info on changes in generated code, if any. When the
> parameter to the macro is a constant I'm sure it all folds to a
> compile-time constant either way, but when it's not, I'm not sure gcc
> can do the same optimizations when the expressions become more complicated.
After applying all patches till "tools: introduce SMALL_CONST() macro",
there's no visible changes in code generation:
scripts/bloat-o-meter vmlinux.before vmlinux
add/remove: 1/2 grow/shrink: 2/0 up/down: 17/-16 (1)
Function old new delta
ethtool_get_drvinfo 900 908 +8
e843419@0cf2_0001309d_7f0 - 8 +8
vermagic 48 49 +1
e843419@0d45_000138bb_f68 8 - -8
e843419@0cc9_00012bce_198c 8 - -8
Total: Before=26092016, After=26092017, chg +0.00%
The build is arm64, and the compilerr is:
aarch64-linux-gnu-gcc (Linaro GCC 7.3-2018.05) 7.3.1 20180425
next prev parent reply other threads:[~2021-03-12 4:31 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-18 4:04 [PATCH v3 00/14] lib/find_bit: fast path for small bitmaps Yury Norov
2021-02-18 4:04 ` [PATCH 01/14] tools: disable -Wno-type-limits Yury Norov
2021-02-18 4:05 ` [PATCH 02/14] tools: bitmap: sync function declarations with the kernel Yury Norov
2021-02-18 4:05 ` [PATCH 03/14] arch: rearrange headers inclusion order in asm/bitops for m68k and sh Yury Norov
2021-02-18 4:05 ` [PATCH 04/14] lib: introduce BITS_{FIRST,LAST} macro Yury Norov
2021-02-18 22:51 ` Rasmus Villemoes
2021-03-12 4:30 ` Yury Norov [this message]
2021-02-18 4:05 ` [PATCH 05/14] tools: sync BITS_MASK macros with the kernel Yury Norov
2021-02-18 4:05 ` [PATCH 06/14] bitsperlong.h: introduce SMALL_CONST() macro Yury Norov
2021-02-18 23:07 ` Rasmus Villemoes
2021-03-12 5:28 ` Yury Norov
2021-03-12 9:12 ` Rasmus Villemoes
2021-03-12 21:53 ` Yury Norov
2021-02-18 4:05 ` [PATCH 07/14] tools: " Yury Norov
2021-02-18 4:05 ` [PATCH 08/14] lib/Kconfig: introduce FAST_PATH option Yury Norov
2021-02-18 15:15 ` Andy Shevchenko
2021-02-18 19:24 ` Yury Norov
2021-02-19 10:52 ` Andy Shevchenko
2021-02-18 4:05 ` [PATCH 09/14] lib: inline _find_next_bit() wrappers Yury Norov
2021-02-18 4:05 ` [PATCH 10/14] tools: sync find_next_bit implementation Yury Norov
2021-02-18 4:05 ` [PATCH 11/14] lib: add fast path for find_next_*_bit() Yury Norov
2021-02-18 15:24 ` Andy Shevchenko
2021-02-18 4:05 ` [PATCH 12/14] lib: add fast path for find_first_*_bit() and find_last_bit() Yury Norov
2021-02-18 4:05 ` [PATCH 13/14] tools: sync lib/find_bit implementation Yury Norov
2021-02-18 4:05 ` [PATCH 14/14] MAINTAINERS: Add entry for the bitmap API Yury Norov
2021-02-18 15:28 ` Andy Shevchenko
2021-02-18 15:34 ` Yury Norov
2021-03-12 9:15 ` Rasmus Villemoes
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