From: Yury Norov <yury.norov@gmail.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Lucas Stach <l.stach@pengutronix.de>,
Russell King <linux+etnaviv@armlinux.org.uk>,
Christian Gmeiner <christian.gmeiner@gmail.com>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Jean Delvare <jdelvare@suse.com>,
Guenter Roeck <linux@roeck-us.net>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>,
Marc Zyngier <maz@kernel.org>,
David Woodhouse <dwmw@amazon.co.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Wei Yang <richard.weiyang@linux.alibaba.com>,
Geert Uytterhoeven <geert+renesas@glider.be>,
Alexey Klimov <aklimov@redhat.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
etnaviv@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
linux-hwmon@vger.kernel.org
Cc: Yury Norov <yury.norov@gmail.com>
Subject: [PATCH 2/3] find: micro-optimize for_each_{set,clear}_bit()
Date: Fri, 18 Jun 2021 12:57:34 -0700 [thread overview]
Message-ID: <20210618195735.55933-3-yury.norov@gmail.com> (raw)
In-Reply-To: <20210618195735.55933-1-yury.norov@gmail.com>
The macros iterate thru all set/clear bits in a bitmap. They search a
first bit using find_first_bit(), and the rest bits using find_next_bit().
Since find_next_bit() is called shortly after find_first_bit(), we can
save few lines of I-cache by not using find_first_bit().
Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
include/linux/find.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/find.h b/include/linux/find.h
index 4500e8ab93e2..ae9ed52b52b8 100644
--- a/include/linux/find.h
+++ b/include/linux/find.h
@@ -280,7 +280,7 @@ unsigned long find_next_bit_le(const void *addr, unsigned
#endif
#define for_each_set_bit(bit, addr, size) \
- for ((bit) = find_first_bit((addr), (size)); \
+ for ((bit) = find_next_bit((addr), (size), 0); \
(bit) < (size); \
(bit) = find_next_bit((addr), (size), (bit) + 1))
@@ -291,7 +291,7 @@ unsigned long find_next_bit_le(const void *addr, unsigned
(bit) = find_next_bit((addr), (size), (bit) + 1))
#define for_each_clear_bit(bit, addr, size) \
- for ((bit) = find_first_zero_bit((addr), (size)); \
+ for ((bit) = find_next_zero_bit((addr), (size), 0); \
(bit) < (size); \
(bit) = find_next_zero_bit((addr), (size), (bit) + 1))
--
2.30.2
next prev parent reply other threads:[~2021-06-19 7:44 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-18 19:57 [PATCH 0/3] for_each_*_bit: move to find.h and reconsider Yury Norov
2021-06-18 19:57 ` [PATCH 1/3] include/linux: move for_each_bit() macros from bitops.h to find.h Yury Norov
2021-06-19 10:50 ` Andy Shevchenko
2021-06-18 19:57 ` Yury Norov [this message]
2021-06-19 10:50 ` [PATCH 2/3] find: micro-optimize for_each_{set,clear}_bit() Andy Shevchenko
2021-06-19 16:24 ` Marc Zyngier
2021-06-19 17:28 ` Yury Norov
2021-06-27 16:47 ` Yury Norov
2021-06-18 19:57 ` [PATCH 3/3] Replace for_each_*_bit_from() with for_each_*_bit() where appropriate Yury Norov
2021-06-19 10:49 ` Andy Shevchenko
2021-06-19 10:55 ` Andy Shevchenko
2021-06-21 20:17 ` Guenter Roeck
2021-06-21 21:34 ` Yury Norov
2021-07-28 14:57 ` [PATCH 0/3] for_each_*_bit: move to find.h and reconsider Yury Norov
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