From: Yury Norov <yury.norov@gmail.com>
To: linux-kernel@vger.kernel.org,
"Alexander Lobakin" <alexandr.lobakin@intel.com>,
"Andy Shevchenko" <andriy.shevchenko@linux.intel.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"David Gow" <davidgow@google.com>,
"Eric Dumazet" <edumazet@google.com>,
"Isabella Basso" <isabbasso@riseup.net>,
"Kees Cook" <keescook@chromium.org>,
"Keith Busch" <kbusch@kernel.org>,
"Kumar Kartikeya Dwivedi" <memxor@gmail.com>,
"Marco Elver" <elver@google.com>,
"Mark Rutland" <mark.rutland@arm.com>,
"Rasmus Villemoes" <linux@rasmusvillemoes.dk>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Toke Høiland-Jørgensen" <toke@redhat.com>
Cc: Yury Norov <yury.norov@gmail.com>
Subject: [PATCH v2 0/5] lib/find: add find_nth_bit()
Date: Sun, 10 Jul 2022 21:47:06 -0700 [thread overview]
Message-ID: <20220711044711.466822-1-yury.norov@gmail.com> (raw)
Kernel lacks for a function that searches for Nth bit in a bitmap.
Usually people do it like this:
for_each_set_bit(bit, mask, size)
if (--n == 0)
return bit;
Which is not so elegant, and very slow.
This series adds fast routines for this task, and applies them where
appropriate.
While here, move thin wrappers around find_bit() in nodemask.c to a
corresponding header, and because nodemask.c is empty after that,
remove it.
v1: https://lore.kernel.org/lkml/20220706182300.70862-4-yury.norov@gmail.com/T/
v2: - count Nth bit from 0 (was 1);
- use 'invert' trick in _find_nth_bit(), as in _find_next_bit();
- cleanup comments;
- fns() is kept inline - looking at __ffs() generic implementation,
I decided to keep it untouched.
Yury Norov (5):
lib: add find_nth(,and,andnot)_bit()
lib/bitmap: add tests for find_nth_bit()
lib/bitmap: remove bitmap_ord_to_pos
cpumask: add cpumask_nth_{,and,andnot}
lib/nodemask: inline next_node_in() and node_random()
MAINTAINERS | 1 -
include/linux/bitmap.h | 1 -
include/linux/bitops.h | 19 +++++++++
include/linux/cpumask.h | 44 +++++++++++++++++++++
include/linux/find.h | 83 ++++++++++++++++++++++++++++++++++++++++
include/linux/nodemask.h | 27 ++++++++++---
lib/Makefile | 2 +-
lib/bitmap.c | 36 ++---------------
lib/cpumask.c | 26 ++++++-------
lib/find_bit.c | 20 ++++++++++
lib/find_bit_benchmark.c | 17 ++++++++
lib/nodemask.c | 31 ---------------
lib/test_bitmap.c | 36 ++++++++++++++++-
13 files changed, 254 insertions(+), 89 deletions(-)
delete mode 100644 lib/nodemask.c
--
2.34.1
next reply other threads:[~2022-07-11 4:47 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-11 4:47 Yury Norov [this message]
2022-07-11 4:47 ` [PATCH 1/5] lib: add find_nth(,and,andnot)_bit() Yury Norov
2022-07-11 4:47 ` [PATCH 2/5] lib/bitmap: add tests for find_nth_bit() Yury Norov
2022-07-11 4:47 ` [PATCH 3/5] lib/bitmap: remove bitmap_ord_to_pos Yury Norov
2022-07-11 4:47 ` [PATCH 4/5] cpumask: add cpumask_nth_{,and,andnot} Yury Norov
2022-07-11 4:47 ` [PATCH 5/5] lib/nodemask: inline next_node_in() and node_random() Yury Norov
2022-07-29 3:46 ` Guenter Roeck
2022-07-29 16:48 ` Yury Norov
2022-08-13 13:15 ` Guenter Roeck
2022-08-13 13:48 ` Yury Norov
2022-08-14 18:48 ` Andy Shevchenko
2022-08-14 18:51 ` Andy Shevchenko
2022-07-11 8:55 ` [PATCH v2 0/5] lib/find: add find_nth_bit() Andy Shevchenko
2022-07-12 16:26 ` Yury Norov
2022-07-12 18:28 ` Andy Shevchenko
2022-07-13 1:46 ` Yury Norov
2022-07-15 1:04 ` Yury Norov
2022-07-21 21:14 ` Yury Norov
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