kernel/linux.git/include/linux/find.h, branch v6.12.80

find: Switch from inline to __always_inline

2024-08-18T17:07:59+00:00

'inline' keyword is only a recommendation for compiler. If it decides to not inline find_bit nodemask functions, the whole small_const_nbits() machinery doesn't work. This is how a standard GCC 11.3.0 does for my x86_64 build now. This patch replaces 'inline' directive with unconditional '__always_inline' to make sure that there's always a chance for compile-time optimization. It doesn't change size of kernel image, according to bloat-o-meter. [[ Brian: split out from: Subject: [PATCH 1/3] bitmap: switch from inline to __always_inline https://lore.kernel.org/all/20221027043810.350460-2-yury.norov@gmail.com/ But rewritten, as there were too many conflicts. ]] Co-developed-by: Brian Norris Signed-off-by: Brian Norris Reviewed-by: Kees Cook Reviewed-by: Nathan Chancellor Signed-off-by: Yury Norov

Merge tag 'bitmap-for-6.10v2' of https://github.com/norov/linux

2024-05-21T22:29:01+00:00

Pull bitmap updates from Yury Norov: - topology_span_sane() optimization from Kyle Meyer - fns() rework from Kuan-Wei Chiu (used in cpumask_local_spread() and other places) - headers cleanup from Andy - add a MAINTAINERS record for bitops API * tag 'bitmap-for-6.10v2' of https://github.com/norov/linux: usercopy: Don't use "proxy" headers bitops: Move aligned_byte_mask() to wordpart.h MAINTAINERS: add BITOPS API record bitmap: relax find_nth_bit() limitation on return value lib: make test_bitops compilable into the kernel image bitops: Optimize fns() for improved performance lib/test_bitops: Add benchmark test for fns() Compiler Attributes: Add __always_used macro sched/topology: Optimize topology_span_sane() cpumask: Add for_each_cpu_from()

bitmap: relax find_nth_bit() limitation on return value

2024-05-09T16:25:08+00:00

The function claims to return the bitmap size, if Nth bit doesn't exist. This rule is violated in inline case because the fns() that is used there doesn't know anything about size of the bitmap. So, relax this requirement to '>= size', and make the outline implementation a bit cheaper. All in-tree kernel users of find_nth_bit() are safe against that. Reported-by: Rasmus Villemoes Closes: https://lore.kernel.org/all/Zi50cAgR8nZvgLa3@yury-ThinkPad/T/#m6da806a0525e74dcc91f35e5f20766ed4e853e8a Signed-off-by: Yury Norov

cpumask: Introduce cpumask_first_and_and()

2024-04-24T19:23:49+00:00

Introduce cpumask_first_and_and() to get intersection between 3 cpumasks, free of any intermediate cpumask variable. Instead, cpumask_first_and_and() works in-place with all inputs and produces desired output directly. Signed-off-by: Dawei Li Signed-off-by: Thomas Gleixner Acked-by: Yury Norov Link: https://lore.kernel.org/r/20240416085454.3547175-2-dawei.li@shingroup.cn

lib/find: optimize find_*_bit_wrap

2023-12-03T18:28:17+00:00

When an offset is 0, there's no need to search a bitmap from the beginning after the 1st search failed, because each bit has already been tested. Signed-off-by: Yury Norov

lib/find_bit: Fix the code comments about find_next_bit_wrap

2023-12-03T18:28:16+00:00

The function find_next_bit_wrap only has one memory region to search on. Adjust the comments. Signed-off-by: Guanjun Signed-off-by: Yury Norov

cpumask: introduce for_each_cpu_or

2023-03-19T17:02:04+00:00

Equivalent of for_each_cpu_and, except it ORs the two masks together so it iterates all the CPUs present in either mask. Signed-off-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

lib/find: introduce find_nth_and_andnot_bit

2023-02-08T02:20:00+00:00

In the following patches the function is used to implement in-place bitmaps traversing without storing intermediate result in temporary bitmaps. Signed-off-by: Yury Norov Acked-by: Tariq Toukan Reviewed-by: Jacob Keller Reviewed-by: Peter Lafreniere Signed-off-by: Jakub Kicinski

cpumask: Introduce for_each_cpu_andnot()

2022-10-06T12:57:36+00:00

for_each_cpu_and() is very convenient as it saves having to allocate a temporary cpumask to store the result of cpumask_and(). The same issue applies to cpumask_andnot() which doesn't actually need temporary storage for iteration purposes. Following what has been done for for_each_cpu_and(), introduce for_each_cpu_andnot(). Signed-off-by: Valentin Schneider

lib/find_bit: Introduce find_next_andnot_bit()

2022-10-06T12:57:36+00:00

In preparation of introducing for_each_cpu_andnot(), add a variant of find_next_bit() that negate the bits in @addr2 when ANDing them with the bits in @addr1. Signed-off-by: Valentin Schneider