kernel/linux.git/lib/bsearch.c, branch v6.6.132

lib/bsearch: Provide __always_inline variant

2020-06-11T13:14:53+00:00

For code that needs the ultimate performance (it can inline the @cmp function too) or simply needs to avoid calling external functions for whatever reason, provide an __always_inline variant of bsearch(). [ tglx: Renamed to __inline_bsearch() as suggested by Andy ] Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Thomas Gleixner Reviewed-by: Alexandre Chartre Acked-by: Andy Lutomirski Link: https://lkml.kernel.org/r/20200505135313.624443814@linutronix.de

lib/bsearch: Use generic type for comparator function

2019-11-14T18:15:11+00:00

Comparator function type, cmp_func_t, is defined in the types.h, use it in bsearch() and, thus, add more sense to the corresponding comment in the code. Link: http://lkml.kernel.org/r/20191007135656.37734-2-andriy.shevchenko@linux.intel.com Signed-off-by: Andy Shevchenko Signed-off-by: Steven Rostedt (VMware)

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 372

2019-06-05T15:37:10+00:00

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation version 2 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 135 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190531081036.435762997@linutronix.de Signed-off-by: Greg Kroah-Hartman

kprobes: Prohibit probing on bsearch()

2019-02-13T07:16:41+00:00

Since kprobe breakpoing handler is using bsearch(), probing on this routine can cause recursive breakpoint problem. int3 ->do_int3() ->ftrace_int3_handler() ->ftrace_location() ->ftrace_location_range() ->bsearch() -> int3 Prohibit probing on bsearch(). Signed-off-by: Andrea Righi Acked-by: Masami Hiramatsu Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mathieu Desnoyers Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/154998813406.31052.8791425358974650922.stgit@devbox Signed-off-by: Ingo Molnar

lib/bsearch.c: micro-optimize pivot position calculation

2017-07-10T23:32:35+00:00

There is a slightly faster way (in terms of the number of instructions being used) to calculate the position of a middle element, preserving integer overflow safeness. ./scripts/bloat-o-meter lib/bsearch.o.old lib/bsearch.o.new add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-24 (-24) function old new delta bsearch 122 98 -24 TEST INT array of size 100001, elements [0..100000]. gcc 7.1, Os, x86_64. a) bsearch() of existing key "100001 - 2": BASE ==== $ perf stat ./a.out Performance counter stats for './a.out': 619.445196 task-clock:u (msec) # 0.999 CPUs utilized 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 133 page-faults:u # 0.215 K/sec 1,949,517,279 cycles:u # 3.147 GHz (83.06%) 181,017,938 stalled-cycles-frontend:u # 9.29% frontend cycles idle (83.05%) 82,959,265 stalled-cycles-backend:u # 4.26% backend cycles idle (67.02%) 4,355,706,383 instructions:u # 2.23 insn per cycle # 0.04 stalled cycles per insn (83.54%) 1,051,539,242 branches:u # 1697.550 M/sec (83.54%) 15,263,381 branch-misses:u # 1.45% of all branches (83.43%) 0.620082548 seconds time elapsed PATCHED ======= $ perf stat ./a.out Performance counter stats for './a.out': 475.097316 task-clock:u (msec) # 0.999 CPUs utilized 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 135 page-faults:u # 0.284 K/sec 1,487,467,717 cycles:u # 3.131 GHz (82.95%) 186,537,162 stalled-cycles-frontend:u # 12.54% frontend cycles idle (82.93%) 28,797,869 stalled-cycles-backend:u # 1.94% backend cycles idle (67.10%) 3,807,564,203 instructions:u # 2.56 insn per cycle # 0.05 stalled cycles per insn (83.57%) 1,049,344,291 branches:u # 2208.693 M/sec (83.60%) 5,485 branch-misses:u # 0.00% of all branches (83.58%) 0.475760235 seconds time elapsed b) bsearch() of un-existing key "100001 + 2": BASE ==== $ perf stat ./a.out Performance counter stats for './a.out': 499.244480 task-clock:u (msec) # 0.999 CPUs utilized 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 132 page-faults:u # 0.264 K/sec 1,571,194,855 cycles:u # 3.147 GHz (83.18%) 13,450,980 stalled-cycles-frontend:u # 0.86% frontend cycles idle (83.18%) 21,256,072 stalled-cycles-backend:u # 1.35% backend cycles idle (66.78%) 4,171,197,909 instructions:u # 2.65 insn per cycle # 0.01 stalled cycles per insn (83.68%) 1,009,175,281 branches:u # 2021.405 M/sec (83.79%) 3,122 branch-misses:u # 0.00% of all branches (83.37%) 0.499871144 seconds time elapsed PATCHED ======= $ perf stat ./a.out Performance counter stats for './a.out': 399.023499 task-clock:u (msec) # 0.998 CPUs utilized 0 context-switches:u # 0.000 K/sec 0 cpu-migrations:u # 0.000 K/sec 134 page-faults:u # 0.336 K/sec 1,245,793,991 cycles:u # 3.122 GHz (83.39%) 11,529,273 stalled-cycles-frontend:u # 0.93% frontend cycles idle (83.46%) 12,116,311 stalled-cycles-backend:u # 0.97% backend cycles idle (66.92%) 3,679,710,005 instructions:u # 2.95 insn per cycle # 0.00 stalled cycles per insn (83.47%) 1,009,792,625 branches:u # 2530.660 M/sec (83.46%) 2,590 branch-misses:u # 0.00% of all branches (83.12%) 0.399733539 seconds time elapsed Link: http://lkml.kernel.org/r/20170607150457.5905-1-sergey.senozhatsky@gmail.com Signed-off-by: Sergey Senozhatsky Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

lib: reduce the use of module.h wherever possible

2012-03-07T20:04:04+00:00

For files only using THIS_MODULE and/or EXPORT_SYMBOL, map them onto including export.h -- or if the file isn't even using those, then just delete the include. Fix up any implicit include dependencies that were being masked by module.h along the way. Signed-off-by: Paul Gortmaker

lib: Add generic binary search function to the kernel.

2011-05-19T07:25:27+00:00

There a large number hand-coded binary searches in the kernel (run "git grep search | grep binary" to find many of them). Since in my experience, hand-coding binary searches can be error-prone, it seems worth cleaning this up by providing a generic binary search function. This generic binary search implementation comes from Ksplice. It has the same basic API as the C library bsearch() function. Ksplice uses it in half a dozen places with 4 different comparison functions, and I think our code is substantially cleaner because of this. Signed-off-by: Tim Abbott Extra-bikeshedding-by: Alan Jenkins Extra-bikeshedding-by: André Goddard Rosa Extra-bikeshedding-by: Rusty Russell Signed-off-by: Rusty Russell Signed-off-by: Alessio Igor Bogani Signed-off-by: Rusty Russell