diff options
author | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-01-08 11:26:43 -0300 |
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committer | Arnaldo Carvalho de Melo <acme@redhat.com> | 2016-01-08 12:35:41 -0300 |
commit | 64af4e0da419ef9e9db0d34a3b5836adbf90a5e8 (patch) | |
tree | e22b8af5c7a2bd592c64b6b4fb6dc8094aa73be1 /tools | |
parent | 552eb975b83756e3d95aeb5edaeb5c3c032b0021 (diff) | |
download | linux-64af4e0da419ef9e9db0d34a3b5836adbf90a5e8.tar.bz2 |
tools lib: Sync tools/lib/find_bit.c with the kernel
Need to move the bitmap.[ch] things from tools/perf/ to tools/lib, will
be done in the next patches.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: George Spelvin <linux@horizon.com
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Yury Norov <yury.norov@gmail.com>
Link: http://lkml.kernel.org/n/tip-5fys65wkd7gu8j7a7xgukc5t@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r-- | tools/lib/find_bit.c | 103 | ||||
-rw-r--r-- | tools/perf/util/include/linux/bitmap.h | 2 |
2 files changed, 51 insertions, 54 deletions
diff --git a/tools/lib/find_bit.c b/tools/lib/find_bit.c index 732d8c38d2c3..9122a9e80046 100644 --- a/tools/lib/find_bit.c +++ b/tools/lib/find_bit.c @@ -1,10 +1,17 @@ -/* find_next_bit.c: fallback find next bit implementation +/* bit search implementation * - * Copied from lib/find_next_bit.c to tools/lib/find_bit.c + * Copied from lib/find_bit.c to tools/lib/find_bit.c * * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * + * Copyright (C) 2008 IBM Corporation + * 'find_last_bit' is written by Rusty Russell <rusty@rustcorp.com.au> + * (Inspired by David Howell's find_next_bit implementation) + * + * Rewritten by Yury Norov <yury.norov@gmail.com> to decrease + * size and improve performance, 2015. + * * 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; either version @@ -12,52 +19,50 @@ */ #include <linux/bitops.h> -#include <asm/types.h> -#include <asm/byteorder.h> +#include <linux/bitmap.h> +#include <linux/kernel.h> -#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG) +#if !defined(find_next_bit) -#ifndef find_next_bit /* - * Find the next set bit in a memory region. + * This is a common helper function for find_next_bit and + * find_next_zero_bit. The difference is the "invert" argument, which + * is XORed with each fetched word before searching it for one bits. */ -unsigned long find_next_bit(const unsigned long *addr, unsigned long size, - unsigned long offset) +static unsigned long _find_next_bit(const unsigned long *addr, + unsigned long nbits, unsigned long start, unsigned long invert) { - const unsigned long *p = addr + BITOP_WORD(offset); - unsigned long result = offset & ~(BITS_PER_LONG-1); unsigned long tmp; - if (offset >= size) - return size; - size -= result; - offset %= BITS_PER_LONG; - if (offset) { - tmp = *(p++); - tmp &= (~0UL << offset); - if (size < BITS_PER_LONG) - goto found_first; - if (tmp) - goto found_middle; - size -= BITS_PER_LONG; - result += BITS_PER_LONG; - } - while (size & ~(BITS_PER_LONG-1)) { - if ((tmp = *(p++))) - goto found_middle; - result += BITS_PER_LONG; - size -= BITS_PER_LONG; + if (!nbits || start >= nbits) + return nbits; + + tmp = addr[start / BITS_PER_LONG] ^ invert; + + /* Handle 1st word. */ + tmp &= BITMAP_FIRST_WORD_MASK(start); + start = round_down(start, BITS_PER_LONG); + + while (!tmp) { + start += BITS_PER_LONG; + if (start >= nbits) + return nbits; + + tmp = addr[start / BITS_PER_LONG] ^ invert; } - if (!size) - return result; - tmp = *p; -found_first: - tmp &= (~0UL >> (BITS_PER_LONG - size)); - if (tmp == 0UL) /* Are any bits set? */ - return result + size; /* Nope. */ -found_middle: - return result + __ffs(tmp); + return min(start + __ffs(tmp), nbits); +} +#endif + +#ifndef find_next_bit +/* + * Find the next set bit in a memory region. + */ +unsigned long find_next_bit(const unsigned long *addr, unsigned long size, + unsigned long offset) +{ + return _find_next_bit(addr, size, offset, 0UL); } #endif @@ -67,23 +72,13 @@ found_middle: */ unsigned long find_first_bit(const unsigned long *addr, unsigned long size) { - const unsigned long *p = addr; - unsigned long result = 0; - unsigned long tmp; + unsigned long idx; - while (size & ~(BITS_PER_LONG-1)) { - if ((tmp = *(p++))) - goto found; - result += BITS_PER_LONG; - size -= BITS_PER_LONG; + for (idx = 0; idx * BITS_PER_LONG < size; idx++) { + if (addr[idx]) + return min(idx * BITS_PER_LONG + __ffs(addr[idx]), size); } - if (!size) - return result; - tmp = (*p) & (~0UL >> (BITS_PER_LONG - size)); - if (tmp == 0UL) /* Are any bits set? */ - return result + size; /* Nope. */ -found: - return result + __ffs(tmp); + return size; } #endif diff --git a/tools/perf/util/include/linux/bitmap.h b/tools/perf/util/include/linux/bitmap.h index 40bd21488032..28f5493da491 100644 --- a/tools/perf/util/include/linux/bitmap.h +++ b/tools/perf/util/include/linux/bitmap.h @@ -11,6 +11,8 @@ int __bitmap_weight(const unsigned long *bitmap, int bits); void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1, const unsigned long *bitmap2, int bits); +#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1))) + #define BITMAP_LAST_WORD_MASK(nbits) \ ( \ ((nbits) % BITS_PER_LONG) ? \ |