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Date: Fri, 8 Jan 2016 15:02:47 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ingo Molnar <mingo@...nel.org>
Cc: linux-kernel@...r.kernel.org,
Arnaldo Carvalho de Melo <acme@...hat.com>,
Adrian Hunter <adrian.hunter@...el.com>,
Borislav Petkov <bp@...e.de>, David Ahern <dsahern@...il.com>,
George@...radead.org, "Spelvin <linux"@horizon.com,
Jiri Olsa <jolsa@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
Rasmus Villemoes <linux@...musvillemoes.dk>,
Wang Nan <wangnan0@...wei.com>,
Yury Norov <yury.norov@...il.com>
Subject: [PATCH 40/59] tools lib: Sync tools/lib/find_bit.c with the kernel
From: Arnaldo Carvalho de Melo <acme@...hat.com>
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@...el.com>
Cc: Borislav Petkov <bp@...e.de>
Cc: David Ahern <dsahern@...il.com>
Cc: George Spelvin <linux@...izon.com
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Rasmus Villemoes <linux@...musvillemoes.dk>
Cc: Wang Nan <wangnan0@...wei.com>
Cc: Yury Norov <yury.norov@...il.com>
Link: http://lkml.kernel.org/n/tip-5fys65wkd7gu8j7a7xgukc5t@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
tools/lib/find_bit.c | 103 ++++++++++++++++-----------------
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@...hat.com)
*
+ * Copyright (C) 2008 IBM Corporation
+ * 'find_last_bit' is written by Rusty Russell <rusty@...tcorp.com.au>
+ * (Inspired by David Howell's find_next_bit implementation)
+ *
+ * Rewritten by Yury Norov <yury.norov@...il.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) ? \
--
2.1.0
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