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[PATCH 40/59] tools lib: Sync tools/lib/find_bit.c with the kernel

From Arnaldo Carvalho de Melo <acme@kernel.org>
Newsgroups linux.kernel
Subject [PATCH 40/59] tools lib: Sync tools/lib/find_bit.c with the kernel
Date 2016-01-08 19:10 +0100
Message-ID <qOJE5-21e-7@gated-at.bofh.it> (permalink)
References <qOJE5-21e-1@gated-at.bofh.it>
Organization linux.* mail to news gateway

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From: Arnaldo Carvalho de Melo <acme@redhat.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@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>
---
 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@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) ?					\
-- 
2.1.0

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[GIT PULL 00/59] perf/core improvements and fixes Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 24/59] perf script: Process stat config event Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 40/59] tools lib: Sync tools/lib/find_bit.c with the kernel Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 49/59] perf tools: Add overhead/overhead_children keys defaults via string Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 39/59] tools lib: Move find_next_bit.c to tools/lib/ Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 42/59] perf top: Decay periods in callchains Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 15/59] tools build feature: Fix feature_check_display_code typo Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 23/59] perf script: Process cpu/threads maps Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 43/59] perf report: Change default to use event group view Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 05/59] perf tools: Pass evlist to setup_sorting() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 10/59] perf tools: Support shortcuts for events in dynamic sort keys Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 13/59] perf tools: Add 'trace_fields' dynamic sort key Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 59/59] perf evlist: Add --trace-fields option to show trace fields Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 52/59] perf report: Show random usage tip on the help line Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 48/59] perf tools: Remove list entry from struct sort_entry Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 14/59] perf tools: Make 'trace' or 'trace_fields' sort key default for tracepoint events Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 25/59] perf script: Add process_stat/process_stat_interval scripting interface Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 41/59] tools lib: Move bitmap.[ch] from tools/perf/ to tools/{lib,include}/ Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 02/59] perf hist: Save raw_data/size for tracepoint events Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 08/59] perf tools: Add 'trace' sort key Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 09/59] perf report/top: Add --raw-trace option Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 45/59] perf tools: Add missing headers in perf's MANIFEST Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:10 +0100
  [PATCH 57/59] perf libdw: Check for mmaps also in MAP__VARIABLE tree Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 56/59] perf unwind: Check for mmaps also in MAP__VARIABLE tree Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 53/59] perf evlist: Make perf_evlist__open() open evsels with their cpus and threads (like perf record does) Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 58/59] perf record: Store data mmaps for dwarf unwind Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 47/59] perf tools: Include all tools/lib directory for tags/cscope/TAGS targets Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 54/59] perf evlist: Remove perf_evlist__(enable|disable)_event functions Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 51/59] perf hists: Export a couple of hist functions Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 12/59] perf tools: Skip dynamic fields not defined for current event Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 03/59] tools lib traceevent: Factor out and export print_event_field[s]() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 38/59] perf tests: Give a bit more information on the CQM test failure path Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 37/59] perf tests: No need to set attr.sample_freq for tracking !PERF_RECORD_SAMPLE Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 11/59] perf tools: Support '<event>.*' dynamic sort key Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 04/59] perf top: Create the evlist sooner Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 46/59] perf script: Align event name properly Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 50/59] perf diff: Use perf_hpp__register_sort_field interface Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 18/59] tools build feature: Use value assignment form for FEATURE-DUMP file Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 35/59] perf test: No need for setting attr.sample_freq on the RECORD test Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 33/59] perf evlist: Introduce perf_evlist__new_dummy constructor Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 36/59] perf python: Add missing files to binding link list Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 55/59] perf unwind: Use find_map function in access_dso_mem Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:20 +0100
  [PATCH 19/59] perf build: Use FEATURE-DUMP in bpf subproject Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 28/59] perf cpumap: Fix cpu conversion in cpu_map__from_entries Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 29/59] perf script: Display stat events by default Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 07/59] perf tools: Try to show pretty printed output for dynamic sort keys Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 16/59] tools build feature: Move dwarf post unwind choice output into perf Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 20/59] perf tools: Add all matching dynamic sort keys for field name Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 26/59] perf script: Add stat default handlers Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 44/59] perf tools: Do not show trace command if it's not compiled in Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 27/59] perf script: Add python support for stat events Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 21/59] perf report: Add documentation for dynamic sort keys Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 30/59] perf script: Add stat-cpi.py script Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 34/59] perf test: Use "dummy" events in the PERF_RECORD_ test Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 17/59] tools build feature: Introduce feature_assign macro Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 31/59] perf pmu: fix alias->snapshot missing initialization bug Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 32/59] perf tests: No need to set attr.sample_freq in the perf time to TSC test Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 01/59] perf hist: Pass struct sample to __hists__add_entry() Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 06/59] perf tools: Add dynamic sort key for tracepoint events Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  [PATCH 22/59] perf stat record: Keep sample_type 0 for pipe session Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-01-08 19:30 +0100
  Re: [GIT PULL 00/59] perf/core improvements and fixes Ingo Molnar <mingo@kernel.org> - 2016-01-09 17:30 +0100

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