From: Alexander van Heukelum <heukelum@mailshack.com>
Date: Sun, 9 Mar 2008 20:01:04 +0000 (+0100)
Subject: x86: change x86 to use generic find_next_bit
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=6fd92b63d0626a8fe7eb8e2e50d19ecaa18cb412;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git
x86: change x86 to use generic find_next_bit
The versions with inline assembly are in fact slower on the machines I
tested them on (in userspace) (Athlon XP 2800+, p4-like Xeon 2.8GHz, AMD
Opteron 270). The i386-version needed a fix similar to 06024f21 to avoid
crashing the benchmark.
Benchmark using: gcc -fomit-frame-pointer -Os. For each bitmap size
1...512, for each possible bitmap with one bit set, for each possible
offset: find the position of the first bit starting at offset. If you
follow ;). Times include setup of the bitmap and checking of the
results.
Athlon Xeon Opteron 32/64bit
x86-specific: 0m3.692s 0m2.820s 0m3.196s / 0m2.480s
generic: 0m2.622s 0m1.662s 0m2.100s / 0m1.572s
If the bitmap size is not a multiple of BITS_PER_LONG, and no set
(cleared) bit is found, find_next_bit (find_next_zero_bit) returns a
value outside of the range [0, size]. The generic version always returns
exactly size. The generic version also uses unsigned long everywhere,
while the x86 versions use a mishmash of int, unsigned (int), long and
unsigned long.
Using the generic version does give a slightly bigger kernel, though.
defconfig: text data bss dec hex filename
x86-specific: 4738555 481232 626688 5846475 5935cb vmlinux (32 bit)
generic: 4738621 481232 626688 5846541 59360d vmlinux (32 bit)
x86-specific: 5392395 846568 724424 6963387 6a40bb vmlinux (64 bit)
generic: 5392458 846568 724424 6963450 6a40fa vmlinux (64 bit)
Signed-off-by: Alexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 2fadf794483d..5639de47ed45 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -77,6 +77,9 @@ config GENERIC_BUG
def_bool y
depends on BUG
+config GENERIC_FIND_NEXT_BIT
+ def_bool y
+
config GENERIC_HWEIGHT
def_bool y
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 25df1c1989fe..436093299bd3 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -11,7 +11,7 @@ lib-y += memcpy_$(BITS).o
ifeq ($(CONFIG_X86_32),y)
lib-y += checksum_32.o
lib-y += strstr_32.o
- lib-y += bitops_32.o semaphore_32.o string_32.o
+ lib-y += semaphore_32.o string_32.o
lib-$(CONFIG_X86_USE_3DNOW) += mmx_32.o
else
diff --git a/arch/x86/lib/bitops_32.c b/arch/x86/lib/bitops_32.c
deleted file mode 100644
index b65440459859..000000000000
--- a/arch/x86/lib/bitops_32.c
+++ /dev/null
@@ -1,70 +0,0 @@
-#include <linux/bitops.h>
-#include <linux/module.h>
-
-/**
- * find_next_bit - find the next set bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bitnumber to start searching at
- * @size: The maximum size to search
- */
-int find_next_bit(const unsigned long *addr, int size, int offset)
-{
- const unsigned long *p = addr + (offset >> 5);
- int set = 0, bit = offset & 31, res;
-
- if (bit) {
- /*
- * Look for nonzero in the first 32 bits:
- */
- __asm__("bsfl %1,%0\n\t"
- "jne 1f\n\t"
- "movl $32, %0\n"
- "1:"
- : "=r" (set)
- : "r" (*p >> bit));
- if (set < (32 - bit))
- return set + offset;
- set = 32 - bit;
- p++;
- }
- /*
- * No set bit yet, search remaining full words for a bit
- */
- res = find_first_bit (p, size - 32 * (p - addr));
- return (offset + set + res);
-}
-EXPORT_SYMBOL(find_next_bit);
-
-/**
- * find_next_zero_bit - find the first zero bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bitnumber to start searching at
- * @size: The maximum size to search
- */
-int find_next_zero_bit(const unsigned long *addr, int size, int offset)
-{
- const unsigned long *p = addr + (offset >> 5);
- int set = 0, bit = offset & 31, res;
-
- if (bit) {
- /*
- * Look for zero in the first 32 bits.
- */
- __asm__("bsfl %1,%0\n\t"
- "jne 1f\n\t"
- "movl $32, %0\n"
- "1:"
- : "=r" (set)
- : "r" (~(*p >> bit)));
- if (set < (32 - bit))
- return set + offset;
- set = 32 - bit;
- p++;
- }
- /*
- * No zero yet, search remaining full bytes for a zero
- */
- res = find_first_zero_bit(p, size - 32 * (p - addr));
- return (offset + set + res);
-}
-EXPORT_SYMBOL(find_next_zero_bit);
diff --git a/arch/x86/lib/bitops_64.c b/arch/x86/lib/bitops_64.c
index 0e8f491e6ccc..0eeb704d2513 100644
--- a/arch/x86/lib/bitops_64.c
+++ b/arch/x86/lib/bitops_64.c
@@ -1,9 +1,7 @@
#include <linux/bitops.h>
#undef find_first_zero_bit
-#undef find_next_zero_bit
#undef find_first_bit
-#undef find_next_bit
static inline long
__find_first_zero_bit(const unsigned long * addr, unsigned long size)
@@ -57,39 +55,6 @@ long find_first_zero_bit(const unsigned long * addr, unsigned long size)
return __find_first_zero_bit (addr, size);
}
-/**
- * find_next_zero_bit - find the next zero bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bitnumber to start searching at
- * @size: The maximum size to search
- */
-long find_next_zero_bit (const unsigned long * addr, long size, long offset)
-{
- const unsigned long * p = addr + (offset >> 6);
- unsigned long set = 0;
- unsigned long res, bit = offset&63;
-
- if (bit) {
- /*
- * Look for zero in first word
- */
- asm("bsfq %1,%0\n\t"
- "cmoveq %2,%0"
- : "=r" (set)
- : "r" (~(*p >> bit)), "r"(64L));
- if (set < (64 - bit))
- return set + offset;
- set = 64 - bit;
- p++;
- }
- /*
- * No zero yet, search remaining full words for a zero
- */
- res = __find_first_zero_bit (p, size - 64 * (p - addr));
-
- return (offset + set + res);
-}
-
static inline long
__find_first_bit(const unsigned long * addr, unsigned long size)
{
@@ -136,40 +101,7 @@ long find_first_bit(const unsigned long * addr, unsigned long size)
return __find_first_bit(addr,size);
}
-/**
- * find_next_bit - find the first set bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bitnumber to start searching at
- * @size: The maximum size to search
- */
-long find_next_bit(const unsigned long * addr, long size, long offset)
-{
- const unsigned long * p = addr + (offset >> 6);
- unsigned long set = 0, bit = offset & 63, res;
-
- if (bit) {
- /*
- * Look for nonzero in the first 64 bits:
- */
- asm("bsfq %1,%0\n\t"
- "cmoveq %2,%0\n\t"
- : "=r" (set)
- : "r" (*p >> bit), "r" (64L));
- if (set < (64 - bit))
- return set + offset;
- set = 64 - bit;
- p++;
- }
- /*
- * No set bit yet, search remaining full words for a bit
- */
- res = __find_first_bit (p, size - 64 * (p - addr));
- return (offset + set + res);
-}
-
#include <linux/module.h>
-EXPORT_SYMBOL(find_next_bit);
EXPORT_SYMBOL(find_first_bit);
EXPORT_SYMBOL(find_first_zero_bit);
-EXPORT_SYMBOL(find_next_zero_bit);
diff --git a/include/asm-x86/bitops.h b/include/asm-x86/bitops.h
index 1ae7b270a1ef..31e408de90c6 100644
--- a/include/asm-x86/bitops.h
+++ b/include/asm-x86/bitops.h
@@ -306,6 +306,12 @@ static int test_bit(int nr, const volatile unsigned long *addr);
#undef BIT_ADDR
#undef ADDR
+unsigned long find_next_bit(const unsigned long *addr,
+ unsigned long size, unsigned long offset);
+unsigned long find_next_zero_bit(const unsigned long *addr,
+ unsigned long size, unsigned long offset);
+
+
#ifdef CONFIG_X86_32
# include "bitops_32.h"
#else
diff --git a/include/asm-x86/bitops_32.h b/include/asm-x86/bitops_32.h
index 2513a81f82aa..7c9ed759afb2 100644
--- a/include/asm-x86/bitops_32.h
+++ b/include/asm-x86/bitops_32.h
@@ -39,14 +39,6 @@ static inline int find_first_zero_bit(const unsigned long *addr, unsigned size)
return res;
}
-/**
- * find_next_zero_bit - find the first zero bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bit number to start searching at
- * @size: The maximum size to search
- */
-int find_next_zero_bit(const unsigned long *addr, int size, int offset);
-
/**
* __ffs - find first bit in word.
* @word: The word to search
@@ -82,14 +74,6 @@ static inline unsigned find_first_bit(const unsigned long *addr, unsigned size)
return x;
}
-/**
- * find_next_bit - find the first set bit in a memory region
- * @addr: The address to base the search on
- * @offset: The bit number to start searching at
- * @size: The maximum size to search
- */
-int find_next_bit(const unsigned long *addr, int size, int offset);
-
/**
* ffz - find first zero in word.
* @word: The word to search
diff --git a/include/asm-x86/bitops_64.h b/include/asm-x86/bitops_64.h
index 365f8207ea59..65b20fb2ae78 100644
--- a/include/asm-x86/bitops_64.h
+++ b/include/asm-x86/bitops_64.h
@@ -6,9 +6,7 @@
*/
extern long find_first_zero_bit(const unsigned long *addr, unsigned long size);
-extern long find_next_zero_bit(const unsigned long *addr, long size, long offset);
extern long find_first_bit(const unsigned long *addr, unsigned long size);
-extern long find_next_bit(const unsigned long *addr, long size, long offset);
/* return index of first bet set in val or max when no bit is set */
static inline long __scanbit(unsigned long val, unsigned long max)
diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
index 78ccd73a8841..5820e072b890 100644
--- a/lib/find_next_bit.c
+++ b/lib/find_next_bit.c
@@ -15,6 +15,8 @@
#include <asm/byteorder.h>
#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
+#undef find_next_bit
+#undef find_next_zero_bit
/**
* find_next_bit - find the next set bit in a memory region