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kernel-ark/include/asm-parisc/bitops.h
Grant Grundler a366064c3f [PARISC] Update bitops from parisc tree 
Optimize ext2_find_next_zero_bit. Gives about 25% perf improvement with a
rsync test with ext3.

Signed-off-by: Randolph Chung <tausq@parisc-linux.org>

fix ext3 performance - ext2_find_next_zero() was culprit.
Kudos to jejb for pointing out the the possibility that ext2_test_bit
and ext2_find_next_zero() may in fact not be enumerating bits in
the bitmap because of endianess. Took sparc64 implementation and
adapted it to our tree. I suspect the real problem is ffz() wants
an unsigned long and was getting garbage in the top half of the
unsigned int. Not confirmed but that's what I suspect.

Signed-off-by: Grant Grundler <grundler@parisc-linux.org>

Fix find_next_bit for 32-bit
Make masking consistent for bitops

From: Joel Soete <soete.joel@tiscali.be>
Signed-off-by: Randolph Chung <tausq@parisc-linux.org>

Add back incorrectly removed ext2_find_first_zero_bit definition

Signed-off-by: James Bottomley <jejb@parisc-linux.org>

Fixup bitops.h to use volatile for *_bit() ops

Based on this email thread:
       http://marc.theaimsgroup.com/?t=108826637900003

In a nutshell:
        *_bit() want use of volatile.
        __*_bit() are "relaxed" and don't use spinlock or volatile.

other minor changes:
o replaces hweight64() macro with alias to generic_hweight64() (Joel Soete)
o cleanup ext2* macros so (a) it's obvious what the XOR magic is about
  and (b) one version that works for both 32/64-bit.
o replace 2 uses of CONFIG_64BIT with __LP64__. bitops.h used both.
  I think header files that might go to user space should use
  something userspace will know about (__LP64__).

Signed-off-by: Grant Grundler <grundler@parisc-linux.org>

Move SHIFT_PER_LONG to standard location for BITS_PER_LONG (asm/types.h)
and ditch the second definition of BITS_PER_LONG in bitops.h

Signed-off-by: Grant Grundler <grundler@parisc-linux.org>

Signed-off-by: Kyle McMartin <kyle@parisc-linux.org>
2005-10-21 22:45:22 -04:00

495 lines
13 KiB
C
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#ifndef _PARISC_BITOPS_H
#define _PARISC_BITOPS_H
#include <linux/compiler.h>
#include <asm/types.h> /* for BITS_PER_LONG/SHIFT_PER_LONG */
#include <asm/byteorder.h>
#include <asm/atomic.h>
/*
* HP-PARISC specific bit operations
* for a detailed description of the functions please refer
* to include/asm-i386/bitops.h or kerneldoc
*/
#define CHOP_SHIFTCOUNT(x) (((unsigned long) (x)) & (BITS_PER_LONG - 1))
#define smp_mb__before_clear_bit() smp_mb()
#define smp_mb__after_clear_bit() smp_mb()
/* See http://marc.theaimsgroup.com/?t=108826637900003 for discussion
* on use of volatile and __*_bit() (set/clear/change):
* *_bit() want use of volatile.
* __*_bit() are "relaxed" and don't use spinlock or volatile.
*/
static __inline__ void set_bit(int nr, volatile unsigned long * addr)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
_atomic_spin_lock_irqsave(addr, flags);
*addr |= mask;
_atomic_spin_unlock_irqrestore(addr, flags);
}
static __inline__ void __set_bit(unsigned long nr, volatile unsigned long * addr)
{
unsigned long *m = (unsigned long *) addr + (nr >> SHIFT_PER_LONG);
*m |= 1UL << CHOP_SHIFTCOUNT(nr);
}
static __inline__ void clear_bit(int nr, volatile unsigned long * addr)
{
unsigned long mask = ~(1UL << CHOP_SHIFTCOUNT(nr));
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
_atomic_spin_lock_irqsave(addr, flags);
*addr &= mask;
_atomic_spin_unlock_irqrestore(addr, flags);
}
static __inline__ void __clear_bit(unsigned long nr, volatile unsigned long * addr)
{
unsigned long *m = (unsigned long *) addr + (nr >> SHIFT_PER_LONG);
*m &= ~(1UL << CHOP_SHIFTCOUNT(nr));
}
static __inline__ void change_bit(int nr, volatile unsigned long * addr)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
_atomic_spin_lock_irqsave(addr, flags);
*addr ^= mask;
_atomic_spin_unlock_irqrestore(addr, flags);
}
static __inline__ void __change_bit(unsigned long nr, volatile unsigned long * addr)
{
unsigned long *m = (unsigned long *) addr + (nr >> SHIFT_PER_LONG);
*m ^= 1UL << CHOP_SHIFTCOUNT(nr);
}
static __inline__ int test_and_set_bit(int nr, volatile unsigned long * addr)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long oldbit;
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
_atomic_spin_lock_irqsave(addr, flags);
oldbit = *addr;
*addr = oldbit | mask;
_atomic_spin_unlock_irqrestore(addr, flags);
return (oldbit & mask) ? 1 : 0;
}
static __inline__ int __test_and_set_bit(int nr, volatile unsigned long * address)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long oldbit;
unsigned long *addr = (unsigned long *)address + (nr >> SHIFT_PER_LONG);
oldbit = *addr;
*addr = oldbit | mask;
return (oldbit & mask) ? 1 : 0;
}
static __inline__ int test_and_clear_bit(int nr, volatile unsigned long * addr)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long oldbit;
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
_atomic_spin_lock_irqsave(addr, flags);
oldbit = *addr;
*addr = oldbit & ~mask;
_atomic_spin_unlock_irqrestore(addr, flags);
return (oldbit & mask) ? 1 : 0;
}
static __inline__ int __test_and_clear_bit(int nr, volatile unsigned long * address)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long *addr = (unsigned long *)address + (nr >> SHIFT_PER_LONG);
unsigned long oldbit;
oldbit = *addr;
*addr = oldbit & ~mask;
return (oldbit & mask) ? 1 : 0;
}
static __inline__ int test_and_change_bit(int nr, volatile unsigned long * addr)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long oldbit;
unsigned long flags;
addr += (nr >> SHIFT_PER_LONG);
_atomic_spin_lock_irqsave(addr, flags);
oldbit = *addr;
*addr = oldbit ^ mask;
_atomic_spin_unlock_irqrestore(addr, flags);
return (oldbit & mask) ? 1 : 0;
}
static __inline__ int __test_and_change_bit(int nr, volatile unsigned long * address)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
unsigned long *addr = (unsigned long *)address + (nr >> SHIFT_PER_LONG);
unsigned long oldbit;
oldbit = *addr;
*addr = oldbit ^ mask;
return (oldbit & mask) ? 1 : 0;
}
static __inline__ int test_bit(int nr, const volatile unsigned long *address)
{
unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
const unsigned long *addr = (const unsigned long *)address + (nr >> SHIFT_PER_LONG);
return !!(*addr & mask);
}
#ifdef __KERNEL__
/**
* __ffs - find first bit in word. returns 0 to "BITS_PER_LONG-1".
* @word: The word to search
*
* __ffs() return is undefined if no bit is set.
*
* 32-bit fast __ffs by LaMont Jones "lamont At hp com".
* 64-bit enhancement by Grant Grundler "grundler At parisc-linux org".
* (with help from willy/jejb to get the semantics right)
*
* This algorithm avoids branches by making use of nullification.
* One side effect of "extr" instructions is it sets PSW[N] bit.
* How PSW[N] (nullify next insn) gets set is determined by the
* "condition" field (eg "<>" or "TR" below) in the extr* insn.
* Only the 1st and one of either the 2cd or 3rd insn will get executed.
* Each set of 3 insn will get executed in 2 cycles on PA8x00 vs 16 or so
* cycles for each mispredicted branch.
*/
static __inline__ unsigned long __ffs(unsigned long x)
{
unsigned long ret;
__asm__(
#ifdef __LP64__
" ldi 63,%1\n"
" extrd,u,*<> %0,63,32,%%r0\n"
" extrd,u,*TR %0,31,32,%0\n" /* move top 32-bits down */
" addi -32,%1,%1\n"
#else
" ldi 31,%1\n"
#endif
" extru,<> %0,31,16,%%r0\n"
" extru,TR %0,15,16,%0\n" /* xxxx0000 -> 0000xxxx */
" addi -16,%1,%1\n"
" extru,<> %0,31,8,%%r0\n"
" extru,TR %0,23,8,%0\n" /* 0000xx00 -> 000000xx */
" addi -8,%1,%1\n"
" extru,<> %0,31,4,%%r0\n"
" extru,TR %0,27,4,%0\n" /* 000000x0 -> 0000000x */
" addi -4,%1,%1\n"
" extru,<> %0,31,2,%%r0\n"
" extru,TR %0,29,2,%0\n" /* 0000000y, 1100b -> 0011b */
" addi -2,%1,%1\n"
" extru,= %0,31,1,%%r0\n" /* check last bit */
" addi -1,%1,%1\n"
: "+r" (x), "=r" (ret) );
return ret;
}
/* Undefined if no bit is zero. */
#define ffz(x) __ffs(~x)
/*
* ffs: find first bit set. returns 1 to BITS_PER_LONG or 0 (if none set)
* This is defined the same way as the libc and compiler builtin
* ffs routines, therefore differs in spirit from the above ffz (man ffs).
*/
static __inline__ int ffs(int x)
{
return x ? (__ffs((unsigned long)x) + 1) : 0;
}
/*
* fls: find last (most significant) bit set.
* fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
*/
static __inline__ int fls(int x)
{
int ret;
if (!x)
return 0;
__asm__(
" ldi 1,%1\n"
" extru,<> %0,15,16,%%r0\n"
" zdep,TR %0,15,16,%0\n" /* xxxx0000 */
" addi 16,%1,%1\n"
" extru,<> %0,7,8,%%r0\n"
" zdep,TR %0,23,24,%0\n" /* xx000000 */
" addi 8,%1,%1\n"
" extru,<> %0,3,4,%%r0\n"
" zdep,TR %0,27,28,%0\n" /* x0000000 */
" addi 4,%1,%1\n"
" extru,<> %0,1,2,%%r0\n"
" zdep,TR %0,29,30,%0\n" /* y0000000 (y&3 = 0) */
" addi 2,%1,%1\n"
" extru,= %0,0,1,%%r0\n"
" addi 1,%1,%1\n" /* if y & 8, add 1 */
: "+r" (x), "=r" (ret) );
return ret;
}
/*
* hweightN: returns the hamming weight (i.e. the number
* of bits set) of a N-bit word
*/
#define hweight64(x) generic_hweight64(x)
#define hweight32(x) generic_hweight32(x)
#define hweight16(x) generic_hweight16(x)
#define hweight8(x) generic_hweight8(x)
/*
* Every architecture must define this function. It's the fastest
* way of searching a 140-bit bitmap where the first 100 bits are
* unlikely to be set. It's guaranteed that at least one of the 140
* bits is cleared.
*/
static inline int sched_find_first_bit(const unsigned long *b)
{
#ifdef __LP64__
if (unlikely(b[0]))
return __ffs(b[0]);
if (unlikely(b[1]))
return __ffs(b[1]) + 64;
return __ffs(b[2]) + 128;
#else
if (unlikely(b[0]))
return __ffs(b[0]);
if (unlikely(b[1]))
return __ffs(b[1]) + 32;
if (unlikely(b[2]))
return __ffs(b[2]) + 64;
if (b[3])
return __ffs(b[3]) + 96;
return __ffs(b[4]) + 128;
#endif
}
#endif /* __KERNEL__ */
/*
* This implementation of find_{first,next}_zero_bit was stolen from
* Linus' asm-alpha/bitops.h.
*/
#define find_first_zero_bit(addr, size) \
find_next_zero_bit((addr), (size), 0)
static __inline__ unsigned long find_next_zero_bit(const void * addr, unsigned long size, unsigned long offset)
{
const unsigned long * p = ((unsigned long *) addr) + (offset >> SHIFT_PER_LONG);
unsigned long result = offset & ~(BITS_PER_LONG-1);
unsigned long tmp;
if (offset >= size)
return size;
size -= result;
offset &= (BITS_PER_LONG-1);
if (offset) {
tmp = *(p++);
tmp |= ~0UL >> (BITS_PER_LONG-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 (!size)
return result;
tmp = *p;
found_first:
tmp |= ~0UL << size;
found_middle:
return result + ffz(tmp);
}
static __inline__ unsigned long find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset)
{
const unsigned long *p = addr + (offset >> SHIFT_PER_LONG);
unsigned long result = offset & ~(BITS_PER_LONG-1);
unsigned long tmp;
if (offset >= size)
return size;
size -= result;
offset &= (BITS_PER_LONG-1);
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 (!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);
}
/**
* find_first_bit - find the first set bit in a memory region
* @addr: The address to start the search at
* @size: The maximum size to search
*
* Returns the bit-number of the first set bit, not the number of the byte
* containing a bit.
*/
#define find_first_bit(addr, size) \
find_next_bit((addr), (size), 0)
#define _EXT2_HAVE_ASM_BITOPS_
#ifdef __KERNEL__
/*
* test_and_{set,clear}_bit guarantee atomicity without
* disabling interrupts.
*/
/* '3' is bits per byte */
#define LE_BYTE_ADDR ((sizeof(unsigned long) - 1) << 3)
#define ext2_test_bit(nr, addr) \
test_bit((nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
#define ext2_set_bit(nr, addr) \
__test_and_set_bit((nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
#define ext2_clear_bit(nr, addr) \
__test_and_clear_bit((nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
#define ext2_set_bit_atomic(l,nr,addr) \
test_and_set_bit((nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
#define ext2_clear_bit_atomic(l,nr,addr) \
test_and_clear_bit( (nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
#endif /* __KERNEL__ */
#define ext2_find_first_zero_bit(addr, size) \
ext2_find_next_zero_bit((addr), (size), 0)
/* include/linux/byteorder does not support "unsigned long" type */
static inline unsigned long ext2_swabp(unsigned long * x)
{
#ifdef __LP64__
return (unsigned long) __swab64p((u64 *) x);
#else
return (unsigned long) __swab32p((u32 *) x);
#endif
}
/* include/linux/byteorder doesn't support "unsigned long" type */
static inline unsigned long ext2_swab(unsigned long y)
{
#ifdef __LP64__
return (unsigned long) __swab64((u64) y);
#else
return (unsigned long) __swab32((u32) y);
#endif
}
static __inline__ unsigned long ext2_find_next_zero_bit(void *addr, unsigned long size, unsigned long offset)
{
unsigned long *p = (unsigned long *) addr + (offset >> SHIFT_PER_LONG);
unsigned long result = offset & ~(BITS_PER_LONG - 1);
unsigned long tmp;
if (offset >= size)
return size;
size -= result;
offset &= (BITS_PER_LONG - 1UL);
if (offset) {
tmp = ext2_swabp(p++);
tmp |= (~0UL >> (BITS_PER_LONG - 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_swap;
result += BITS_PER_LONG;
size -= BITS_PER_LONG;
}
if (!size)
return result;
tmp = ext2_swabp(p);
found_first:
tmp |= ~0UL << size;
if (tmp == ~0UL) /* Are any bits zero? */
return result + size; /* Nope. Skip ffz */
found_middle:
return result + ffz(tmp);
found_middle_swap:
return result + ffz(ext2_swab(tmp));
}
/* Bitmap functions for the minix filesystem. */
#define minix_test_and_set_bit(nr,addr) ext2_set_bit(nr,addr)
#define minix_set_bit(nr,addr) ((void)ext2_set_bit(nr,addr))
#define minix_test_and_clear_bit(nr,addr) ext2_clear_bit(nr,addr)
#define minix_test_bit(nr,addr) ext2_test_bit(nr,addr)
#define minix_find_first_zero_bit(addr,size) ext2_find_first_zero_bit(addr,size)
#endif /* _PARISC_BITOPS_H */
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