a366064c3f
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>
494 lines
13 KiB
C
494 lines
13 KiB
C
#ifndef _PARISC_BITOPS_H
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#define _PARISC_BITOPS_H
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#include <linux/compiler.h>
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#include <asm/types.h> /* for BITS_PER_LONG/SHIFT_PER_LONG */
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#include <asm/byteorder.h>
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#include <asm/atomic.h>
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/*
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* HP-PARISC specific bit operations
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* for a detailed description of the functions please refer
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* to include/asm-i386/bitops.h or kerneldoc
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*/
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#define CHOP_SHIFTCOUNT(x) (((unsigned long) (x)) & (BITS_PER_LONG - 1))
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#define smp_mb__before_clear_bit() smp_mb()
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#define smp_mb__after_clear_bit() smp_mb()
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/* See http://marc.theaimsgroup.com/?t=108826637900003 for discussion
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* on use of volatile and __*_bit() (set/clear/change):
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* *_bit() want use of volatile.
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* __*_bit() are "relaxed" and don't use spinlock or volatile.
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*/
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static __inline__ void set_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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*addr |= mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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}
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static __inline__ void __set_bit(unsigned long nr, volatile unsigned long * addr)
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{
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unsigned long *m = (unsigned long *) addr + (nr >> SHIFT_PER_LONG);
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*m |= 1UL << CHOP_SHIFTCOUNT(nr);
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}
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static __inline__ void clear_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = ~(1UL << CHOP_SHIFTCOUNT(nr));
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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*addr &= mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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}
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static __inline__ void __clear_bit(unsigned long nr, volatile unsigned long * addr)
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{
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unsigned long *m = (unsigned long *) addr + (nr >> SHIFT_PER_LONG);
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*m &= ~(1UL << CHOP_SHIFTCOUNT(nr));
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}
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static __inline__ void change_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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*addr ^= mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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}
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static __inline__ void __change_bit(unsigned long nr, volatile unsigned long * addr)
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{
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unsigned long *m = (unsigned long *) addr + (nr >> SHIFT_PER_LONG);
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*m ^= 1UL << CHOP_SHIFTCOUNT(nr);
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}
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static __inline__ int test_and_set_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long oldbit;
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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oldbit = *addr;
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*addr = oldbit | mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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return (oldbit & mask) ? 1 : 0;
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}
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static __inline__ int __test_and_set_bit(int nr, volatile unsigned long * address)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long oldbit;
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unsigned long *addr = (unsigned long *)address + (nr >> SHIFT_PER_LONG);
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oldbit = *addr;
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*addr = oldbit | mask;
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return (oldbit & mask) ? 1 : 0;
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}
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static __inline__ int test_and_clear_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long oldbit;
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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oldbit = *addr;
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*addr = oldbit & ~mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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return (oldbit & mask) ? 1 : 0;
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}
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static __inline__ int __test_and_clear_bit(int nr, volatile unsigned long * address)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long *addr = (unsigned long *)address + (nr >> SHIFT_PER_LONG);
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unsigned long oldbit;
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oldbit = *addr;
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*addr = oldbit & ~mask;
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return (oldbit & mask) ? 1 : 0;
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}
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static __inline__ int test_and_change_bit(int nr, volatile unsigned long * addr)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long oldbit;
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unsigned long flags;
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addr += (nr >> SHIFT_PER_LONG);
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_atomic_spin_lock_irqsave(addr, flags);
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oldbit = *addr;
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*addr = oldbit ^ mask;
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_atomic_spin_unlock_irqrestore(addr, flags);
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return (oldbit & mask) ? 1 : 0;
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}
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static __inline__ int __test_and_change_bit(int nr, volatile unsigned long * address)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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unsigned long *addr = (unsigned long *)address + (nr >> SHIFT_PER_LONG);
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unsigned long oldbit;
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oldbit = *addr;
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*addr = oldbit ^ mask;
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return (oldbit & mask) ? 1 : 0;
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}
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static __inline__ int test_bit(int nr, const volatile unsigned long *address)
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{
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unsigned long mask = 1UL << CHOP_SHIFTCOUNT(nr);
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const unsigned long *addr = (const unsigned long *)address + (nr >> SHIFT_PER_LONG);
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return !!(*addr & mask);
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}
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#ifdef __KERNEL__
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/**
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* __ffs - find first bit in word. returns 0 to "BITS_PER_LONG-1".
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* @word: The word to search
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*
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* __ffs() return is undefined if no bit is set.
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*
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* 32-bit fast __ffs by LaMont Jones "lamont At hp com".
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* 64-bit enhancement by Grant Grundler "grundler At parisc-linux org".
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* (with help from willy/jejb to get the semantics right)
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*
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* This algorithm avoids branches by making use of nullification.
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* One side effect of "extr" instructions is it sets PSW[N] bit.
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* How PSW[N] (nullify next insn) gets set is determined by the
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* "condition" field (eg "<>" or "TR" below) in the extr* insn.
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* Only the 1st and one of either the 2cd or 3rd insn will get executed.
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* Each set of 3 insn will get executed in 2 cycles on PA8x00 vs 16 or so
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* cycles for each mispredicted branch.
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*/
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static __inline__ unsigned long __ffs(unsigned long x)
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{
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unsigned long ret;
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__asm__(
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#ifdef __LP64__
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" ldi 63,%1\n"
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" extrd,u,*<> %0,63,32,%%r0\n"
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" extrd,u,*TR %0,31,32,%0\n" /* move top 32-bits down */
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" addi -32,%1,%1\n"
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#else
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" ldi 31,%1\n"
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#endif
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" extru,<> %0,31,16,%%r0\n"
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" extru,TR %0,15,16,%0\n" /* xxxx0000 -> 0000xxxx */
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" addi -16,%1,%1\n"
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" extru,<> %0,31,8,%%r0\n"
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" extru,TR %0,23,8,%0\n" /* 0000xx00 -> 000000xx */
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" addi -8,%1,%1\n"
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" extru,<> %0,31,4,%%r0\n"
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" extru,TR %0,27,4,%0\n" /* 000000x0 -> 0000000x */
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" addi -4,%1,%1\n"
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" extru,<> %0,31,2,%%r0\n"
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" extru,TR %0,29,2,%0\n" /* 0000000y, 1100b -> 0011b */
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" addi -2,%1,%1\n"
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" extru,= %0,31,1,%%r0\n" /* check last bit */
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" addi -1,%1,%1\n"
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: "+r" (x), "=r" (ret) );
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return ret;
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}
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/* Undefined if no bit is zero. */
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#define ffz(x) __ffs(~x)
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/*
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* ffs: find first bit set. returns 1 to BITS_PER_LONG or 0 (if none set)
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* This is defined the same way as the libc and compiler builtin
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* ffs routines, therefore differs in spirit from the above ffz (man ffs).
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*/
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static __inline__ int ffs(int x)
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{
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return x ? (__ffs((unsigned long)x) + 1) : 0;
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}
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/*
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* fls: find last (most significant) bit set.
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* fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
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*/
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static __inline__ int fls(int x)
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{
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int ret;
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if (!x)
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return 0;
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__asm__(
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" ldi 1,%1\n"
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" extru,<> %0,15,16,%%r0\n"
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" zdep,TR %0,15,16,%0\n" /* xxxx0000 */
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" addi 16,%1,%1\n"
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" extru,<> %0,7,8,%%r0\n"
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" zdep,TR %0,23,24,%0\n" /* xx000000 */
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" addi 8,%1,%1\n"
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" extru,<> %0,3,4,%%r0\n"
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" zdep,TR %0,27,28,%0\n" /* x0000000 */
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" addi 4,%1,%1\n"
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" extru,<> %0,1,2,%%r0\n"
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" zdep,TR %0,29,30,%0\n" /* y0000000 (y&3 = 0) */
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" addi 2,%1,%1\n"
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" extru,= %0,0,1,%%r0\n"
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" addi 1,%1,%1\n" /* if y & 8, add 1 */
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: "+r" (x), "=r" (ret) );
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return ret;
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}
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/*
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* hweightN: returns the hamming weight (i.e. the number
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* of bits set) of a N-bit word
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*/
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#define hweight64(x) generic_hweight64(x)
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#define hweight32(x) generic_hweight32(x)
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#define hweight16(x) generic_hweight16(x)
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#define hweight8(x) generic_hweight8(x)
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/*
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* Every architecture must define this function. It's the fastest
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* way of searching a 140-bit bitmap where the first 100 bits are
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* unlikely to be set. It's guaranteed that at least one of the 140
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* bits is cleared.
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*/
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static inline int sched_find_first_bit(const unsigned long *b)
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{
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#ifdef __LP64__
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if (unlikely(b[0]))
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return __ffs(b[0]);
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if (unlikely(b[1]))
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return __ffs(b[1]) + 64;
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return __ffs(b[2]) + 128;
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#else
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if (unlikely(b[0]))
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return __ffs(b[0]);
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if (unlikely(b[1]))
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return __ffs(b[1]) + 32;
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if (unlikely(b[2]))
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return __ffs(b[2]) + 64;
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if (b[3])
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return __ffs(b[3]) + 96;
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return __ffs(b[4]) + 128;
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#endif
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}
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#endif /* __KERNEL__ */
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/*
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* This implementation of find_{first,next}_zero_bit was stolen from
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* Linus' asm-alpha/bitops.h.
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*/
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#define find_first_zero_bit(addr, size) \
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find_next_zero_bit((addr), (size), 0)
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static __inline__ unsigned long find_next_zero_bit(const void * addr, unsigned long size, unsigned long offset)
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{
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const unsigned long * p = ((unsigned long *) addr) + (offset >> SHIFT_PER_LONG);
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unsigned long result = offset & ~(BITS_PER_LONG-1);
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= (BITS_PER_LONG-1);
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if (offset) {
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tmp = *(p++);
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tmp |= ~0UL >> (BITS_PER_LONG-offset);
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if (size < BITS_PER_LONG)
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goto found_first;
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if (~tmp)
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goto found_middle;
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size -= BITS_PER_LONG;
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result += BITS_PER_LONG;
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}
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while (size & ~(BITS_PER_LONG -1)) {
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if (~(tmp = *(p++)))
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goto found_middle;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp |= ~0UL << size;
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found_middle:
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return result + ffz(tmp);
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}
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static __inline__ unsigned long find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset)
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{
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const unsigned long *p = addr + (offset >> SHIFT_PER_LONG);
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unsigned long result = offset & ~(BITS_PER_LONG-1);
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= (BITS_PER_LONG-1);
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if (offset) {
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tmp = *(p++);
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tmp &= (~0UL << offset);
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if (size < BITS_PER_LONG)
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goto found_first;
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if (tmp)
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goto found_middle;
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size -= BITS_PER_LONG;
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result += BITS_PER_LONG;
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}
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while (size & ~(BITS_PER_LONG-1)) {
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if ((tmp = *(p++)))
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goto found_middle;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = *p;
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found_first:
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tmp &= (~0UL >> (BITS_PER_LONG - size));
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if (tmp == 0UL) /* Are any bits set? */
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return result + size; /* Nope. */
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found_middle:
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return result + __ffs(tmp);
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}
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/**
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* find_first_bit - find the first set bit in a memory region
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* @addr: The address to start the search at
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* @size: The maximum size to search
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*
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* Returns the bit-number of the first set bit, not the number of the byte
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* containing a bit.
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*/
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#define find_first_bit(addr, size) \
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find_next_bit((addr), (size), 0)
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#define _EXT2_HAVE_ASM_BITOPS_
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#ifdef __KERNEL__
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/*
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* test_and_{set,clear}_bit guarantee atomicity without
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* disabling interrupts.
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*/
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/* '3' is bits per byte */
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#define LE_BYTE_ADDR ((sizeof(unsigned long) - 1) << 3)
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#define ext2_test_bit(nr, addr) \
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test_bit((nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
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#define ext2_set_bit(nr, addr) \
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__test_and_set_bit((nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
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#define ext2_clear_bit(nr, addr) \
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__test_and_clear_bit((nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
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#define ext2_set_bit_atomic(l,nr,addr) \
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test_and_set_bit((nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
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#define ext2_clear_bit_atomic(l,nr,addr) \
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test_and_clear_bit( (nr) ^ LE_BYTE_ADDR, (unsigned long *)addr)
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#endif /* __KERNEL__ */
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#define ext2_find_first_zero_bit(addr, size) \
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ext2_find_next_zero_bit((addr), (size), 0)
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/* include/linux/byteorder does not support "unsigned long" type */
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static inline unsigned long ext2_swabp(unsigned long * x)
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{
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#ifdef __LP64__
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return (unsigned long) __swab64p((u64 *) x);
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#else
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return (unsigned long) __swab32p((u32 *) x);
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#endif
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}
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/* include/linux/byteorder doesn't support "unsigned long" type */
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static inline unsigned long ext2_swab(unsigned long y)
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{
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#ifdef __LP64__
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return (unsigned long) __swab64((u64) y);
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#else
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return (unsigned long) __swab32((u32) y);
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#endif
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}
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static __inline__ unsigned long ext2_find_next_zero_bit(void *addr, unsigned long size, unsigned long offset)
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{
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unsigned long *p = (unsigned long *) addr + (offset >> SHIFT_PER_LONG);
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unsigned long result = offset & ~(BITS_PER_LONG - 1);
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= (BITS_PER_LONG - 1UL);
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if (offset) {
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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 */
|