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atomic.h
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atomic.h
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/*
* Aerospike Foundation
* include/atomic.h - atomic memory operations
*
* Copyright (c) 2008-2012 Aerospike, Inc. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy of
* this software and associated documentation files (the "Software"), to deal in
* the Software without restriction, including without limitation the rights to
* use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
* of the Software, and to permit persons to whom the Software is furnished to do
* so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
*/
#pragma once
#include <stdint.h>
/* SYNOPSIS
* Atomic memory operations
* Memory barriers
* > */
#define MARCH_x86_64
/* Atomic memory operations */
/* cf_atomic64
* An implementation of an atomic 64-bit data type
* NB: some older compilers may exhibit aliasing bugs that require this
* definition to be wrapped in a structure */
#ifdef MARCH_i686
typedef volatile uint32_t cf_atomic32;
typedef volatile uint32_t cf_atomic_p;
typedef volatile uint32_t cf_atomic_int;
#define SIZEOF_ATOMIC_INT 4
typedef uint32_t cf_atomic_int_t; // the point here is a type of the same size as cf_atomic_int but isn't atomic
#define HAS_ATOMIC_32 1
#endif
#ifdef MARCH_x86_64
typedef volatile uint64_t cf_atomic64;
typedef volatile uint32_t cf_atomic32;
typedef volatile uint64_t cf_atomic_p;
typedef volatile uint64_t cf_atomic_int;
#define SIZEOF_ATOMIC_INT 8
typedef uint64_t cf_atomic_int_t; // the point here is a type of the same size as cf_atomic_int but isn't atomic
#define HAS_ATOMIC_32 1
#define HAS_ATOMIC_64 1
#endif
/*
* cf_atomicX_add
* Atomic addition: add a value b into an atomic integer a, and return the result
*
* cf_atomicX_cas
* Compare-and-swap: test a value b against an atomic integer a; if they
* are equal, store the value x into a, and return the initial value of a.
* "Success" can be checked by comparing the returned value against b
* NB: this is a strong memory barrier
*
* cf_atomicX_fas
* Fetch-and-swap: swap the values of b and a
*
* cf_atomicX_addunless
* Increment-unless: test a value b against an atomic integer a. If they
* are NOT equal, add x to a, and return non-zero; if they ARE equal, return
* zero
*/
/* cf_atomic64_get
* Read an atomic value */
#ifdef HAS_ATOMIC_64
#define cf_atomic64_get(a) (a)
#define cf_atomic64_set(a, b) (*(a) = (b))
static inline int64_t
cf_atomic64_add(cf_atomic64 *a, int64_t b)
{
int64_t i = b;
__asm__ __volatile__ ("lock; xaddq %0, %1" : "+r" (b), "+m" (*a) : : "memory");
return(b + i);
}
#define cf_atomic64_sub(a,b) (cf_atomic64_add((a), (0 - (b))))
#define cf_atomic64_incr(a) (cf_atomic64_add((a), 1))
#define cf_atomic64_decr(a) (cf_atomic64_add((a), -1))
static inline int64_t
cf_atomic64_cas(cf_atomic64 *a, int64_t b, int64_t x)
{
int64_t p;
__asm__ __volatile__ ("lock; cmpxchgq %1,%2" : "=a"(p) : "q"(x), "m"(*(a)), "0"(b) : "memory");
return(p);
}
#define cf_atomic64_cas_m(_a, _b, _x) \
({ __typeof__(_b) __b = _b; \
__asm__ __volatile__ ("lock; cmpxchgq %1,%2" : "=a"(__b) : "q"(_x), "m"(*(_a)), "0"(_b) : "memory"); \
__b; \
})
/* cf_atomic64_fas
* Fetch-and-swap: swap the values of b and a */
static inline int64_t
cf_atomic64_fas(cf_atomic64 *a, cf_atomic64 *b)
{
int64_t p;
__asm__ __volatile__ ("lock; xchgq %0,%1" : "=r"(p) : "m"(*(a)), "0"(*(b)) : "memory");
return(p);
}
#define cf_atomic64_fas_m(_a, _b) \
({ __typeof__(_b) __b; \
__asm__ __volatile__ ("lock; xchgq %0,%1" : "=r"(__b) : "m"(*(_a)), "0"(_b)); \
__b; \
})
static inline int64_t
cf_atomic64_addunless(cf_atomic64 *a, int64_t b, int64_t x)
{
int64_t prior, cur;
/* Get the current value of the atomic integer */
cur = cf_atomic64_get(*a);
for ( ;; ) {
/* Check if the current value is equal to the criterion */
if (cur == b)
break;
/* Attempt a compare-and-swap, which will return the value of cur
* prior to the operation */
prior = cf_atomic64_cas(a, cur, cur + x);
/* If prior and cur are equal, then the operation has succeeded;
* otherwise, set cur to prior and go around again */
if (prior == cur)
break;
cur = prior;
}
return(cur != b);
}
static inline int64_t
cf_atomic64_setmax(cf_atomic64 *a, int64_t x)
{
int64_t prior, cur;
/* Get the current value of the atomic integer */
cur = cf_atomic64_get(*a);
for ( ;; ) {
/* Check if the current value is equal to the criterion */
if (cur >= x)
break;
/* Attempt a compare-and-swap, which will return the value of cur
* prior to the operation */
prior = cf_atomic64_cas(a, cur, x);
/* If prior and cur are equal, then the operation has succeeded;
* otherwise, set cur to prior and go around again */
if (prior == cur)
break;
cur = prior;
}
return(cur != x);
}
#endif // uint64
#ifdef HAS_ATOMIC_32
#define cf_atomic32_get(a) (a)
#define cf_atomic32_set(a, b) (*(a) = (b))
static inline int64_t
cf_atomic32_add(cf_atomic32 *a, int32_t b)
{
int32_t i = b;
__asm__ __volatile__ ("lock; xadd %0, %1" : "+r" (b), "+m" (*a) : : "memory");
return(b + i);
}
#define cf_atomic32_sub(a,b) (cf_atomic32_add((a), (0 - (b))))
#define cf_atomic32_incr(a) (cf_atomic32_add((a), 1))
#define cf_atomic32_decr(a) (cf_atomic32_add((a), -1))
static inline int32_t
cf_atomic32_cas(cf_atomic32 *a, int32_t b, int32_t x)
{
int32_t p;
__asm__ __volatile__ ("lock; cmpxchg %1,%2" : "=a"(p) : "q"(x), "m"(*(a)), "0"(b) : "memory");
return(p);
}
#define cf_atomic32_cas_m(_a, _b, _x) \
({ __typeof__(_b) __b = _b; \
__asm__ __volatile__ ("lock; cmpxchg %1,%2" : "=a"(__b) : "q"(_x), "m"(*(_a)), "0"(_b) : "memory"); \
__b; \
})
/* cf_atomic32_fas
* Fetch-and-swap: swap the values of b and a */
static inline int32_t
cf_atomic32_fas(cf_atomic32 *a, cf_atomic32 *b)
{
int32_t p;
__asm__ __volatile__ ("lock; xchg %0,%1" : "=r"(p) : "m"(*(a)), "0"(*(b)) : "memory");
return(p);
}
#define cf_atomic32_fas_m(_a, _b) \
({ __typeof__(_b) __b; \
__asm__ __volatile__ ("lock; xchg %0,%1" : "=r"(__b) : "m"(*(_a)), "0"(_b)); \
__b; \
})
static inline int32_t
cf_atomic32_addunless(cf_atomic32 *a, int32_t b, int32_t x)
{
int32_t prior, cur;
/* Get the current value of the atomic integer */
cur = cf_atomic32_get(*a);
for ( ;; ) {
/* Check if the current value is equal to the criterion */
if (cur == b)
break;
/* Attempt a compare-and-swap, which will return the value of cur
* prior to the operation */
prior = cf_atomic32_cas(a, cur, cur + x);
/* If prior and cur are equal, then the operation has succeeded;
* otherwise, set cur to prior and go around again */
if (prior == cur)
break;
cur = prior;
}
return(cur != b);
}
static inline int32_t
cf_atomic32_setmax(cf_atomic32 *a, int32_t x)
{
int32_t prior, cur;
/* Get the current value of the atomic integer */
cur = cf_atomic32_get(*a);
for ( ;; ) {
/* Check if the current value is equal to the criterion */
if (cur >= x)
break;
/* Attempt a compare-and-swap, which will return the value of cur
* prior to the operation */
prior = cf_atomic32_cas(a, cur, x);
/* If prior and cur are equal, then the operation has succeeded;
* otherwise, set cur to prior and go around again */
if (prior == cur)
break;
cur = prior;
}
return(cur != x);
}
#endif // uint32
#ifdef MARCH_i686
#define cf_atomic_p_get(_a) cf_atomic32_get(_a)
#define cf_atomic_p_set(_a, _b) cf_atomic32_set(_a, _b)
#define cf_atomic_p_add(_a, _b) cf_atomic32_add(_a, _b)
#define cf_atomic_p_incr(_a) cf_atomic32_add((_a), 1)
#define cf_atomic_p_decr(_a) cf_atomic32_add((_a), -1)
#define cf_atomic_p_cas(_a, _b, _x) cf_atomic32_cas(_a, _b, _x)
#define cf_atomic_p_cas_m(_a, _b, _x) cf_atomic32_cas_m(_a, _b, _x)
#define cf_atomic_p_fas(_a, _b) cf_atomic32_fas(_a, _b)
#define cf_atomic_p_fas_m(_a, _b) cf_atomic32_fas_m(_a, _b)
#define cf_atomic_p_addunless(_a, _b, _x) cf_atomic32_addunless(_a, _b, _x)
#define cf_atomic_p_setmax(_a, _x) cf_atomic32_setmax(_a, _x)
#define cf_atomic_int_get(_a) cf_atomic32_get(_a)
#define cf_atomic_int_set(_a, _b) cf_atomic32_set(_a, _b)
#define cf_atomic_int_add(_a, _b) cf_atomic32_add(_a, _b)
#define cf_atomic_int_sub(_a, _b) cf_atomic32_sub(_a, _b)
#define cf_atomic_int_incr(_a) cf_atomic32_add((_a), 1)
#define cf_atomic_int_decr(_a) cf_atomic32_add((_a), -1)
#define cf_atomic_int_cas(_a, _b, _x) cf_atomic32_cas(_a, _b, _x)
#define cf_atomic_int_cas_m(_a, _b, _x) cf_atomic32_cas_m(_a, _b, _x)
#define cf_atomic_int_fas(_a, _b) cf_atomic32_fas(_a, _b)
#define cf_atomic_int_fas_m(_a, _b) cf_atomic32_fas_m(_a, _b)
#define cf_atomic_int_addunless(_a, _b, _x) cf_atomic32_addunless(_a, _b, _x)
#define cf_atomic_int_setmax(_a, _x) cf_atomic32_setmax(_a, _x)
#endif
#ifdef MARCH_x86_64
#define cf_atomic_p_get(_a) cf_atomic64_get(_a)
#define cf_atomic_p_set(_a, _b) cf_atomic64_set(_a, _b)
#define cf_atomic_p_add(_a, _b) cf_atomic64_add(_a, _b)
#define cf_atomic_p_incr(_a) cf_atomic64_add((_a), 1)
#define cf_atomic_p_decr(_a) cf_atomic64_add((_a), -1)
#define cf_atomic_p_cas(_a, _b, _x) cf_atomic64_cas(_a, _b, _x)
#define cf_atomic_p_cas_m(_a, _b, _x) cf_atomic64_cas_m(_a, _b, _x)
#define cf_atomic_p_fas(_a, _b) cf_atomic64_fas(_a, _b)
#define cf_atomic_p_fas_m(_a, _b) cf_atomic64_fas_m(_a, _b)
#define cf_atomic_p_addunless(_a, _b, _x) cf_atomic64_addunless(_a, _b, _x)
#define cf_atomic_p_setmax(_a, _x) cf_atomic64_setmax(_a, _x)
#define cf_atomic_int_get(_a) cf_atomic64_get(_a)
#define cf_atomic_int_set(_a, _b) cf_atomic64_set(_a, _b)
#define cf_atomic_int_add(_a, _b) cf_atomic64_add(_a, _b)
#define cf_atomic_int_sub(_a, _b) cf_atomic64_sub(_a, _b)
#define cf_atomic_int_incr(_a) cf_atomic64_add((_a), 1)
#define cf_atomic_int_decr(_a) cf_atomic64_add((_a), -1)
#define cf_atomic_int_cas(_a, _b, _x) cf_atomic64_cas(_a, _b, _x)
#define cf_atomic_int_cas_m(_a, _b, _x) cf_atomic64_cas_m(_a, _b, _x)
#define cf_atomic_int_fas(_a, _b) cf_atomic64_fas(_a, _b)
#define cf_atomic_int_fas_m(_a, _b) cf_atomic64_fas_m(_a, _b)
#define cf_atomic_int_addunless(_a, _b, _x) cf_atomic64_addunless(_a, _b, _x)
#define cf_atomic_int_setmax(_a, _x) cf_atomic64_setmax(_a, _x)
#endif
/* Memory barriers */
// Knowledge taken from Linux's atomic_ops.h:
#define smb_mb() asm volatile("mfence":::"memory")
/* CF_BARRIER
* All preceding memory accesses must commit before any following accesses */
#define CF_MEMORY_BARRIER() __asm__ __volatile__ ("lock; addl $0,0(%%esp)" : : : "memory")
/* CF_BARRIER_READ
* All preceding memory accesses must commit before any following accesses */
#define CF_MEMORY_BARRIER_READ() CF_MEMORY_BARRIER()
/* CF_BARRIER_WRITE
* All preceding memory accesses must commit before any following accesses */
#define CF_MEMORY_BARRIER_WRITE() __asm__ __volatile__ ("" : : : "memory")