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/*-
* Copyright (c) 2014-2019 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
/*
* Publish a value to a shared location. All previous stores must complete before the value is made
* public.
*/
#define WT_PUBLISH(v, val) \
do { \
WT_WRITE_BARRIER(); \
(v) = (val); \
} while (0)
/* Write after all previous stores are completed. */
#define WT_ORDERED_WRITE(v, val) \
do { \
WT_WRITE_BARRIER(); \
(v) = (val); \
} while (0)
/*
* Read a shared location and guarantee that subsequent reads do not see any earlier state.
*/
#define WT_ORDERED_READ(v, val) \
do { \
(v) = (val); \
WT_READ_BARRIER(); \
} while (0)
/*
* Atomic versions of the flag set/clear macros.
*/
#define F_ISSET_ATOMIC(p, mask) ((p)->flags_atomic & (uint8_t)(mask))
#define F_SET_ATOMIC(p, mask) \
do { \
uint8_t __orig; \
do { \
__orig = (p)->flags_atomic; \
} while (!__wt_atomic_cas8(&(p)->flags_atomic, __orig, __orig | (uint8_t)(mask))); \
} while (0)
#define F_CLR_ATOMIC(p, mask) \
do { \
uint8_t __orig; \
do { \
__orig = (p)->flags_atomic; \
} while (!__wt_atomic_cas8(&(p)->flags_atomic, __orig, __orig & ~(uint8_t)(mask))); \
} while (0)
/*
* Cache line alignment.
*/
#if defined(__PPC64__) || defined(PPC64)
#define WT_CACHE_LINE_ALIGNMENT 128
#elif defined(__s390x__)
#define WT_CACHE_LINE_ALIGNMENT 256
#else
#define WT_CACHE_LINE_ALIGNMENT 64
#endif
/*
* Pad a structure so an array of structures get separate cache lines.
*
* Note that we avoid compiler structure alignment because that requires
* allocating aligned blocks of memory, and alignment pollutes any other type
* that contains an aligned field. It is possible that a hot field positioned
* before this one will be on the same cache line, but not if it is also
* padded.
*
* This alignment has a small impact on portability as well, as we are using an
* anonymous union here which is supported under C11, earlier versions of
* the GNU standard, and MSVC versions as early as 2003.
*/
#define WT_CACHE_LINE_PAD_BEGIN \
union { \
struct {
#define WT_CACHE_LINE_PAD_END \
} \
; \
char __padding[WT_CACHE_LINE_ALIGNMENT]; \
} \
;
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