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mdbx: simplify safe64_reset().

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Леонид Юрьев (Leonid Yuriev) 2022-07-08 22:04:37 +03:00
parent ad5a83586b
commit baea4c81c9
1 changed files with 19 additions and 25 deletions
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44
src/core.c
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@ -1086,40 +1086,34 @@ static __always_inline uint64_t safe64_txnid_next(uint64_t txnid) {
return txnid;
}
#if defined(MDBX_HAVE_C11ATOMICS) && defined(__LCC__)
#define safe64_reset(p, single_writer) \
atomic_store64(p, UINT64_MAX, \
(single_writer) ? mo_AcquireRelease \
: mo_SequentialConsistency)
#else
/* Atomically make target value >= SAFE64_INVALID_THRESHOLD */
static __always_inline void safe64_reset(MDBX_atomic_uint64_t *p,
bool single_writer) {
#if !MDBX_64BIT_CAS
if (!single_writer) {
STATIC_ASSERT(xMDBX_TXNID_STEP > 1);
if (single_writer) {
#if MDBX_64BIT_ATOMIC && MDBX_WORDBITS >= 64
atomic_store64(p, UINT64_MAX, mo_AcquireRelease);
#else
atomic_store32(&p->high, UINT32_MAX, mo_AcquireRelease);
#endif /* MDBX_64BIT_ATOMIC && MDBX_WORDBITS >= 64 */
} else {
#if MDBX_64BIT_CAS && MDBX_64BIT_ATOMIC
/* atomically make value >= SAFE64_INVALID_THRESHOLD by 64-bit operation */
atomic_store64(p, UINT64_MAX, mo_SequentialConsistency);
#elif MDBX_64BIT_CAS
/* atomically make value >= SAFE64_INVALID_THRESHOLD by 32-bit operation */
atomic_store32(&p->high, UINT32_MAX, mo_SequentialConsistency);
#else
/* it is safe to increment low-part to avoid ABA, since xMDBX_TXNID_STEP > 1
* and overflow was preserved in safe64_txnid_next() */
STATIC_ASSERT(xMDBX_TXNID_STEP > 1);
atomic_add32(&p->low, 1) /* avoid ABA in safe64_reset_compare() */;
atomic_store32(
&p->high, UINT32_MAX,
mo_Relaxed) /* atomically make >= SAFE64_INVALID_THRESHOLD */;
atomic_store32(&p->high, UINT32_MAX, mo_SequentialConsistency);
atomic_add32(&p->low, 1) /* avoid ABA in safe64_reset_compare() */;
} else
#endif /* !MDBX_64BIT_CAS */
#if MDBX_64BIT_ATOMIC
/* atomically make value >= SAFE64_INVALID_THRESHOLD by 64-bit operation */
atomic_store64(p, UINT64_MAX,
single_writer ? mo_AcquireRelease
: mo_SequentialConsistency);
#else
/* atomically make value >= SAFE64_INVALID_THRESHOLD by 32-bit operation */
atomic_store32(&p->high, UINT32_MAX,
single_writer ? mo_AcquireRelease : mo_SequentialConsistency);
#endif /* MDBX_64BIT_ATOMIC */
#endif /* MDBX_64BIT_CAS && MDBX_64BIT_ATOMIC */
}
assert(p->weak >= SAFE64_INVALID_THRESHOLD);
mdbx_jitter4testing(true);
}
#endif /* LCC && MDBX_HAVE_C11ATOMICS */
static __always_inline bool safe64_reset_compare(MDBX_atomic_uint64_t *p,
txnid_t compare) {