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Only use acq ordering for MicroSpinLock locking #2532

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Only use acq ordering for MicroSpinLock locking #2532

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8 changes: 4 additions & 4 deletions folly/synchronization/MicroSpinLock.h
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Original file line number Diff line number Diff line change
Expand Up @@ -68,15 +68,15 @@ struct MicroSpinLock {
void init() noexcept { payload()->store(FREE); }

bool try_lock() noexcept {
bool ret = xchg(LOCKED) == FREE;
bool ret = xchg_acq(LOCKED) == FREE;
annotate_rwlock_try_acquired(
this, annotate_rwlock_level::wrlock, ret, __FILE__, __LINE__);
return ret;
}

void lock() noexcept {
detail::Sleeper sleeper;
while (xchg(LOCKED) != FREE) {
while (xchg_acq(LOCKED) != FREE) {
do {
sleeper.wait();
} while (payload()->load(std::memory_order_relaxed) == LOCKED);
Expand All @@ -98,9 +98,9 @@ struct MicroSpinLock {
return reinterpret_cast<std::atomic<uint8_t>*>(&this->lock_);
}

uint8_t xchg(uint8_t newVal) noexcept {
uint8_t xchg_acq(uint8_t newVal) noexcept {
return std::atomic_exchange_explicit(
payload(), newVal, std::memory_order_acq_rel);
payload(), newVal, std::memory_order_acquire);
}
};
static_assert(
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