Function fastlock_lock

src/fastlock.cpp:345–396

#ifndef ASM_SPINLOCK
extern "C" void fastlock_lock(struct fastlock *lock, spin_worker worker)
{
    int pidOwner;
    __atomic_load(&lock->m_pidOwner, &pidOwner, __ATOMIC_ACQUIRE);
    if (pidOwner == gettid())
    {
        ++lock->m_depth;
        return;
    }

    int tid = gettid();
    unsigned myticket = __atomic_fetch_add(&lock->m_ticket.m_avail, 1, __ATOMIC_RELEASE);
    unsigned cloops = 0;
    ticket ticketT;
    int fHighPressure;
    __atomic_load(&g_fHighCpuPressure, &fHighPressure, __ATOMIC_RELAXED);
    unsigned loopLimit = fHighPressure ? 0x10000 : 0x100000;

    if (worker != nullptr) {
        for (;;) {
            __atomic_load(&lock->m_ticket.u, &ticketT.u, __ATOMIC_ACQUIRE);
            if ((ticketT.u & 0xffff) == myticket)
                break;
            if (!worker())
                goto LNormalLoop;
        }
    } else {
LNormalLoop:
        for (;;)
        {
            __atomic_load(&lock->m_ticket.u, &ticketT.u, __ATOMIC_ACQUIRE);
            if ((ticketT.u & 0xffff) == myticket)
                break;

#if defined(__i386__) || defined(__amd64__)
            __asm__ __volatile__ ("pause");
#elif defined(__aarch64__)
            __asm__ __volatile__ ("yield");
#endif

            if ((++cloops % loopLimit) == 0)
            {
                fastlock_sleep(lock, tid, ticketT.u, myticket);
            }
        }
    }

    lock->m_depth = 1;
    __atomic_store(&lock->m_pidOwner, &tid, __ATOMIC_RELEASE);
    ANNOTATE_RWLOCK_ACQUIRED(lock, true);
    std::atomic_thread_fence(std::memory_order_acquire);
}

extern "C" int fastlock_trylock(struct fastlock *lock, int fWeak)
{