Function bthread_mutex_unlock

src/bthread/mutex.cpp:1254–1279

}

int bthread_mutex_unlock(bthread_mutex_t* m) {
    auto whole = (butil::atomic<unsigned>*)m->butex;
    bthread_contention_site_t saved_csite = {0, 0};
    bool is_valid = bthread::is_contention_site_valid(m->csite);
    if (is_valid) {
        saved_csite = m->csite;
        bthread::make_contention_site_invalid(&m->csite);
    }
    MUTEX_RESET_OWNER_COMMON(m->owner);
    const unsigned prev = whole->exchange(0, butil::memory_order_release);
    // CAUTION: the mutex may be destroyed, check comments before butex_create
    if (prev == BTHREAD_MUTEX_LOCKED) {
        return 0;
    }
    // Wakeup one waiter
    if (!is_valid) {
        bthread::butex_wake(whole);
        return 0;
    }
    const int64_t unlock_start_ns = butil::cpuwide_time_ns();
    bthread::butex_wake(whole);
    const int64_t unlock_end_ns = butil::cpuwide_time_ns();
    saved_csite.duration_ns += unlock_end_ns - unlock_start_ns;
    bthread::submit_contention(saved_csite, unlock_end_ns);
    return 0;
}

int bthread_mutexattr_init(bthread_mutexattr_t* attr) {
    attr->enable_csite = true;