Function pthread_mutex_unlock_impl

src/bthread/mutex.cpp:928–968

template <typename Mutex>
BUTIL_FORCE_INLINE int pthread_mutex_unlock_impl(Mutex* mutex) {
    // Don't change behavior of unlock when profiler is off.
    if (!g_cp || tls_inside_lock) {
        // This branch brings an issue that an entry created by
        // add_pthread_contention_site may not be cleared. Thus we add a
        // 16-bit rolling version in the entry to find out such entry.
        return pthread_mutex_unlock_internal(mutex);
    }
    int64_t unlock_start_ns = 0;
    bool miss_in_tls = true;
    bthread_contention_site_t saved_csite = {0,0};
#ifndef DONT_SPEEDUP_PTHREAD_CONTENTION_PROFILER_WITH_TLS
    TLSPthreadContentionSites& fast_alt = tls_csites;
    for (int i = fast_alt.count - 1; i >= 0; --i) {
        if (fast_alt.list[i].mutex == mutex) {
            if (is_contention_site_valid(fast_alt.list[i].csite)) {
                saved_csite = fast_alt.list[i].csite;
                unlock_start_ns = butil::cpuwide_time_ns();
            }
            fast_alt.list[i] = fast_alt.list[--fast_alt.count];
            miss_in_tls = false;
            break;
        }
    }
#endif
    // Check the map to see if the lock is sampled. Notice that we're still
    // inside critical section.
    if (miss_in_tls) {
        if (remove_pthread_contention_site(mutex, &saved_csite)) {
            unlock_start_ns = butil::cpuwide_time_ns();
        }
    }
    const int rc = pthread_mutex_unlock_internal(mutex);
    // [Outside lock]
    if (unlock_start_ns) {
        const int64_t unlock_end_ns = butil::cpuwide_time_ns();
        saved_csite.duration_ns += unlock_end_ns - unlock_start_ns;
        submit_contention(saved_csite, unlock_end_ns);
    }
    return rc;
}

}