Function bthread_mutex_lock_impl

src/bthread/mutex.cpp:1213–1243

}

static int bthread_mutex_lock_impl(bthread_mutex_t* __restrict m,
                                   const struct timespec* __restrict abstime) {
    if (0 == bthread::mutex_trylock_impl(m)) {
        return 0;
    }
    // Don't sample when contention profiler is off.
    if (!bthread::g_cp) {
        return bthread::mutex_lock_contended_impl(m, abstime);
    }
    // Ask Collector if this (contended) locking should be sampled.
    const size_t sampling_range =
        m->enable_csite ? bvar::is_collectable(&bthread::g_cp_sl) : bvar::INVALID_SAMPLING_RANGE;
    if (!bvar::is_sampling_range_valid(sampling_range)) { // Don't sample
        return bthread::mutex_lock_contended_impl(m, abstime);
    }
    // Start sampling.
    const int64_t start_ns = butil::cpuwide_time_ns();
    // NOTE: Don't modify m->csite outside lock since multiple threads are
    // still contending with each other.
    const int rc = bthread::mutex_lock_contended_impl(m, abstime);
    if (!rc) { // Inside lock
        m->csite.duration_ns = butil::cpuwide_time_ns() - start_ns;
        m->csite.sampling_range = sampling_range;
    } else if (rc == ETIMEDOUT) {
        // Failed to lock due to ETIMEDOUT, submit the elapse directly.
        const int64_t end_ns = butil::cpuwide_time_ns();
        const bthread_contention_site_t csite = {end_ns - start_ns, sampling_range};
        bthread::submit_contention(csite, end_ns);
    }
    return rc;
}

int bthread_mutex_lock(bthread_mutex_t* m) {
    return bthread_mutex_lock_impl(m, NULL);