Method acquire

benchmarks/tbb/queuing_mutex.cpp:32–59

A method to acquire queuing_mutex lock

//! A method to acquire queuing_mutex lock
void queuing_mutex::scoped_lock::acquire( queuing_mutex& m )
{
    __TBB_ASSERT( !this->mutex, "scoped_lock is already holding a mutex");

    // Must set all fields before the fetch_and_store, because once the
    // fetch_and_store executes, *this becomes accessible to other threads.
    mutex = &m;
    next  = NULL;
    going = 0;

    // The fetch_and_store must have release semantics, because we are
    // "sending" the fields initialized above to other processors.
    scoped_lock* pred = m.q_tail.fetch_and_store<tbb::release>(this);
    if( pred ) {
        ITT_NOTIFY(sync_prepare, mutex);
#if TBB_USE_ASSERT
        __TBB_control_consistency_helper(); // on "m.q_tail"
        __TBB_ASSERT( !pred->next, "the predecessor has another successor!");
#endif
        pred->next = this;
        spin_wait_while_eq( going, 0ul );
    }
    ITT_NOTIFY(sync_acquired, mutex);

    // Force acquire so that user's critical section receives correct values
    // from processor that was previously in the user's critical section.
    __TBB_load_with_acquire(going);
}

//! A method to acquire queuing_mutex if it is free
bool queuing_mutex::scoped_lock::try_acquire( queuing_mutex& m )