bool task_group_context::cancel_group_execution () {
__TBB_ASSERT ( my_cancellation_requested == 0 || my_cancellation_requested == 1, "Invalid cancellation state");
if ( my_cancellation_requested || as_atomic(my_cancellation_requested).compare_and_swap(1, 0) ) {
// This task group and any descendants have already been canceled.
// (A newly added descendant would inherit its parent's my_cancellation_requested,
// not missing out on any cancellation still being propagated, and a context cannot be uncanceled.)
return false;
}
governor::local_scheduler_weak()->my_market->propagate_task_group_state( &task_group_context::my_cancellation_requested, *this, (uintptr_t)1 );
return true;
}
/** This method must be invoked under my_arenas_list_mutex. **/
arena* market::arena_in_need ( arena_list_type &arenas, arena *&next ) {
if ( arenas.empty() )
return NULL;
arena_list_type::iterator it = next;
__TBB_ASSERT( it != arenas.end(), NULL );
do {
arena& a = *it;
if ( ++it == arenas.end() )
it = arenas.begin();
if ( a.num_workers_active() < a.my_num_workers_allotted ) {
a.my_references += 2; // add a worker
#if __TBB_TRACK_PRIORITY_LEVEL_SATURATION
++a.my_num_workers_present;
++my_priority_levels[a.my_top_priority].workers_present;
#endif /* __TBB_TRACK_PRIORITY_LEVEL_SATURATION */
as_atomic(next) = &*it; // a subject for innocent data race under the reader lock
// TODO: rework global round robin policy to local or random to avoid this write
return &a;
}
} while ( it != next );
return NULL;
}