| /* |
| Copyright 2005-2010 Intel Corporation. All Rights Reserved. |
| |
| This file is part of Threading Building Blocks. |
| |
| Threading Building Blocks is free software; you can redistribute it |
| and/or modify it under the terms of the GNU General Public License |
| version 2 as published by the Free Software Foundation. |
| |
| Threading Building Blocks is distributed in the hope that it will be |
| useful, but WITHOUT ANY WARRANTY; without even the implied warranty |
| of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| GNU General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with Threading Building Blocks; if not, write to the Free Software |
| Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| |
| As a special exception, you may use this file as part of a free software |
| library without restriction. Specifically, if other files instantiate |
| templates or use macros or inline functions from this file, or you compile |
| this file and link it with other files to produce an executable, this |
| file does not by itself cause the resulting executable to be covered by |
| the GNU General Public License. This exception does not however |
| invalidate any other reasons why the executable file might be covered by |
| the GNU General Public License. |
| */ |
| |
| #include "concurrent_monitor.h" |
| |
| namespace tbb { |
| namespace internal { |
| |
| void concurrent_monitor::prepare_wait( thread_context& thr, void* ctx ) { |
| // this is good place to pump previous spurious wakeup |
| if( thr.spurious ) { |
| thr.spurious = false; |
| thr.sema.P(); |
| } |
| thr.context = ctx; |
| thr.in_waitset = true; |
| { |
| tbb::spin_mutex::scoped_lock l( mutex_ec ); |
| thr.epoch = epoch; |
| waitset_ec.add( (waitset_t::node_t*)&thr ); |
| } |
| __TBB_rel_acq_fence(); |
| } |
| |
| void concurrent_monitor::cancel_wait( thread_context& thr ) { |
| // spurious wakeup will be pumped in the following prepare_wait() |
| thr.spurious = true; |
| // try to remove node from waitset |
| bool th_in_waitset = thr.in_waitset; |
| if( th_in_waitset ) { |
| tbb::spin_mutex::scoped_lock l( mutex_ec ); |
| if (thr.in_waitset) { |
| // successfully removed from waitset, |
| // so there will be no spurious wakeup |
| thr.in_waitset = false; |
| thr.spurious = false; |
| waitset_ec.remove( (waitset_t::node_t&)thr ); |
| } |
| } |
| } |
| |
| void concurrent_monitor::notify_one_relaxed() { |
| if( waitset_ec.size()==0 ) |
| return; |
| waitset_node_t* n; |
| const waitset_node_t* end = waitset_ec.end(); |
| { |
| tbb::spin_mutex::scoped_lock l( mutex_ec ); |
| epoch = epoch + 1; |
| n = waitset_ec.front(); |
| if( n!=end ) { |
| waitset_ec.remove( *n ); |
| to_thread_context(n)->in_waitset = false; |
| } |
| } |
| if( n!=end ) |
| to_thread_context(n)->sema.V(); |
| } |
| |
| void concurrent_monitor::notify_all_relaxed() { |
| if( waitset_ec.size()==0 ) |
| return; |
| dllist_t temp; |
| const waitset_node_t* end; |
| { |
| tbb::spin_mutex::scoped_lock l( mutex_ec ); |
| epoch = epoch + 1; |
| waitset_ec.flush_to( temp ); |
| end = temp.end(); |
| for( waitset_node_t* n=temp.front(); n!=end; n=n->next ) |
| to_thread_context(n)->in_waitset = false; |
| } |
| waitset_node_t* nxt; |
| for( waitset_node_t* n=temp.front(); n!=end; n=nxt ) { |
| nxt = n->next; |
| to_thread_context(n)->sema.V(); |
| } |
| #if TBB_USE_DEBUG |
| temp.clear(); |
| #endif |
| } |
| |
| } // namespace internal |
| } // namespace tbb |