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use condvar and exception-proof mutex for chain swaps in graph

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git-svn-id: svn://localhost/ardour2/branches/3.0@7299 d708f5d6-7413-0410-9779-e7cbd77b26cf
This commit is contained in:
Paul Davis 2010-06-24 18:04:02 +00:00
parent 59a3dd2383
commit e72d710734
2 changed files with 11 additions and 19 deletions
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3
libs/ardour/ardour/graph.h
View File

@ -109,7 +109,8 @@ class Graph : public SessionHandleRef
bool _graph_empty;
// chain swapping
pthread_mutex_t _swap_mutex;
Glib::Mutex _swap_mutex;
Glib::Cond _cleanup_cond;
volatile int _current_chain;
volatile int _pending_chain;
volatile int _setup_chain;

27
libs/ardour/graph.cc
View File

@ -17,7 +17,6 @@
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <iostream>
#include <stdio.h>
#include <cmath>
@ -53,7 +52,6 @@ Graph::Graph (Session & session)
_execution_tokens = 0;
pthread_mutex_init (&_swap_mutex, NULL);
_current_chain = 0;
_pending_chain = 0;
_setup_chain = 1;
@ -118,8 +116,9 @@ Graph::session_going_away()
void
Graph::clear_other_chain ()
{
Glib::Mutex::Lock ls (_swap_mutex);
while (1) {
pthread_mutex_lock (&_swap_mutex);
if (_setup_chain != _pending_chain) {
for (node_list_t::iterator ni=_nodes_rt[_setup_chain].begin(); ni!=_nodes_rt[_setup_chain].end(); ni++) {
@ -128,17 +127,12 @@ Graph::clear_other_chain ()
_nodes_rt[_setup_chain].clear ();
_init_trigger_list[_setup_chain].clear ();
pthread_mutex_unlock (&_swap_mutex);
return;
break;
}
pthread_mutex_unlock (&_swap_mutex);
/* setup chain == pending chain - we have
to wait till this is no longer true.
*/
cerr << "Wait for setup != pending (currently " << _setup_chain << '/' << _pending_chain << endl;
int ret = sem_wait (&_cleanup_sem);
cerr << " back from that wait, ret = " << ret << endl;
_cleanup_cond.wait (_swap_mutex);
}
}
@ -148,17 +142,16 @@ Graph::prep()
node_list_t::iterator i;
int chain;
if (pthread_mutex_trylock (&_swap_mutex) == 0) {
if (_swap_mutex.trylock()) {
// we got the swap mutex.
if (_current_chain != _pending_chain)
{
printf ("chain swap ! %d -> %d\n", _current_chain, _pending_chain);
// printf ("chain swap ! %d -> %d\n", _current_chain, _pending_chain);
_setup_chain = _current_chain;
_current_chain = _pending_chain;
printf ("\tNOW: setup %d current %d pending %d\n", _setup_chain, _current_chain, _pending_chain);
sem_post (&_cleanup_sem);
_cleanup_cond.signal ();
}
pthread_mutex_unlock (&_swap_mutex);
_swap_mutex.unlock ();
}
chain = _current_chain;
@ -250,8 +243,8 @@ void
Graph::rechain (boost::shared_ptr<RouteList> routelist)
{
node_list_t::iterator ni;
Glib::Mutex::Lock ls (_swap_mutex);
pthread_mutex_lock (&_swap_mutex);
int chain = _setup_chain;
DEBUG_TRACE (DEBUG::Graph, string_compose ("============== setup %1\n", chain));
// set all refcounts to 0;
@ -309,10 +302,8 @@ Graph::rechain (boost::shared_ptr<RouteList> routelist)
_pending_chain = chain;
dump(chain);
pthread_mutex_unlock (&_swap_mutex);
}
bool
Graph::run_one()
{