Refactor GC implications of thread sleep

* libguile/async.c (struct scm_thread_wake_data): Move definition here.
  (scm_i_setup_sleep): Remove "sleep_object".  Caller now responsible
  for scm_remember_upto_here_1 as appropriate.
  (scm_system_async_mark_for_thread): Remove scm_remember_upto_here_1
  call.
* libguile/async.h (scm_i_setup_sleep): Adapt prototype.
* libguile/threads.h (struct scm_thread_wake_data): Remove definition.
* libguile/threads.c (block_self): Remove sleep_object argument.
  (scm_join_thread_timed, scm_timed_lock_mutex)
  (scm_timed_wait_condition_variable, scm_std_select): Adapt.

4 files changed, 16 insertions, 22 deletions

diff --git a/libguile/async.c b/libguile/async.c
index b4a2c2ad2..174a87afb 100644
--- a/libguile/async.c
+++ b/libguile/async.c
@@ -75,15 +75,19 @@ scm_async_tick (void)
     }
 }
 
+struct scm_thread_wake_data {
+  scm_i_pthread_mutex_t *mutex;
+  int fd;
+};
+
 int
 scm_i_setup_sleep (scm_i_thread *t,
-		   SCM sleep_object, scm_i_pthread_mutex_t *sleep_mutex,
+		   scm_i_pthread_mutex_t *sleep_mutex,
 		   int sleep_fd)
 {
   struct scm_thread_wake_data *wake;
 
   wake = scm_gc_typed_calloc (struct scm_thread_wake_data);
-  wake->object = sleep_object;
   wake->mutex = sleep_mutex;
   wake->fd = sleep_fd;
 
@@ -148,10 +152,6 @@ SCM_DEFINE (scm_system_async_mark_for_thread, "system-async-mark", 1, 1, 0,
       scm_i_pthread_cond_signal (&t->sleep_cond);
       scm_i_pthread_mutex_unlock (wake->mutex);
 
-      /* This is needed to protect wake->mutex.
-       */
-      scm_remember_upto_here_1 (wake->object);
-
       if (wake->fd >= 0)
         {
           char dummy = 0;
diff --git a/libguile/async.h b/libguile/async.h
index 2a57236ca..343cc2ae6 100644
--- a/libguile/async.h
+++ b/libguile/async.h
@@ -35,7 +35,7 @@ SCM_API void scm_switch (void);
 SCM_API SCM scm_system_async_mark (SCM a);
 SCM_API SCM scm_system_async_mark_for_thread (SCM a, SCM thread);
 SCM_INTERNAL int scm_i_setup_sleep (scm_i_thread *,
-				    SCM obj, scm_i_pthread_mutex_t *m,
+				    scm_i_pthread_mutex_t *m,
 				    int fd);
 SCM_INTERNAL void scm_i_reset_sleep (scm_i_thread *);
 SCM_API SCM scm_noop (SCM args);
diff --git a/libguile/threads.c b/libguile/threads.c
index 863c84f71..211e57ee2 100644
--- a/libguile/threads.c
+++ b/libguile/threads.c
@@ -290,9 +290,6 @@ thread_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
    The caller of block_self must hold MUTEX.  It will be atomically
    unlocked while sleeping, just as with scm_i_pthread_cond_wait.
 
-   SLEEP_OBJECT is an arbitrary SCM value that is kept alive as long
-   as MUTEX is needed.
-
    When WAITTIME is not NULL, the sleep will be aborted at that time.
 
    The return value of block_self is an errno value.  It will be zero
@@ -304,14 +301,14 @@ thread_print (SCM exp, SCM port, scm_print_state *pstate SCM_UNUSED)
    The system asyncs themselves are not executed by block_self.
 */
 static int
-block_self (SCM queue, SCM sleep_object, scm_i_pthread_mutex_t *mutex,
+block_self (SCM queue, scm_i_pthread_mutex_t *mutex,
 	    const scm_t_timespec *waittime)
 {
   scm_i_thread *t = SCM_I_CURRENT_THREAD;
   SCM q_handle;
   int err;
 
-  if (scm_i_setup_sleep (t, sleep_object, mutex, -1))
+  if (scm_i_setup_sleep (t, mutex, -1))
     {
       scm_i_reset_sleep (t);
       err = EINTR;
@@ -988,8 +985,9 @@ SCM_DEFINE (scm_join_thread_timed, "join-thread", 1, 2, 0,
     {
       while (1)
 	{
-	  int err = block_self (t->join_queue, thread, &t->admin_mutex,
+	  int err = block_self (t->join_queue, &t->admin_mutex,
 				timeout_ptr);
+          scm_remember_upto_here_1 (thread);
 	  if (err == 0)
 	    {
 	      if (t->exited)
@@ -1200,7 +1198,8 @@ SCM_DEFINE (scm_timed_lock_mutex, "lock-mutex", 1, 1, 0,
                   return SCM_BOOL_F;
 		}
 	    }
-	  block_self (m->waiting, mutex, &m->lock, waittime);
+          block_self (m->waiting, &m->lock, waittime);
+          scm_remember_upto_here_1 (mutex);
 	  scm_i_pthread_mutex_unlock (&m->lock);
 	  SCM_TICK;
 	  scm_i_scm_pthread_mutex_lock (&m->lock);
@@ -1425,7 +1424,7 @@ SCM_DEFINE (scm_timed_wait_condition_variable, "wait-condition-variable", 2, 1,
 
       t->block_asyncs++;
 
-      err = block_self (c->waiting, cond, &m->lock, waittime);
+      err = block_self (c->waiting, &m->lock, waittime);
       scm_i_pthread_mutex_unlock (&m->lock);
 
       if (err == 0)
@@ -1543,7 +1542,7 @@ scm_std_select (int nfds,
       readfds = &my_readfds;
     }
 
-  while (scm_i_setup_sleep (t, SCM_BOOL_F, NULL, t->sleep_pipe[1]))
+  while (scm_i_setup_sleep (t, NULL, t->sleep_pipe[1]))
     {
       scm_i_reset_sleep (t);
       SCM_TICK;
diff --git a/libguile/threads.h b/libguile/threads.h
index ce8148f4e..db52f16b7 100644
--- a/libguile/threads.h
+++ b/libguile/threads.h
@@ -47,12 +47,7 @@ SCM_API scm_t_bits scm_tc16_thread;
 SCM_API scm_t_bits scm_tc16_mutex;
 SCM_API scm_t_bits scm_tc16_condvar;
 
-struct scm_thread_wake_data
-{
-  SCM object;
-  scm_i_pthread_mutex_t *mutex;
-  int fd;
-};
+struct scm_thread_wake_data;
 
 typedef struct scm_i_thread {
   struct scm_i_thread *next_thread;