1 files changed, 41 insertions, 16 deletions

diff --git a/lib/thread.c b/lib/thread.c
index af52b057..fb6fe375 100644
--- a/lib/thread.c
+++ b/lib/thread.c
@@ -903,6 +903,24 @@ thread_timer_process (struct thread_list *list, struct timeval *timenow)
   return ready;
 }
 
+/* process a list en masse, e.g. for event thread lists */
+static unsigned int
+thread_process (struct thread_list *list)
+{
+  struct thread *thread;
+  unsigned int ready = 0;
+  
+  for (thread = list->head; thread; thread = thread->next)
+    {
+      thread_list_delete (list, thread);
+      thread->type = THREAD_READY;
+      thread_list_add (&thread->master->ready, thread);
+      ready++;
+    }
+  return ready;
+}
+
+
 /* Fetch next ready thread. */
 struct thread *
 thread_fetch (struct thread_master *m, struct thread *fetch)
@@ -911,41 +929,48 @@ thread_fetch (struct thread_master *m, struct thread *fetch)
   fd_set readfd;
   fd_set writefd;
   fd_set exceptfd;
-  struct timeval timer_val;
+  struct timeval timer_val = { .tv_sec = 0, .tv_usec = 0 };
   struct timeval timer_val_bg;
-  struct timeval *timer_wait;
+  struct timeval *timer_wait = &timer_val;
   struct timeval *timer_wait_bg;
 
   while (1)
     {
       int num = 0;
       
-      /* Signals are highest priority */
+      /* Signals pre-empt everything */
       quagga_sigevent_process ();
        
-      /* Normal event are the next highest priority.  */
-      if ((thread = thread_trim_head (&m->event)) != NULL)
-        return thread_run (m, thread, fetch);
-      
-      /* If there are any ready threads from previous scheduler runs,
-       * process top of them.  
+      /* Drain the ready queue of already scheduled jobs, before scheduling
+       * more.
        */
       if ((thread = thread_trim_head (&m->ready)) != NULL)
         return thread_run (m, thread, fetch);
       
+      /* To be fair to all kinds of threads, and avoid starvation, we
+       * need to be careful to consider all thread types for scheduling
+       * in each quanta. I.e. we should not return early from here on.
+       */
+       
+      /* Normal event are the next highest priority.  */
+      thread_process (&m->event);
+      
       /* Structure copy.  */
       readfd = m->readfd;
       writefd = m->writefd;
       exceptfd = m->exceptfd;
       
       /* Calculate select wait timer if nothing else to do */
-      quagga_get_relative (NULL);
-      timer_wait = thread_timer_wait (&m->timer, &timer_val);
-      timer_wait_bg = thread_timer_wait (&m->background, &timer_val_bg);
-      
-      if (timer_wait_bg &&
-	  (!timer_wait || (timeval_cmp (*timer_wait, *timer_wait_bg) > 0)))
-	timer_wait = timer_wait_bg;
+      if (m->ready.count == 0)
+        {
+          quagga_get_relative (NULL);
+          timer_wait = thread_timer_wait (&m->timer, &timer_val);
+          timer_wait_bg = thread_timer_wait (&m->background, &timer_val_bg);
+          
+          if (timer_wait_bg &&
+              (!timer_wait || (timeval_cmp (*timer_wait, *timer_wait_bg) > 0)))
+            timer_wait = timer_wait_bg;
+        }
       
       num = select (FD_SETSIZE, &readfd, &writefd, &exceptfd, timer_wait);