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-rw-r--r--lib/thread.c57
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);