pthread: Avoid crashes/odd behavior caused by spurious wakeups

This is similar to 5152196b2b47d446d9a509b9bfb318daa26a1f2b.

Derek Buitenhuis committed 13 years ago

Commit 3511d4f1 parent 157dc0b1 file · +8 −2Browse files

Showing the changes to libavfilter/pthread.c (1 of 1 file). Show all

Unified · Split

     pthread_cond_t current_job_cond;
     pthread_mutex_t current_job_lock;
     int current_job;
+    unsigned int current_execute;
     int done;
 } ThreadContext;
     ThreadContext *c = v;
     int our_job      = c->nb_jobs;
     int nb_threads   = c->nb_threads;
+    unsigned int last_execute = 0;
     int self_id;
     pthread_mutex_lock(&c->current_job_lock);
             if (c->current_job == nb_threads + c->nb_jobs)
                 pthread_cond_signal(&c->last_job_cond);
-            if (!c->done)
+            while (last_execute == c->current_execute && !c->done)
                 pthread_cond_wait(&c->current_job_cond, &c->current_job_lock);
+            last_execute = c->current_execute;
             our_job = self_id;
             if (c->done) {
 static void slice_thread_park_workers(ThreadContext *c)
 {
-    pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
+    while (c->current_job != c->nb_threads + c->nb_jobs)
+        pthread_cond_wait(&c->last_job_cond, &c->current_job_lock);
     pthread_mutex_unlock(&c->current_job_lock);
 }
         c->rets    = &dummy_ret;
         c->nb_rets = 1;
     }
+    c->current_execute++;
     pthread_cond_broadcast(&c->current_job_cond);
     slice_thread_park_workers(c);

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