Merge remote-tracking branch 'remotes/philmd-gitlab/tags/fw_cfg-20200704' into staging

[mirror_qemu.git] / iothread.c

diff --git a/iothread.c b/iothread.c
index 9abdbace6624d6eac24f020186cc5acffbf93277..cb082b9b26246290ded0bc075c3d933d1d3b1f4a 100644 (file)
--- a/iothread.c
+++ b/iothread.c
@@ -53,12 +53,25 @@ static void *iothread_run(void *opaque)
     IOThread *iothread = opaque;
 
     rcu_register_thread();
-
+    /*
+     * g_main_context_push_thread_default() must be called before anything
+     * in this new thread uses glib.
+     */
+    g_main_context_push_thread_default(iothread->worker_context);
     my_iothread = iothread;
     iothread->thread_id = qemu_get_thread_id();
     qemu_sem_post(&iothread->init_done_sem);
 
     while (iothread->running) {
+        /*
+         * Note: from functional-wise the g_main_loop_run() below can
+         * already cover the aio_poll() events, but we can't run the
+         * main loop unconditionally because explicit aio_poll() here
+         * is faster than g_main_loop_run() when we do not need the
+         * gcontext at all (e.g., pure block layer iothreads).  In
+         * other words, when we want to run the gcontext with the
+         * iothread we need to pay some performance for functionality.
+         */
         aio_poll(iothread->ctx, true);
 
         /*
@@ -66,12 +79,11 @@ static void *iothread_run(void *opaque)
          * changed in previous aio_poll()
          */
         if (iothread->running && atomic_read(&iothread->run_gcontext)) {
-            g_main_context_push_thread_default(iothread->worker_context);
             g_main_loop_run(iothread->main_loop);
-            g_main_context_pop_thread_default(iothread->worker_context);
         }
     }
 
+    g_main_context_pop_thread_default(iothread->worker_context);
     rcu_unregister_thread();
     return NULL;
 }
@@ -264,15 +276,15 @@ static void iothread_class_init(ObjectClass *klass, void *class_data)
     object_class_property_add(klass, "poll-max-ns", "int",
                               iothread_get_poll_param,
                               iothread_set_poll_param,
-                              NULL, &poll_max_ns_info, &error_abort);
+                              NULL, &poll_max_ns_info);
     object_class_property_add(klass, "poll-grow", "int",
                               iothread_get_poll_param,
                               iothread_set_poll_param,
-                              NULL, &poll_grow_info, &error_abort);
+                              NULL, &poll_grow_info);
     object_class_property_add(klass, "poll-shrink", "int",
                               iothread_get_poll_param,
                               iothread_set_poll_param,
-                              NULL, &poll_shrink_info, &error_abort);
+                              NULL, &poll_shrink_info);
 }
 
 static const TypeInfo iothread_info = {