commit b60ec76a13b0d2cd06b4a681f025c180f4dd79a1
author Peter Xu <peterx@redhat.com> Wed Mar 06 19:55:31 2019 +0800
committer Stefan Hajnoczi <stefanha@redhat.com> Fri Mar 08 10:20:23 2019 +0000
tree b33cdec75d751f9ed39a739519aa0365f64ab171
parent 0bd2d233c628dcfcd2b24b7b7f59e8fcd2dcbae3

iothread: push gcontext earlier in the thread_fn

We were pushing the context until right before running the gmainloop.
Now since we have everything unconditionally, we can move this
earlier.

One benefit is that now it's done even before init_done_sem, so as
long as the iothread user calls iothread_create() and completes, we
know that the thread stack is ready.

Signed-off-by: Peter Xu <peterx@redhat.com>
Message-id: 20190306115532.23025-5-peterx@redhat.com
Message-Id: <20190306115532.23025-5-peterx@redhat.com>

[Tweaked comment wording as discussed with Peter Xu.
--Stefan]

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

iothread.c

diff --git a/iothread.c b/iothread.c
index 9abdbac..ad64c75 100644
--- a/iothread.c
+++ b/iothread.c
@@ -53,7 +53,11 @@
     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);
@@ -66,12 +70,11 @@
          * 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;
 }