Revert "gmain: only signal GWakeup right before or during a blocking poll"

This reverts commit 9ba95e25b7.

It is causing undiagnosed problems with WebKit and other users of GLib.
See https://bugzilla.gnome.org/show_bug.cgi?id=761102#c44 and
https://bugzilla.gnome.org/show_bug.cgi?id=761102#c46.

Reverting it until someone works out what the problem is.

https://bugzilla.gnome.org/show_bug.cgi?id=761102
This commit is contained in:
Philip Withnall 2018-01-03 11:25:52 +00:00
parent e9757096c2
commit 4976e81090

View File

@ -277,8 +277,7 @@ struct _GMainContext
guint next_id; guint next_id;
GList *source_lists; GList *source_lists;
gboolean in_check_or_prepare; gint in_check_or_prepare;
gboolean need_wakeup;
GPollRec *poll_records; GPollRec *poll_records;
guint n_poll_records; guint n_poll_records;
@ -652,7 +651,6 @@ g_main_context_new (void)
context->pending_dispatches = g_ptr_array_new (); context->pending_dispatches = g_ptr_array_new ();
context->need_wakeup = FALSE;
context->time_is_fresh = FALSE; context->time_is_fresh = FALSE;
context->wakeup = g_wakeup_new (); context->wakeup = g_wakeup_new ();
@ -1129,11 +1127,17 @@ source_remove_from_context (GSource *source,
static void static void
conditional_wakeup (GMainContext *context) conditional_wakeup (GMainContext *context)
{ {
/* This flag is set if at the start of prepare() we have no other ready /* We want to signal wakeups in two cases:
* sources, and hence would wait in poll(). In that case, any other threads * 1 When the context is owned by another thread
* attaching sources will need to signal a wakeup. * 2 When the context owner is NULL (two subcases)
* 2a Possible if the context has never been acquired
* 2b Or if the context has no current owner
*
* At least case 2a) is necessary to ensure backwards compatibility with
* qemu's use of GMainContext.
* https://bugzilla.gnome.org/show_bug.cgi?id=761102#c14
*/ */
if (context->need_wakeup) if (context->owner != G_THREAD_SELF)
g_wakeup_signal (context->wakeup); g_wakeup_signal (context->wakeup);
} }
@ -3383,10 +3387,6 @@ g_main_context_prepare (GMainContext *context,
LOCK_CONTEXT (context); LOCK_CONTEXT (context);
/* context->need_wakeup is protected by LOCK_CONTEXT/UNLOCK_CONTEXT,
* so need not set it yet.
*/
context->time_is_fresh = FALSE; context->time_is_fresh = FALSE;
if (context->in_check_or_prepare) if (context->in_check_or_prepare)
@ -3512,8 +3512,6 @@ g_main_context_prepare (GMainContext *context,
} }
} }
g_source_iter_clear (&iter); g_source_iter_clear (&iter);
/* See conditional_wakeup() where this is used */
context->need_wakeup = (n_ready == 0);
TRACE (GLIB_MAIN_CONTEXT_AFTER_PREPARE (context, current_priority, n_ready)); TRACE (GLIB_MAIN_CONTEXT_AFTER_PREPARE (context, current_priority, n_ready));
@ -3648,12 +3646,6 @@ g_main_context_check (GMainContext *context,
TRACE (GLIB_MAIN_CONTEXT_BEFORE_CHECK (context, max_priority, fds, n_fds)); TRACE (GLIB_MAIN_CONTEXT_BEFORE_CHECK (context, max_priority, fds, n_fds));
/* We don't need to wakeup during check or dispatch, because
* all sources will be re-evaluated during prepare/query.
*/
context->need_wakeup = FALSE;
/* And if we have a wakeup pending, acknowledge it */
for (i = 0; i < n_fds; i++) for (i = 0; i < n_fds; i++)
{ {
if (fds[i].fd == context->wake_up_rec.fd) if (fds[i].fd == context->wake_up_rec.fd)