[glib/wip/alexl/gtask-bt] Add some support code to GTask and a gtask-bt gdb command
- From: Alexander Larsson <alexl src gnome org>
- To: commits-list gnome org
- Cc:
- Subject: [glib/wip/alexl/gtask-bt] Add some support code to GTask and a gtask-bt gdb command
- Date: Tue, 29 Aug 2017 11:44:43 +0000 (UTC)
commit 6fb5b6d0f293a8a7ae67301c2b4f6f7187959d36
Author: Alexander Larsson <alexl redhat com>
Date: Tue Aug 29 12:54:09 2017 +0200
Add some support code to GTask and a gtask-bt gdb command
Whenever we invoke the GTask callback we push the current
task to a thread-local variable, and during construction we
pick this up as the "parent" of the task which lets us
construct call chains for GTask invocations.
Additionally, g_task_new is #defined to g_task_new_with_caller
with an additional __builtin_return_address(0) argument, which
gives the caller of the function that created the GTask, which
is typically the interesting user-level code.
We then read this back in a gtask-bt gdb command that prints a
backtrace like:
Thread 5 "gdbus" hit Breakpoint 1, g_task_new_with_caller (source_object=source_object@entry=0x1003e0130,
cancellable=cancellable@entry=0x1003bbf00,
callback=callback@entry=0x7fa8d0efa890 <_g_dbus_worker_do_read_cb>,
callback_data=callback_data@entry=0x1003e3800, caller=0x7fa8d0ef8a81 <_g_dbus_worker_do_read_unlocked+161>)
at gtask.c:743
743 {
(gdb) gtask-bt
#1 GTask 0x7fa8b4004cc0 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#2 GTask 0x7fa8b8012200 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#3 GTask 0x7fa8b80122f0 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#4 GTask 0x7fa8b80123e0 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#5 GTask 0x7fa8b80124d0 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#6 GTask 0x7fa8b8012020 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#7 GTask 0x100c5c690 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#8 GTask 0x100988030 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#9 GTask 0x1009886c0 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#10 GTask 0x1009883f0 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#11 GTask 0x1009d1a00 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#12 GTask 0x100766930 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
#13 GTask 0x10072dae0 - _g_dbus_worker_do_read_unlocked (gdbusprivate.c:854)
_g_socket_read_with_control_messages -> _g_dbus_worker_do_read_cb
gio/gtask.c | 135 ++++++++++++++++++++++++++++++++++++++++++++++--------
gio/gtask.h | 9 ++++
glib/glib_gdb.py | 29 ++++++++++++
3 files changed, 154 insertions(+), 19 deletions(-)
---
diff --git a/gio/gtask.c b/gio/gtask.c
index 7eb0185..c18f499 100644
--- a/gio/gtask.c
+++ b/gio/gtask.c
@@ -27,6 +27,8 @@
#include "glibintl.h"
+#undef g_task_new
+
/**
* SECTION:gtask
* @short_description: Cancellable synchronous or asynchronous task
@@ -544,6 +546,11 @@ struct _GTask {
gpointer task_data;
GDestroyNotify task_data_destroy;
+ GTask *invoke_stack_parent;
+ GTask *parent;
+ guint n_children;
+ gpointer caller;
+
GMainContext *context;
gint64 creation_time;
gint priority;
@@ -601,6 +608,32 @@ static GSource *task_pool_manager;
static guint64 task_wait_time;
static gint tasks_running;
+__thread GTask *g_task_invoke_stack = NULL;
+
+static void
+g_task_push (GTask *task)
+{
+ g_assert (task->invoke_stack_parent == NULL);
+ task->invoke_stack_parent = g_task_invoke_stack;
+ g_task_invoke_stack = task;
+}
+
+static void
+g_task_pop (GTask *task)
+{
+ g_assert (g_task_invoke_stack == task);
+ g_task_invoke_stack = task->invoke_stack_parent;
+ task->invoke_stack_parent = NULL;
+}
+
+GTask * g_task_peek (void);
+
+GTask *
+g_task_peek (void)
+{
+ return g_task_invoke_stack;
+}
+
/* When the task pool fills up and blocks, and the program keeps
* queueing more tasks, we will slowly add more threads to the pool
* (in case the existing tasks are trying to queue subtasks of their
@@ -617,10 +650,51 @@ static gint tasks_running;
#define G_TASK_WAIT_TIME_MULTIPLIER 1.03
#define G_TASK_WAIT_TIME_MAX (30 * 60 * 1000000)
+static GList *all_tasks = NULL;
+G_LOCK_DEFINE_STATIC (all_tasks);
+
+static int
+g_task_depth (GTask *task)
+{
+ if (task->parent)
+ return 1 + g_task_depth (task->parent);
+ return 1;
+}
+
static void
g_task_init (GTask *task)
{
+ GTask *parent;
+
+ G_LOCK (all_tasks);
+ all_tasks = g_list_prepend (all_tasks, task);
+ G_UNLOCK (all_tasks);
+
task->check_cancellable = TRUE;
+ parent = g_task_peek ();
+ if (parent)
+ {
+ task->parent = g_object_ref (parent);
+ parent->n_children++;
+ g_print ("GTask %p created with parent %p (depth %d)\n", task, parent, g_task_depth (task));
+ }
+}
+
+gpointer * g_tasks_get (void);
+
+gpointer *
+g_tasks_get (void)
+{
+ GPtrArray *array = g_ptr_array_new ();
+ GList *l;
+
+ G_LOCK (all_tasks);
+ for (l = all_tasks; l != NULL; l = l->next)
+ g_ptr_array_add (array, l->data);
+ g_ptr_array_add (array, NULL);
+ G_UNLOCK (all_tasks);
+
+ return g_ptr_array_free (array, FALSE);
}
static void
@@ -628,6 +702,16 @@ g_task_finalize (GObject *object)
{
GTask *task = G_TASK (object);
+ G_LOCK (all_tasks);
+ all_tasks = g_list_remove (all_tasks, task);
+ G_UNLOCK (all_tasks);
+ if (task->parent)
+ {
+ g_print ("GTask %p freed with parent %p\n", task, task->parent);
+ task->parent->n_children--;
+ g_clear_object (&task->parent);
+ }
+
g_clear_object (&task->source_object);
g_clear_object (&task->cancellable);
@@ -652,6 +736,35 @@ g_task_finalize (GObject *object)
G_OBJECT_CLASS (g_task_parent_class)->finalize (object);
}
+GTask *
+g_task_new_with_caller (gpointer source_object,
+ GCancellable *cancellable,
+ GAsyncReadyCallback callback,
+ gpointer callback_data,
+ gpointer caller)
+{
+ GTask *task;
+ GSource *source;
+
+ task = g_object_new (G_TYPE_TASK, NULL);
+ task->source_object = source_object ? g_object_ref (source_object) : NULL;
+ task->cancellable = cancellable ? g_object_ref (cancellable) : NULL;
+ task->caller = caller;
+ task->callback = callback;
+ task->callback_data = callback_data;
+ task->context = g_main_context_ref_thread_default ();
+
+ source = g_main_current_source ();
+ if (source)
+ task->creation_time = g_source_get_time (source);
+
+ TRACE (GIO_TASK_NEW (task, source_object, cancellable,
+ callback, callback_data));
+
+ return task;
+}
+
+
/**
* g_task_new:
* @source_object: (nullable) (type GObject): the #GObject that owns
@@ -687,24 +800,7 @@ g_task_new (gpointer source_object,
GAsyncReadyCallback callback,
gpointer callback_data)
{
- GTask *task;
- GSource *source;
-
- task = g_object_new (G_TYPE_TASK, NULL);
- task->source_object = source_object ? g_object_ref (source_object) : NULL;
- task->cancellable = cancellable ? g_object_ref (cancellable) : NULL;
- task->callback = callback;
- task->callback_data = callback_data;
- task->context = g_main_context_ref_thread_default ();
-
- source = g_main_current_source ();
- if (source)
- task->creation_time = g_source_get_time (source);
-
- TRACE (GIO_TASK_NEW (task, source_object, cancellable,
- callback, callback_data));
-
- return task;
+ return g_task_new_with_caller (source_object, cancellable, callback, callback_data, NULL);
}
/**
@@ -1131,7 +1227,6 @@ g_task_get_source_tag (GTask *task)
return task->source_tag;
}
-
static void
g_task_return_now (GTask *task)
{
@@ -1139,6 +1234,7 @@ g_task_return_now (GTask *task)
task->callback_data));
g_main_context_push_thread_default (task->context);
+ g_task_push (task);
if (task->callback != NULL)
{
@@ -1150,6 +1246,7 @@ g_task_return_now (GTask *task)
task->completed = TRUE;
g_object_notify (G_OBJECT (task), "completed");
+ g_task_pop (task);
g_main_context_pop_thread_default (task->context);
}
diff --git a/gio/gtask.h b/gio/gtask.h
index 92cd2b1..25d6241 100644
--- a/gio/gtask.h
+++ b/gio/gtask.h
@@ -44,6 +44,12 @@ GTask *g_task_new (gpointer source_object,
GCancellable *cancellable,
GAsyncReadyCallback callback,
gpointer callback_data);
+GLIB_AVAILABLE_IN_2_54
+GTask *g_task_new_with_caller (gpointer source_object,
+ GCancellable *cancellable,
+ GAsyncReadyCallback callback,
+ gpointer callback_data,
+ gpointer caller);
GLIB_AVAILABLE_IN_2_36
void g_task_report_error (gpointer source_object,
@@ -155,6 +161,9 @@ gboolean g_task_had_error (GTask *task);
GLIB_AVAILABLE_IN_2_44
gboolean g_task_get_completed (GTask *task);
+
+#define g_task_new(_o,_c,_cb,_cbd) g_task_new_with_caller(_o,_c,_cb,_cbd,__builtin_return_address(0))
+
G_END_DECLS
#endif /* __G_TASK_H__ */
diff --git a/glib/glib_gdb.py b/glib/glib_gdb.py
index 38f101a..0a56eff 100644
--- a/glib/glib_gdb.py
+++ b/glib/glib_gdb.py
@@ -259,3 +259,32 @@ class ForeachCommand (gdb.Command):
func(var, container, command)
ForeachCommand ()
+
+
+class GTaskBacktrace (gdb.Command):
+ """GTask backtrace"""
+ def __init__ (self):
+ super (GTaskBacktrace, self).__init__ ("gtask-bt", gdb.COMMAND_STACK)
+ def decode_pc_function(self, value):
+ block = gdb.block_for_pc(int(value))
+ return block.function.name
+ def decode_pc(self, value):
+ f = self.decode_pc_function(value)
+ sal = gdb.find_pc_line(int(value))
+ return "%s (%s:%d)" % (f, sal.symtab.filename, sal.line)
+ def print_task_frame(self, frame, task):
+ print ("#%d GTask %s - %s\n %s -> %s" % (
+ frame,
+ hex(int(task)),
+ self.decode_pc(task["caller"]),
+ self.decode_pc_function(task["source_tag"]),
+ self.decode_pc_function(task["callback"])))
+ def invoke (self, arg, from_tty):
+ task = gdb.lookup_global_symbol("g_task_invoke_stack").value()
+ frame = 1
+ while int(task) != 0:
+ self.print_task_frame(frame, task)
+ task = task["parent"]
+ frame = frame + 1
+
+GTaskBacktrace()
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