'event-loop-base' provides basic property handling for all 'AioContext'
based event loops. So let's define a new 'MainLoopClass' that inherits
from it. This will permit tweaking the main loop's properties through
qapi as well as through the command line using the '-object' keyword[1].
Only one instance of 'MainLoopClass' might be created at any time.
'EventLoopBaseClass' learns a new callback, 'can_be_deleted()' so as to
mark 'MainLoop' as non-deletable.
[1] For example:
-object main-loop,id=main-loop,aio-max-batch=<value>
Signed-off-by: Nicolas Saenz Julienne <nsaen...@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefa...@redhat.com>
---
Changes since v4:
- Move unrelevant qom.json code into patch #1
Changes since v3:
- Rework qom.json
Changes since v2:
- Fix mainloop's qapi versioning
Changes since v1:
- Fix json files to differentiate between iothread and main-loop
- Use OBJECT_DECLARE_TYPE()
- Fix build dependencies
event-loop-base.c | 13 ++++++++
include/qemu/main-loop.h | 10 ++++++
include/sysemu/event-loop-base.h | 1 +
meson.build | 3 +-
qapi/qom.json | 12 +++++++
util/main-loop.c | 56 ++++++++++++++++++++++++++++++++
6 files changed, 94 insertions(+), 1 deletion(-)
diff --git a/event-loop-base.c b/event-loop-base.c
index a924c73a7c..e7f99a6ec8 100644
--- a/event-loop-base.c
+++ b/event-loop-base.c
@@ -73,10 +73,23 @@ static void event_loop_base_complete(UserCreatable *uc,
Error **errp)
}
}
+static bool event_loop_base_can_be_deleted(UserCreatable *uc)
+{
+ EventLoopBaseClass *bc = EVENT_LOOP_BASE_GET_CLASS(uc);
+ EventLoopBase *backend = EVENT_LOOP_BASE(uc);
+
+ if (bc->can_be_deleted) {
+ return bc->can_be_deleted(backend);
+ }
+
+ return true;
+}
+
static void event_loop_base_class_init(ObjectClass *klass, void *class_data)
{
UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
ucc->complete = event_loop_base_complete;
+ ucc->can_be_deleted = event_loop_base_can_be_deleted;
object_class_property_add(klass, "aio-max-batch", "int",
event_loop_base_get_param,
diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
index d3750c8e76..20c9387654 100644
--- a/include/qemu/main-loop.h
+++ b/include/qemu/main-loop.h
@@ -26,9 +26,19 @@
#define QEMU_MAIN_LOOP_H
#include "block/aio.h"
+#include "qom/object.h"
+#include "sysemu/event-loop-base.h"
#define SIG_IPI SIGUSR1
+#define TYPE_MAIN_LOOP "main-loop"
+OBJECT_DECLARE_TYPE(MainLoop, MainLoopClass, MAIN_LOOP)
+
+struct MainLoop {
+ EventLoopBase parent_obj;
+};
+typedef struct MainLoop MainLoop;
+
/**
* qemu_init_main_loop: Set up the process so that it can run the main loop.
*
diff --git a/include/sysemu/event-loop-base.h b/include/sysemu/event-loop-base.h
index 8e77d8b69f..fced4c9fea 100644
--- a/include/sysemu/event-loop-base.h
+++ b/include/sysemu/event-loop-base.h
@@ -25,6 +25,7 @@ struct EventLoopBaseClass {
void (*init)(EventLoopBase *base, Error **errp);
void (*update_params)(EventLoopBase *base, Error **errp);
+ bool (*can_be_deleted)(EventLoopBase *base);
};
struct EventLoopBase {
diff --git a/meson.build b/meson.build
index 0a14e88ffc..b3472ae62a 100644
--- a/meson.build
+++ b/meson.build
@@ -2823,7 +2823,8 @@ libqemuutil = static_library('qemuutil',
sources: util_ss.sources() + stub_ss.sources() +
genh,
dependencies: [util_ss.dependencies(), libm,
threads, glib, socket, malloc, pixman])
qemuutil = declare_dependency(link_with: libqemuutil,
- sources: genh + version_res)
+ sources: genh + version_res,
+ dependencies: [event_loop_base])
if have_system or have_user
decodetree = generator(find_program('scripts/decodetree.py'),
diff --git a/qapi/qom.json b/qapi/qom.json
index a2439533c5..51f3acaad8 100644
--- a/qapi/qom.json
+++ b/qapi/qom.json
@@ -540,6 +540,16 @@
'*poll-grow': 'int',
'*poll-shrink': 'int' } }
+##
+# @MainLoopProperties:
+#
+# Properties for the main-loop object.
+#
+##
+{ 'struct': 'MainLoopProperties',
+ 'base': 'EventLoopBaseProperties',
+ 'data': {} }
+
##
# @MemoryBackendProperties:
#
@@ -830,6 +840,7 @@
{ 'name': 'input-linux',
'if': 'CONFIG_LINUX' },
'iothread',
+ 'main-loop',
{ 'name': 'memory-backend-epc',
'if': 'CONFIG_LINUX' },
'memory-backend-file',
@@ -895,6 +906,7 @@
'input-linux': { 'type': 'InputLinuxProperties',
'if': 'CONFIG_LINUX' },
'iothread': 'IothreadProperties',
+ 'main-loop': 'MainLoopProperties',
'memory-backend-epc': { 'type': 'MemoryBackendEpcProperties',
'if': 'CONFIG_LINUX' },
'memory-backend-file': 'MemoryBackendFileProperties',
diff --git a/util/main-loop.c b/util/main-loop.c
index b7b0ce4ca0..5b13f456fa 100644
--- a/util/main-loop.c
+++ b/util/main-loop.c
@@ -33,6 +33,7 @@
#include "qemu/error-report.h"
#include "qemu/queue.h"
#include "qemu/compiler.h"
+#include "qom/object.h"
#ifndef _WIN32
#include <sys/wait.h>
@@ -184,6 +185,61 @@ int qemu_init_main_loop(Error **errp)
return 0;
}
+static void main_loop_update_params(EventLoopBase *base, Error **errp)
+{
+ if (!qemu_aio_context) {
+ error_setg(errp, "qemu aio context not ready");
+ return;
+ }
+
+ aio_context_set_aio_params(qemu_aio_context, base->aio_max_batch, errp);
+}
+
+MainLoop *mloop;
+
+static void main_loop_init(EventLoopBase *base, Error **errp)
+{
+ MainLoop *m = MAIN_LOOP(base);
+
+ if (mloop) {
+ error_setg(errp, "only one main-loop instance allowed");
+ return;
+ }
+
+ main_loop_update_params(base, errp);
+
+ mloop = m;
+ return;
+}
+
+static bool main_loop_can_be_deleted(EventLoopBase *base)
+{
+ return false;
+}
+
+static void main_loop_class_init(ObjectClass *oc, void *class_data)
+{
+ EventLoopBaseClass *bc = EVENT_LOOP_BASE_CLASS(oc);
+
+ bc->init = main_loop_init;
+ bc->update_params = main_loop_update_params;
+ bc->can_be_deleted = main_loop_can_be_deleted;
+}
+
+static const TypeInfo main_loop_info = {
+ .name = TYPE_MAIN_LOOP,
+ .parent = TYPE_EVENT_LOOP_BASE,
+ .class_init = main_loop_class_init,
+ .instance_size = sizeof(MainLoop),
+};
+
+static void main_loop_register_types(void)
+{
+ type_register_static(&main_loop_info);
+}
+
+type_init(main_loop_register_types)
+
static int max_priority;
#ifndef _WIN32
--
2.35.1
