Re: [PATCH v5 2/3] util/main-loop: Introduce the main loop into QOM

2022-04-24 Thread Markus Armbruster
Nicolas Saenz Julienne  writes:

> '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=
>
> Signed-off-by: Nicolas Saenz Julienne 
> Reviewed-by: Stefan Hajnoczi 

[...]

> 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.
> +#

Please add

   # Since: 7.1

> +##
> +{ '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',

[...]




[PATCH v5 2/3] util/main-loop: Introduce the main loop into QOM

2022-04-22 Thread Nicolas Saenz Julienne
'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=

Signed-off-by: Nicolas Saenz Julienne 
Reviewed-by: Stefan Hajnoczi 
---

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':