be8d853766
This is a stand-in for Michael Roth's QContext. I expect this to be replaced once QContext is completed. The IOThread object is an AioContext event loop thread. This patch adds the concept of multiple event loop threads, allowing users to define them. When SMP guests run on SMP hosts it makes sense to instantiate multiple IOThreads. This spreads event loop processing across multiple cores. Note that additional patches are required to actually bind a device to an IOThread. [Andreas Färber <afaerber@suse.de> pointed out that the embedded parent object instance should be called "parent_obj" and have a newline afterwards. This patch has been changed to reflect this. -- Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
121 lines
2.8 KiB
C
121 lines
2.8 KiB
C
/*
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* Event loop thread
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*
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* Copyright Red Hat Inc., 2013
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*
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* Authors:
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* Stefan Hajnoczi <stefanha@redhat.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2 or later.
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* See the COPYING file in the top-level directory.
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*
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*/
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#include "qom/object.h"
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#include "qom/object_interfaces.h"
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#include "qemu/module.h"
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#include "qemu/thread.h"
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#include "block/aio.h"
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#include "sysemu/iothread.h"
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#define IOTHREADS_PATH "/objects"
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typedef ObjectClass IOThreadClass;
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struct IOThread {
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Object parent_obj;
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QemuThread thread;
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AioContext *ctx;
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bool stopping;
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};
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#define IOTHREAD_GET_CLASS(obj) \
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OBJECT_GET_CLASS(IOThreadClass, obj, TYPE_IOTHREAD)
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#define IOTHREAD_CLASS(klass) \
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OBJECT_CLASS_CHECK(IOThreadClass, klass, TYPE_IOTHREAD)
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static void *iothread_run(void *opaque)
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{
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IOThread *iothread = opaque;
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while (!iothread->stopping) {
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aio_context_acquire(iothread->ctx);
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while (!iothread->stopping && aio_poll(iothread->ctx, true)) {
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/* Progress was made, keep going */
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}
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aio_context_release(iothread->ctx);
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}
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return NULL;
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}
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static void iothread_instance_finalize(Object *obj)
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{
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IOThread *iothread = IOTHREAD(obj);
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iothread->stopping = true;
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aio_notify(iothread->ctx);
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qemu_thread_join(&iothread->thread);
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aio_context_unref(iothread->ctx);
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}
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static void iothread_complete(UserCreatable *obj, Error **errp)
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{
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IOThread *iothread = IOTHREAD(obj);
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iothread->stopping = false;
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iothread->ctx = aio_context_new();
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/* This assumes we are called from a thread with useful CPU affinity for us
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* to inherit.
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*/
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qemu_thread_create(&iothread->thread, "iothread", iothread_run,
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iothread, QEMU_THREAD_JOINABLE);
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}
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static void iothread_class_init(ObjectClass *klass, void *class_data)
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{
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UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
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ucc->complete = iothread_complete;
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}
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static const TypeInfo iothread_info = {
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.name = TYPE_IOTHREAD,
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.parent = TYPE_OBJECT,
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.class_init = iothread_class_init,
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.instance_size = sizeof(IOThread),
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.instance_finalize = iothread_instance_finalize,
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.interfaces = (InterfaceInfo[]) {
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{TYPE_USER_CREATABLE},
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{}
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},
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};
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static void iothread_register_types(void)
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{
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type_register_static(&iothread_info);
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}
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type_init(iothread_register_types)
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IOThread *iothread_find(const char *id)
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{
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Object *container = container_get(object_get_root(), IOTHREADS_PATH);
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Object *child;
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child = object_property_get_link(container, id, NULL);
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if (!child) {
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return NULL;
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}
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return (IOThread *)object_dynamic_cast(child, TYPE_IOTHREAD);
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}
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char *iothread_get_id(IOThread *iothread)
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{
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return object_get_canonical_path_component(OBJECT(iothread));
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}
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AioContext *iothread_get_aio_context(IOThread *iothread)
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{
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return iothread->ctx;
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}
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