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[Qemu-devel] [PULL 10/24] iothread: add I/O thread object
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PULL 10/24] iothread: add I/O thread object |
Date: |
Wed, 12 Mar 2014 11:29:18 +0100 |
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 <address@hidden> 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 <address@hidden>
---
Makefile.objs | 1 +
include/sysemu/iothread.h | 30 ++++++++++++
iothread.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 151 insertions(+)
create mode 100644 include/sysemu/iothread.h
create mode 100644 iothread.c
diff --git a/Makefile.objs b/Makefile.objs
index 5cd3d81..a6e0e2a 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -39,6 +39,7 @@ libcacard-y += libcacard/vcardt.o
ifeq ($(CONFIG_SOFTMMU),y)
common-obj-y = blockdev.o blockdev-nbd.o block/
+common-obj-y += iothread.o
common-obj-y += net/
common-obj-y += qdev-monitor.o device-hotplug.o
common-obj-$(CONFIG_WIN32) += os-win32.o
diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
new file mode 100644
index 0000000..a32214a
--- /dev/null
+++ b/include/sysemu/iothread.h
@@ -0,0 +1,30 @@
+/*
+ * Event loop thread
+ *
+ * Copyright Red Hat Inc., 2013
+ *
+ * Authors:
+ * Stefan Hajnoczi <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef IOTHREAD_H
+#define IOTHREAD_H
+
+#include "block/aio.h"
+
+#define TYPE_IOTHREAD "iothread"
+
+typedef struct IOThread IOThread;
+
+#define IOTHREAD(obj) \
+ OBJECT_CHECK(IOThread, obj, TYPE_IOTHREAD)
+
+IOThread *iothread_find(const char *id);
+char *iothread_get_id(IOThread *iothread);
+AioContext *iothread_get_aio_context(IOThread *iothread);
+
+#endif /* IOTHREAD_H */
diff --git a/iothread.c b/iothread.c
new file mode 100644
index 0000000..c2d7af7
--- /dev/null
+++ b/iothread.c
@@ -0,0 +1,120 @@
+/*
+ * Event loop thread
+ *
+ * Copyright Red Hat Inc., 2013
+ *
+ * Authors:
+ * Stefan Hajnoczi <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#include "qom/object.h"
+#include "qom/object_interfaces.h"
+#include "qemu/module.h"
+#include "qemu/thread.h"
+#include "block/aio.h"
+#include "sysemu/iothread.h"
+
+#define IOTHREADS_PATH "/objects"
+
+typedef ObjectClass IOThreadClass;
+struct IOThread {
+ Object parent_obj;
+
+ QemuThread thread;
+ AioContext *ctx;
+ bool stopping;
+};
+
+#define IOTHREAD_GET_CLASS(obj) \
+ OBJECT_GET_CLASS(IOThreadClass, obj, TYPE_IOTHREAD)
+#define IOTHREAD_CLASS(klass) \
+ OBJECT_CLASS_CHECK(IOThreadClass, klass, TYPE_IOTHREAD)
+
+static void *iothread_run(void *opaque)
+{
+ IOThread *iothread = opaque;
+
+ while (!iothread->stopping) {
+ aio_context_acquire(iothread->ctx);
+ while (!iothread->stopping && aio_poll(iothread->ctx, true)) {
+ /* Progress was made, keep going */
+ }
+ aio_context_release(iothread->ctx);
+ }
+ return NULL;
+}
+
+static void iothread_instance_finalize(Object *obj)
+{
+ IOThread *iothread = IOTHREAD(obj);
+
+ iothread->stopping = true;
+ aio_notify(iothread->ctx);
+ qemu_thread_join(&iothread->thread);
+ aio_context_unref(iothread->ctx);
+}
+
+static void iothread_complete(UserCreatable *obj, Error **errp)
+{
+ IOThread *iothread = IOTHREAD(obj);
+
+ iothread->stopping = false;
+ iothread->ctx = aio_context_new();
+
+ /* This assumes we are called from a thread with useful CPU affinity for us
+ * to inherit.
+ */
+ qemu_thread_create(&iothread->thread, iothread_run,
+ iothread, QEMU_THREAD_JOINABLE);
+}
+
+static void iothread_class_init(ObjectClass *klass, void *class_data)
+{
+ UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
+ ucc->complete = iothread_complete;
+}
+
+static const TypeInfo iothread_info = {
+ .name = TYPE_IOTHREAD,
+ .parent = TYPE_OBJECT,
+ .class_init = iothread_class_init,
+ .instance_size = sizeof(IOThread),
+ .instance_finalize = iothread_instance_finalize,
+ .interfaces = (InterfaceInfo[]) {
+ {TYPE_USER_CREATABLE},
+ {}
+ },
+};
+
+static void iothread_register_types(void)
+{
+ type_register_static(&iothread_info);
+}
+
+type_init(iothread_register_types)
+
+IOThread *iothread_find(const char *id)
+{
+ Object *container = container_get(object_get_root(), IOTHREADS_PATH);
+ Object *child;
+
+ child = object_property_get_link(container, id, NULL);
+ if (!child) {
+ return NULL;
+ }
+ return (IOThread *)object_dynamic_cast(child, TYPE_IOTHREAD);
+}
+
+char *iothread_get_id(IOThread *iothread)
+{
+ return object_get_canonical_path_component(OBJECT(iothread));
+}
+
+AioContext *iothread_get_aio_context(IOThread *iothread)
+{
+ return iothread->ctx;
+}
--
1.8.5.3
- [Qemu-devel] [PULL 00/24] Block patches for QEMU 2.0, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 01/24] qcow2-refcount: Sanitize refcount table entry, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 02/24] block: Update image size in bdrv_invalidate_cache(), Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 04/24] block: bs->drv may be NULL in bdrv_debug_resume(), Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 06/24] block: Rewrite the snapshot authorization mechanism for block filters., Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 07/24] object: add object_get_canonical_path_component(), Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 08/24] rfifolock: add recursive FIFO lock, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 10/24] iothread: add I/O thread object,
Stefan Hajnoczi <=
- [Qemu-devel] [PULL 09/24] aio: add aio_context_acquire() and aio_context_release(), Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 12/24] iothread: add "iothread" qdev property type, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 13/24] dataplane: replace internal thread with IOThread, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 17/24] qcow2: Don't write with BDRV_O_INCOMING, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 14/24] iothread: stash thread ID away, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 03/24] qcow2: Check bs->drv in copy_sectors(), Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 05/24] iotests: Test corruption during COW request, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 11/24] qdev: make get_pointer() handle temporary strings, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 15/24] qmp: add query-iothreads command, Stefan Hajnoczi, 2014/03/12
- [Qemu-devel] [PULL 21/24] block/raw-posix: bdrv_parse_filename() for floppy, Stefan Hajnoczi, 2014/03/12