Upgrade version to 4.2.1

Change-Id: I38f1ed0c4da7315a6f8be766b3fc09531cb36313
Signed-off-by: wanchao-xu <wanchao.xu@samsung.com>

1 files changed, 386 insertions, 0 deletions

diff --git a/iothread.c b/iothread.c
new file mode 100644
index 000000000..7130be58e
--- /dev/null
+++ b/iothread.c
@@ -0,0 +1,386 @@
+/*
+ * Event loop thread
+ *
+ * Copyright Red Hat Inc., 2013
+ *
+ * Authors:
+ *  Stefan Hajnoczi   <stefanha@redhat.com>
+ *
+ * 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 "qemu/osdep.h"
+#include "qom/object.h"
+#include "qom/object_interfaces.h"
+#include "qemu/module.h"
+#include "block/aio.h"
+#include "block/block.h"
+#include "sysemu/iothread.h"
+#include "qapi/error.h"
+#include "qapi/qapi-commands-misc.h"
+#include "qemu/error-report.h"
+#include "qemu/rcu.h"
+#include "qemu/main-loop.h"
+
+typedef ObjectClass IOThreadClass;
+
+#define IOTHREAD_GET_CLASS(obj) \
+   OBJECT_GET_CLASS(IOThreadClass, obj, TYPE_IOTHREAD)
+#define IOTHREAD_CLASS(klass) \
+   OBJECT_CLASS_CHECK(IOThreadClass, klass, TYPE_IOTHREAD)
+
+#ifdef CONFIG_POSIX
+/* Benchmark results from 2016 on NVMe SSD drives show max polling times around
+ * 16-32 microseconds yield IOPS improvements for both iodepth=1 and iodepth=32
+ * workloads.
+ */
+#define IOTHREAD_POLL_MAX_NS_DEFAULT 32768ULL
+#else
+#define IOTHREAD_POLL_MAX_NS_DEFAULT 0ULL
+#endif
+
+static __thread IOThread *my_iothread;
+
+AioContext *qemu_get_current_aio_context(void)
+{
+    return my_iothread ? my_iothread->ctx : qemu_get_aio_context();
+}
+
+static void *iothread_run(void *opaque)
+{
+    IOThread *iothread = opaque;
+
+    rcu_register_thread();
+    /*
+     * g_main_context_push_thread_default() must be called before anything
+     * in this new thread uses glib.
+     */
+    g_main_context_push_thread_default(iothread->worker_context);
+    my_iothread = iothread;
+    iothread->thread_id = qemu_get_thread_id();
+    qemu_sem_post(&iothread->init_done_sem);
+
+    while (iothread->running) {
+        /*
+         * Note: from functional-wise the g_main_loop_run() below can
+         * already cover the aio_poll() events, but we can't run the
+         * main loop unconditionally because explicit aio_poll() here
+         * is faster than g_main_loop_run() when we do not need the
+         * gcontext at all (e.g., pure block layer iothreads).  In
+         * other words, when we want to run the gcontext with the
+         * iothread we need to pay some performance for functionality.
+         */
+        aio_poll(iothread->ctx, true);
+
+        /*
+         * We must check the running state again in case it was
+         * changed in previous aio_poll()
+         */
+        if (iothread->running && atomic_read(&iothread->run_gcontext)) {
+            g_main_loop_run(iothread->main_loop);
+        }
+    }
+
+    g_main_context_pop_thread_default(iothread->worker_context);
+    rcu_unregister_thread();
+    return NULL;
+}
+
+/* Runs in iothread_run() thread */
+static void iothread_stop_bh(void *opaque)
+{
+    IOThread *iothread = opaque;
+
+    iothread->running = false; /* stop iothread_run() */
+
+    if (iothread->main_loop) {
+        g_main_loop_quit(iothread->main_loop);
+    }
+}
+
+void iothread_stop(IOThread *iothread)
+{
+    if (!iothread->ctx || iothread->stopping) {
+        return;
+    }
+    iothread->stopping = true;
+    aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread);
+    qemu_thread_join(&iothread->thread);
+}
+
+static void iothread_instance_init(Object *obj)
+{
+    IOThread *iothread = IOTHREAD(obj);
+
+    iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT;
+    iothread->thread_id = -1;
+    qemu_sem_init(&iothread->init_done_sem, 0);
+    /* By default, we don't run gcontext */
+    atomic_set(&iothread->run_gcontext, 0);
+}
+
+static void iothread_instance_finalize(Object *obj)
+{
+    IOThread *iothread = IOTHREAD(obj);
+
+    iothread_stop(iothread);
+
+    /*
+     * Before glib2 2.33.10, there is a glib2 bug that GSource context
+     * pointer may not be cleared even if the context has already been
+     * destroyed (while it should).  Here let's free the AIO context
+     * earlier to bypass that glib bug.
+     *
+     * We can remove this comment after the minimum supported glib2
+     * version boosts to 2.33.10.  Before that, let's free the
+     * GSources first before destroying any GMainContext.
+     */
+    if (iothread->ctx) {
+        aio_context_unref(iothread->ctx);
+        iothread->ctx = NULL;
+    }
+    if (iothread->worker_context) {
+        g_main_context_unref(iothread->worker_context);
+        iothread->worker_context = NULL;
+        g_main_loop_unref(iothread->main_loop);
+        iothread->main_loop = NULL;
+    }
+    qemu_sem_destroy(&iothread->init_done_sem);
+}
+
+static void iothread_init_gcontext(IOThread *iothread)
+{
+    GSource *source;
+
+    iothread->worker_context = g_main_context_new();
+    source = aio_get_g_source(iothread_get_aio_context(iothread));
+    g_source_attach(source, iothread->worker_context);
+    g_source_unref(source);
+    iothread->main_loop = g_main_loop_new(iothread->worker_context, TRUE);
+}
+
+static void iothread_complete(UserCreatable *obj, Error **errp)
+{
+    Error *local_error = NULL;
+    IOThread *iothread = IOTHREAD(obj);
+    char *name, *thread_name;
+
+    iothread->stopping = false;
+    iothread->running = true;
+    iothread->ctx = aio_context_new(&local_error);
+    if (!iothread->ctx) {
+        error_propagate(errp, local_error);
+        return;
+    }
+
+    /*
+     * Init one GMainContext for the iothread unconditionally, even if
+     * it's not used
+     */
+    iothread_init_gcontext(iothread);
+
+    aio_context_set_poll_params(iothread->ctx,
+                                iothread->poll_max_ns,
+                                iothread->poll_grow,
+                                iothread->poll_shrink,
+                                &local_error);
+    if (local_error) {
+        error_propagate(errp, local_error);
+        aio_context_unref(iothread->ctx);
+        iothread->ctx = NULL;
+        return;
+    }
+
+    /* This assumes we are called from a thread with useful CPU affinity for us
+     * to inherit.
+     */
+    name = object_get_canonical_path_component(OBJECT(obj));
+    thread_name = g_strdup_printf("IO %s", name);
+    qemu_thread_create(&iothread->thread, thread_name, iothread_run,
+                       iothread, QEMU_THREAD_JOINABLE);
+    g_free(thread_name);
+    g_free(name);
+
+    /* Wait for initialization to complete */
+    while (iothread->thread_id == -1) {
+        qemu_sem_wait(&iothread->init_done_sem);
+    }
+}
+
+typedef struct {
+    const char *name;
+    ptrdiff_t offset; /* field's byte offset in IOThread struct */
+} PollParamInfo;
+
+static PollParamInfo poll_max_ns_info = {
+    "poll-max-ns", offsetof(IOThread, poll_max_ns),
+};
+static PollParamInfo poll_grow_info = {
+    "poll-grow", offsetof(IOThread, poll_grow),
+};
+static PollParamInfo poll_shrink_info = {
+    "poll-shrink", offsetof(IOThread, poll_shrink),
+};
+
+static void iothread_get_poll_param(Object *obj, Visitor *v,
+        const char *name, void *opaque, Error **errp)
+{
+    IOThread *iothread = IOTHREAD(obj);
+    PollParamInfo *info = opaque;
+    int64_t *field = (void *)iothread + info->offset;
+
+    visit_type_int64(v, name, field, errp);
+}
+
+static void iothread_set_poll_param(Object *obj, Visitor *v,
+        const char *name, void *opaque, Error **errp)
+{
+    IOThread *iothread = IOTHREAD(obj);
+    PollParamInfo *info = opaque;
+    int64_t *field = (void *)iothread + info->offset;
+    Error *local_err = NULL;
+    int64_t value;
+
+    visit_type_int64(v, name, &value, &local_err);
+    if (local_err) {
+        goto out;
+    }
+
+    if (value < 0) {
+        error_setg(&local_err, "%s value must be in range [0, %"PRId64"]",
+                   info->name, INT64_MAX);
+        goto out;
+    }
+
+    *field = value;
+
+    if (iothread->ctx) {
+        aio_context_set_poll_params(iothread->ctx,
+                                    iothread->poll_max_ns,
+                                    iothread->poll_grow,
+                                    iothread->poll_shrink,
+                                    &local_err);
+    }
+
+out:
+    error_propagate(errp, local_err);
+}
+
+static void iothread_class_init(ObjectClass *klass, void *class_data)
+{
+    UserCreatableClass *ucc = USER_CREATABLE_CLASS(klass);
+    ucc->complete = iothread_complete;
+
+    object_class_property_add(klass, "poll-max-ns", "int",
+                              iothread_get_poll_param,
+                              iothread_set_poll_param,
+                              NULL, &poll_max_ns_info, &error_abort);
+    object_class_property_add(klass, "poll-grow", "int",
+                              iothread_get_poll_param,
+                              iothread_set_poll_param,
+                              NULL, &poll_grow_info, &error_abort);
+    object_class_property_add(klass, "poll-shrink", "int",
+                              iothread_get_poll_param,
+                              iothread_set_poll_param,
+                              NULL, &poll_shrink_info, &error_abort);
+}
+
+static const TypeInfo iothread_info = {
+    .name = TYPE_IOTHREAD,
+    .parent = TYPE_OBJECT,
+    .class_init = iothread_class_init,
+    .instance_size = sizeof(IOThread),
+    .instance_init = iothread_instance_init,
+    .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)
+
+char *iothread_get_id(IOThread *iothread)
+{
+    return object_get_canonical_path_component(OBJECT(iothread));
+}
+
+AioContext *iothread_get_aio_context(IOThread *iothread)
+{
+    return iothread->ctx;
+}
+
+static int query_one_iothread(Object *object, void *opaque)
+{
+    IOThreadInfoList ***prev = opaque;
+    IOThreadInfoList *elem;
+    IOThreadInfo *info;
+    IOThread *iothread;
+
+    iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
+    if (!iothread) {
+        return 0;
+    }
+
+    info = g_new0(IOThreadInfo, 1);
+    info->id = iothread_get_id(iothread);
+    info->thread_id = iothread->thread_id;
+    info->poll_max_ns = iothread->poll_max_ns;
+    info->poll_grow = iothread->poll_grow;
+    info->poll_shrink = iothread->poll_shrink;
+
+    elem = g_new0(IOThreadInfoList, 1);
+    elem->value = info;
+    elem->next = NULL;
+
+    **prev = elem;
+    *prev = &elem->next;
+    return 0;
+}
+
+IOThreadInfoList *qmp_query_iothreads(Error **errp)
+{
+    IOThreadInfoList *head = NULL;
+    IOThreadInfoList **prev = &head;
+    Object *container = object_get_objects_root();
+
+    object_child_foreach(container, query_one_iothread, &prev);
+    return head;
+}
+
+GMainContext *iothread_get_g_main_context(IOThread *iothread)
+{
+    atomic_set(&iothread->run_gcontext, 1);
+    aio_notify(iothread->ctx);
+    return iothread->worker_context;
+}
+
+IOThread *iothread_create(const char *id, Error **errp)
+{
+    Object *obj;
+
+    obj = object_new_with_props(TYPE_IOTHREAD,
+                                object_get_internal_root(),
+                                id, errp, NULL);
+
+    return IOTHREAD(obj);
+}
+
+void iothread_destroy(IOThread *iothread)
+{
+    object_unparent(OBJECT(iothread));
+}
+
+/* Lookup IOThread by its id.  Only finds user-created objects, not internal
+ * iothread_create() objects. */
+IOThread *iothread_by_id(const char *id)
+{
+    return IOTHREAD(object_resolve_path_type(id, TYPE_IOTHREAD, NULL));
+}