#include "block/aio.h"
#include "block/block.h"
#include "sysemu/iothread.h"
-#include "qmp-commands.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"
#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)
qemu_cond_signal(&iothread->init_done_cond);
qemu_mutex_unlock(&iothread->init_done_lock);
- while (!atomic_read(&iothread->stopping)) {
+ while (iothread->running) {
aio_poll(iothread->ctx, true);
+
+ if (atomic_read(&iothread->worker_context)) {
+ GMainLoop *loop;
+
+ g_main_context_push_thread_default(iothread->worker_context);
+ iothread->main_loop =
+ g_main_loop_new(iothread->worker_context, TRUE);
+ loop = iothread->main_loop;
+
+ g_main_loop_run(iothread->main_loop);
+ iothread->main_loop = NULL;
+ g_main_loop_unref(loop);
+
+ g_main_context_pop_thread_default(iothread->worker_context);
+ }
}
rcu_unregister_thread();
return NULL;
}
-static int iothread_stop(Object *object, void *opaque)
+/* Runs in iothread_run() thread */
+static void iothread_stop_bh(void *opaque)
{
- IOThread *iothread;
+ IOThread *iothread = opaque;
- iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
- if (!iothread || !iothread->ctx) {
- return 0;
+ 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_notify(iothread->ctx);
+ aio_bh_schedule_oneshot(iothread->ctx, iothread_stop_bh, iothread);
qemu_thread_join(&iothread->thread);
- return 0;
+}
+
+static void iothread_instance_init(Object *obj)
+{
+ IOThread *iothread = IOTHREAD(obj);
+
+ iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT;
+ iothread->thread_id = -1;
}
static void iothread_instance_finalize(Object *obj)
{
IOThread *iothread = IOTHREAD(obj);
- iothread_stop(obj, NULL);
- qemu_cond_destroy(&iothread->init_done_cond);
- qemu_mutex_destroy(&iothread->init_done_lock);
- if (!iothread->ctx) {
- return;
+ iothread_stop(iothread);
+
+ if (iothread->thread_id != -1) {
+ qemu_cond_destroy(&iothread->init_done_cond);
+ qemu_mutex_destroy(&iothread->init_done_lock);
+ }
+ /*
+ * 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;
}
- aio_context_unref(iothread->ctx);
}
static void iothread_complete(UserCreatable *obj, Error **errp)
char *name, *thread_name;
iothread->stopping = false;
- iothread->thread_id = -1;
+ iothread->running = true;
iothread->ctx = aio_context_new(&local_error);
if (!iothread->ctx) {
error_propagate(errp, local_error);
return;
}
+ 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;
+ }
+
qemu_mutex_init(&iothread->init_done_lock);
qemu_cond_init(&iothread->init_done_cond);
+ iothread->once = (GOnce) G_ONCE_INIT;
/* This assumes we are called from a thread with useful CPU affinity for us
* to inherit.
qemu_mutex_unlock(&iothread->init_done_lock);
}
+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 = {
.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},
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;
return head;
}
-void iothread_stop_all(void)
+static gpointer iothread_g_main_context_init(gpointer opaque)
{
- Object *container = object_get_objects_root();
- BlockDriverState *bs;
- BdrvNextIterator it;
+ AioContext *ctx;
+ IOThread *iothread = opaque;
+ GSource *source;
- for (bs = bdrv_first(&it); bs; bs = bdrv_next(&it)) {
- AioContext *ctx = bdrv_get_aio_context(bs);
- if (ctx == qemu_get_aio_context()) {
- continue;
- }
- aio_context_acquire(ctx);
- bdrv_set_aio_context(bs, qemu_get_aio_context());
- aio_context_release(ctx);
- }
+ iothread->worker_context = g_main_context_new();
+
+ ctx = iothread_get_aio_context(iothread);
+ source = aio_get_g_source(ctx);
+ g_source_attach(source, iothread->worker_context);
+ g_source_unref(source);
+
+ aio_notify(iothread->ctx);
+ return NULL;
+}
+
+GMainContext *iothread_get_g_main_context(IOThread *iothread)
+{
+ g_once(&iothread->once, iothread_g_main_context_init, iothread);
+
+ 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);
+}
- object_child_foreach(container, iothread_stop, NULL);
+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));
}
projects / thirdparty / qemu.git / blobdiff