383 lines
10 KiB
C
383 lines
10 KiB
C
/*
|
|
* 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 "qmp-commands.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)
|
|
|
|
/* 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
|
|
|
|
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();
|
|
|
|
my_iothread = iothread;
|
|
qemu_mutex_lock(&iothread->init_done_lock);
|
|
iothread->thread_id = qemu_get_thread_id();
|
|
qemu_cond_signal(&iothread->init_done_cond);
|
|
qemu_mutex_unlock(&iothread->init_done_lock);
|
|
|
|
while (!atomic_read(&iothread->stopping)) {
|
|
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;
|
|
}
|
|
|
|
void iothread_stop(IOThread *iothread)
|
|
{
|
|
if (!iothread->ctx || iothread->stopping) {
|
|
return;
|
|
}
|
|
iothread->stopping = true;
|
|
aio_notify(iothread->ctx);
|
|
if (atomic_read(&iothread->main_loop)) {
|
|
g_main_loop_quit(iothread->main_loop);
|
|
}
|
|
qemu_thread_join(&iothread->thread);
|
|
}
|
|
|
|
static int iothread_stop_iter(Object *object, void *opaque)
|
|
{
|
|
IOThread *iothread;
|
|
|
|
iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
|
|
if (!iothread) {
|
|
return 0;
|
|
}
|
|
iothread_stop(iothread);
|
|
return 0;
|
|
}
|
|
|
|
static void iothread_instance_init(Object *obj)
|
|
{
|
|
IOThread *iothread = IOTHREAD(obj);
|
|
|
|
iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT;
|
|
}
|
|
|
|
static void iothread_instance_finalize(Object *obj)
|
|
{
|
|
IOThread *iothread = IOTHREAD(obj);
|
|
|
|
iothread_stop(iothread);
|
|
if (iothread->worker_context) {
|
|
g_main_context_unref(iothread->worker_context);
|
|
iothread->worker_context = NULL;
|
|
}
|
|
qemu_cond_destroy(&iothread->init_done_cond);
|
|
qemu_mutex_destroy(&iothread->init_done_lock);
|
|
if (!iothread->ctx) {
|
|
return;
|
|
}
|
|
aio_context_unref(iothread->ctx);
|
|
}
|
|
|
|
static void iothread_complete(UserCreatable *obj, Error **errp)
|
|
{
|
|
Error *local_error = NULL;
|
|
IOThread *iothread = IOTHREAD(obj);
|
|
char *name, *thread_name;
|
|
|
|
iothread->stopping = false;
|
|
iothread->thread_id = -1;
|
|
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.
|
|
*/
|
|
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 */
|
|
qemu_mutex_lock(&iothread->init_done_lock);
|
|
while (iothread->thread_id == -1) {
|
|
qemu_cond_wait(&iothread->init_done_cond,
|
|
&iothread->init_done_lock);
|
|
}
|
|
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 = {
|
|
.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;
|
|
}
|
|
|
|
void iothread_stop_all(void)
|
|
{
|
|
Object *container = object_get_objects_root();
|
|
BlockDriverState *bs;
|
|
BdrvNextIterator it;
|
|
|
|
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);
|
|
}
|
|
|
|
object_child_foreach(container, iothread_stop_iter, NULL);
|
|
}
|
|
|
|
static gpointer iothread_g_main_context_init(gpointer opaque)
|
|
{
|
|
AioContext *ctx;
|
|
IOThread *iothread = opaque;
|
|
GSource *source;
|
|
|
|
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);
|
|
}
|
|
|
|
void iothread_destroy(IOThread *iothread)
|
|
{
|
|
object_unparent(OBJECT(iothread));
|
|
}
|