*
*/
+#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_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;
- bool blocking;
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 (!iothread->stopping) {
- aio_context_acquire(iothread->ctx);
- blocking = true;
- while (!iothread->stopping && aio_poll(iothread->ctx, blocking)) {
- /* Progress was made, keep going */
- blocking = false;
- }
- aio_context_release(iothread->ctx);
+ while (!atomic_read(&iothread->stopping)) {
+ aio_poll(iothread->ctx, true);
}
rcu_unregister_thread();
return NULL;
}
-static void iothread_instance_finalize(Object *obj)
+static int iothread_stop(Object *object, void *opaque)
{
- IOThread *iothread = IOTHREAD(obj);
+ IOThread *iothread;
- if (!iothread->ctx) {
- return;
+ iothread = (IOThread *)object_dynamic_cast(object, TYPE_IOTHREAD);
+ if (!iothread || !iothread->ctx) {
+ return 0;
}
iothread->stopping = true;
aio_notify(iothread->ctx);
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;
+}
+
+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;
+ }
aio_context_unref(iothread->ctx);
}
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);
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;
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, NULL);
+}
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