migration: consolidate VMStateField.start

[qemu.git] / iothread.c

diff --git a/iothread.c b/iothread.c
index bd7034481123849fa3bb0a2cbfca72a87a54bbd4..257b01d5f132b80b0cddf65a2b0e7aa099c96dbe 100644 (file)
--- a/iothread.c
+++ b/iothread.c
@@ -30,6 +30,12 @@ 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)
@@ -71,6 +77,13 @@ static int iothread_stop(Object *object, void *opaque)
     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);
@@ -98,6 +111,18 @@ static void iothread_complete(UserCreatable *obj, Error **errp)
         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);
 
@@ -120,10 +145,82 @@ static void iothread_complete(UserCreatable *obj, Error **errp)
     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 = {
@@ -131,6 +228,7 @@ 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},