vl: Introduce shutdown_notifiers

[thirdparty/qemu.git] / iothread.c

diff --git a/iothread.c b/iothread.c
index 44c8944dc4ed023874d1f65fafd57df241a1216a..2fb1cdf55d10b882c78276221a0d0caaeba388a2 100644 (file)
--- a/iothread.c
+++ b/iothread.c
@@ -18,7 +18,8 @@
 #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"
@@ -30,11 +31,15 @@ typedef ObjectClass IOThreadClass;
 #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;
 
@@ -55,7 +60,7 @@ static void *iothread_run(void *opaque)
     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)) {
@@ -71,8 +76,6 @@ static void *iothread_run(void *opaque)
             g_main_loop_unref(loop);
 
             g_main_context_pop_thread_default(iothread->worker_context);
-            g_main_context_unref(iothread->worker_context);
-            iothread->worker_context = NULL;
         }
     }
 
@@ -80,21 +83,26 @@ static void *iothread_run(void *opaque)
     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->stopping = true;
-    aio_notify(iothread->ctx);
-    if (atomic_read(&iothread->main_loop)) {
+    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);
-    return 0;
 }
 
 static void iothread_instance_init(Object *obj)
@@ -102,19 +110,37 @@ 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)
@@ -124,7 +150,7 @@ 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);
@@ -312,25 +338,6 @@ IOThreadInfoList *qmp_query_iothreads(Error **errp)
     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);
-}
-
 static gpointer iothread_g_main_context_init(gpointer opaque)
 {
     AioContext *ctx;
@@ -354,3 +361,26 @@ GMainContext *iothread_get_g_main_context(IOThread *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));
+}
+
+/* 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));
+}