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[Qemu-devel] [PATCH v3 1/2] iothread: stash thread ID away
From: |
Stefan Hajnoczi |
Subject: |
[Qemu-devel] [PATCH v3 1/2] iothread: stash thread ID away |
Date: |
Thu, 27 Feb 2014 11:48:41 +0100 |
Keep the thread ID around so we can report it via QMP.
There's only one problem: qemu_get_thread_id() (gettid() wrapper on
Linux) must be called from the thread itself. There is no way to get
the thread ID outside the thread.
This patch uses a condvar to wait for iothread_run() to populate the
thread_id inside the thread.
Signed-off-by: Stefan Hajnoczi <address@hidden>
---
iothread.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/iothread.c b/iothread.c
index 033de7f..0a3c048 100644
--- a/iothread.c
+++ b/iothread.c
@@ -25,7 +25,10 @@ struct IOThread {
Object parent;
QemuThread thread;
AioContext *ctx;
+ QemuMutex init_done_lock;
+ QemuCond init_done_cond; /* is thread initialization done? */
bool stopping;
+ int thread_id;
};
#define IOTHREAD_GET_CLASS(obj) \
@@ -37,6 +40,11 @@ static void *iothread_run(void *opaque)
{
IOThread *iothread = opaque;
+ 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);
while (!iothread->stopping && aio_poll(iothread->ctx, true)) {
@@ -54,6 +62,8 @@ static void iothread_instance_finalize(Object *obj)
iothread->stopping = true;
aio_notify(iothread->ctx);
qemu_thread_join(&iothread->thread);
+ qemu_cond_destroy(&iothread->init_done_cond);
+ qemu_mutex_destroy(&iothread->init_done_lock);
aio_context_unref(iothread->ctx);
}
@@ -63,12 +73,24 @@ static void iothread_complete(UserCreatable *obj, Error
**errp)
iothread->stopping = false;
iothread->ctx = aio_context_new();
+ iothread->thread_id = -1;
+
+ qemu_mutex_init(&iothread->init_done_lock);
+ qemu_cond_init(&iothread->init_done_cond);
/* This assumes we are called from a thread with useful CPU affinity for us
* to inherit.
*/
qemu_thread_create(&iothread->thread, iothread_run,
iothread, QEMU_THREAD_JOINABLE);
+
+ /* 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);
}
static void iothread_class_init(ObjectClass *klass, void *class_data)
--
1.8.5.3