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[Qemu-devel] [PATCH 1/4] iothread: replace init_done_cond with a semapho
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH 1/4] iothread: replace init_done_cond with a semaphore |
Date: |
Fri, 22 Feb 2019 11:14:10 +0800 |
Only sending an init-done message using lock+cond seems an overkill to
me. Replacing it with a simpler semaphore.
Meanwhile, init the semaphore unconditionally, then we can destroy it
unconditionally too in finalize which seems cleaner.
Signed-off-by: Peter Xu <address@hidden>
---
include/sysemu/iothread.h | 3 +--
iothread.c | 17 ++++-------------
2 files changed, 5 insertions(+), 15 deletions(-)
diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
index 8a7ac2c528..50411ba54a 100644
--- a/include/sysemu/iothread.h
+++ b/include/sysemu/iothread.h
@@ -27,8 +27,7 @@ typedef struct {
GMainContext *worker_context;
GMainLoop *main_loop;
GOnce once;
- QemuMutex init_done_lock;
- QemuCond init_done_cond; /* is thread initialization done? */
+ QemuSemaphore init_done_sem; /* is thread init done? */
bool stopping; /* has iothread_stop() been called? */
bool running; /* should iothread_run() continue? */
int thread_id;
diff --git a/iothread.c b/iothread.c
index e615b7ae52..6e297e9ef1 100644
--- a/iothread.c
+++ b/iothread.c
@@ -55,10 +55,8 @@ static void *iothread_run(void *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);
+ qemu_sem_post(&iothread->init_done_sem);
while (iothread->running) {
aio_poll(iothread->ctx, true);
@@ -115,6 +113,7 @@ static void iothread_instance_init(Object *obj)
iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT;
iothread->thread_id = -1;
+ qemu_sem_init(&iothread->init_done_sem, 0);
}
static void iothread_instance_finalize(Object *obj)
@@ -123,10 +122,6 @@ static void iothread_instance_finalize(Object *obj)
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
@@ -145,6 +140,7 @@ static void iothread_instance_finalize(Object *obj)
g_main_context_unref(iothread->worker_context);
iothread->worker_context = NULL;
}
+ qemu_sem_destroy(&iothread->init_done_sem);
}
static void iothread_complete(UserCreatable *obj, Error **errp)
@@ -173,8 +169,6 @@ static void iothread_complete(UserCreatable *obj, Error
**errp)
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
@@ -188,12 +182,9 @@ static void iothread_complete(UserCreatable *obj, Error
**errp)
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_sem_wait(&iothread->init_done_sem);
}
- qemu_mutex_unlock(&iothread->init_done_lock);
}
typedef struct {
--
2.17.1
[Qemu-devel] [PATCH 3/4] iothread: create main loop unconditionally, Peter Xu, 2019/02/21
[Qemu-devel] [PATCH 2/4] iothread: create the gcontext onconditionally, Peter Xu, 2019/02/21