OpenE2K/qemu-e2k
13
4
Fork 0
Code Issues 4 Pull Requests Projects 2 Releases Activity

iothread: replace init_done_cond with a semaphore

Browse Source 
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 <peterx@redhat.com>
Message-id: 20190306115532.23025-2-peterx@redhat.com
Message-Id: <20190306115532.23025-2-peterx@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Peter Xu 2019-03-06 19:55:28 +08:00 committed by Stefan Hajnoczi
parent bf4069fbd7
commit 21c4d15b47
2 changed files with 5 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/sysemu/iothread.h
View File

@ -27,8 +27,7 @@ typedef struct {
GMainContext *worker_context; GMainContext *worker_context;
GMainLoop *main_loop; GMainLoop *main_loop;
GOnce once; GOnce once;
QemuMutex init_done_lock; QemuSemaphore init_done_sem; /* is thread init done? */
QemuCond init_done_cond; /* is thread initialization done? */
bool stopping; /* has iothread_stop() been called? */ bool stopping; /* has iothread_stop() been called? */
bool running; /* should iothread_run() continue? */ bool running; /* should iothread_run() continue? */
int thread_id; int thread_id;

17
iothread.c
View File

@ -55,10 +55,8 @@ static void *iothread_run(void *opaque)
rcu_register_thread(); rcu_register_thread();
my_iothread = iothread; my_iothread = iothread;
qemu_mutex_lock(&iothread->init_done_lock);
iothread->thread_id = qemu_get_thread_id(); iothread->thread_id = qemu_get_thread_id();
qemu_cond_signal(&iothread->init_done_cond); qemu_sem_post(&iothread->init_done_sem);
qemu_mutex_unlock(&iothread->init_done_lock);
while (iothread->running) { while (iothread->running) {
aio_poll(iothread->ctx, true); 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->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT;
iothread->thread_id = -1; iothread->thread_id = -1;
qemu_sem_init(&iothread->init_done_sem, 0);
} }
static void iothread_instance_finalize(Object *obj) static void iothread_instance_finalize(Object *obj)
@ -123,10 +122,6 @@ static void iothread_instance_finalize(Object *obj)
iothread_stop(iothread); 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 * 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 * 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); g_main_context_unref(iothread->worker_context);
iothread->worker_context = NULL; iothread->worker_context = NULL;
} }
qemu_sem_destroy(&iothread->init_done_sem);
} }
static void iothread_complete(UserCreatable *obj, Error **errp) static void iothread_complete(UserCreatable *obj, Error **errp)
@ -173,8 +169,6 @@ static void iothread_complete(UserCreatable *obj, Error **errp)
return; return;
} }
qemu_mutex_init(&iothread->init_done_lock);
qemu_cond_init(&iothread->init_done_cond);
iothread->once = (GOnce) G_ONCE_INIT; iothread->once = (GOnce) G_ONCE_INIT;
/* This assumes we are called from a thread with useful CPU affinity for us /* 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); g_free(name);
/* Wait for initialization to complete */ /* Wait for initialization to complete */
qemu_mutex_lock(&iothread->init_done_lock);
while (iothread->thread_id == -1) { while (iothread->thread_id == -1) {
qemu_cond_wait(&iothread->init_done_cond, qemu_sem_wait(&iothread->init_done_sem);
&iothread->init_done_lock);
} }
qemu_mutex_unlock(&iothread->init_done_lock);
} }
typedef struct { typedef struct {