* [Qemu-devel] [PATCH v2] qemu-iothread: IOThread supports the GMainContext event loop
@ 2017-08-15 7:28 Wang yong
2017-08-16 9:52 ` Stefan Hajnoczi
0 siblings, 1 reply; 3+ messages in thread
From: Wang yong @ 2017-08-15 7:28 UTC (permalink / raw)
To: pbonzini, stefanha, famz, jasowang
Cc: wang.yong155, wang.guang55, zhangchen.fnst, zhang.zhanghailiang,
lizhijian, qemu-devel
From: Wang Yong <wang.yong155@zte.com.cn>
IOThread uses AioContext event loop and does not run a GMainContext.
Therefore,chardev cannot work in IOThread,such as the chardev is
used for colo-compare packets reception.
This patch makes the IOThread run the GMainContext event loop,
chardev and IOThread can work together.
Signed-off-by: Wang Yong<wang.yong155@zte.com.cn>
Signed-off-by: Wang Guang<wang.guang55@zte.com.cn>
---
include/sysemu/iothread.h | 10 +++++++++
iothread.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 64 insertions(+)
diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
index e6da1a4..89e913c 100644
--- a/include/sysemu/iothread.h
+++ b/include/sysemu/iothread.h
@@ -20,10 +20,19 @@
#define TYPE_IOTHREAD "iothread"
typedef struct {
+ GMainContext *worker_context;
+ GMainLoop *main_loop;
+ GOnce once;
+
+ QEMUBH *bh;
+} GMainOnce;
+
+typedef struct {
Object parent_obj;
QemuThread thread;
AioContext *ctx;
+ GMainOnce thread_gonce;
QemuMutex init_done_lock;
QemuCond init_done_cond; /* is thread initialization done? */
bool stopping;
@@ -41,5 +50,6 @@ typedef struct {
char *iothread_get_id(IOThread *iothread);
AioContext *iothread_get_aio_context(IOThread *iothread);
void iothread_stop_all(void);
+GMainContext *iothread_get_g_main_context(IOThread *iothread);
#endif /* IOTHREAD_H */
diff --git a/iothread.c b/iothread.c
index beeb870..9995eb0 100644
--- a/iothread.c
+++ b/iothread.c
@@ -72,6 +72,9 @@ static int iothread_stop(Object *object, void *opaque)
return 0;
}
iothread->stopping = true;
+ if (iothread->thread_gonce.main_loop) {
+ g_main_loop_quit(iothread->thread_gonce.main_loop);
+ }
aio_notify(iothread->ctx);
qemu_thread_join(&iothread->thread);
return 0;
@@ -125,6 +128,7 @@ static void iothread_complete(UserCreatable *obj, Error **errp)
qemu_mutex_init(&iothread->init_done_lock);
qemu_cond_init(&iothread->init_done_cond);
+ iothread->thread_gonce.once = (GOnce) G_ONCE_INIT;
/* This assumes we are called from a thread with useful CPU affinity for us
* to inherit.
@@ -309,3 +313,53 @@ void iothread_stop_all(void)
object_child_foreach(container, iothread_stop, NULL);
}
+
+static void iothread_g_main_context_bh(void *opaque)
+{
+ GMainOnce *g = opaque;
+
+ qemu_bh_delete(g->bh);
+ g->bh = NULL;
+
+ g_main_context_push_thread_default(g->worker_context);
+
+ g->main_loop = g_main_loop_new(g->worker_context, TRUE);
+ g_main_loop_run(g->main_loop);
+
+ g_main_loop_unref(g->main_loop);
+ g->main_loop = NULL;
+
+ g_main_context_pop_thread_default(g->worker_context);
+ g_main_context_unref(g->worker_context);
+ g->worker_context = NULL;
+}
+
+static gpointer iothread_g_main_context_init(gpointer g_data)
+{
+ AioContext *ctx;
+ IOThread *iothread = (IOThread *)g_data;
+ GMainOnce *g = &iothread->thread_gonce;
+ GSource *source;
+
+ g->worker_context = g_main_context_new();
+
+ ctx = iothread_get_aio_context(iothread);
+ source = aio_get_g_source(ctx);
+ g_source_attach(source, g->worker_context);
+ g_source_unref(source);
+
+ g->bh = aio_bh_new(ctx,
+ iothread_g_main_context_bh, g);
+ qemu_bh_schedule(g->bh);
+
+ return (gpointer) g->worker_context;
+}
+
+GMainContext *iothread_get_g_main_context(IOThread *iothread)
+{
+ GMainOnce *g = &iothread->thread_gonce;
+
+ g_once(&g->once, iothread_g_main_context_init, iothread);
+
+ return (GMainContext *) g->once.retval;
+}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [PATCH v2] qemu-iothread: IOThread supports the GMainContext event loop
2017-08-15 7:28 [Qemu-devel] [PATCH v2] qemu-iothread: IOThread supports the GMainContext event loop Wang yong
@ 2017-08-16 9:52 ` Stefan Hajnoczi
2017-08-16 11:30 ` Paolo Bonzini
0 siblings, 1 reply; 3+ messages in thread
From: Stefan Hajnoczi @ 2017-08-16 9:52 UTC (permalink / raw)
To: Wang yong
Cc: pbonzini, stefanha, famz, jasowang, zhang.zhanghailiang,
lizhijian, wang.guang55, qemu-devel, zhangchen.fnst
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On Tue, Aug 15, 2017 at 03:28:15PM +0800, Wang yong wrote:
> From: Wang Yong <wang.yong155@zte.com.cn>
>
> IOThread uses AioContext event loop and does not run a GMainContext.
> Therefore,chardev cannot work in IOThread,such as the chardev is
> used for colo-compare packets reception.
>
> This patch makes the IOThread run the GMainContext event loop,
> chardev and IOThread can work together.
>
> Signed-off-by: Wang Yong<wang.yong155@zte.com.cn>
> Signed-off-by: Wang Guang<wang.guang55@zte.com.cn>
There is usually a space between the name and email address. Tools and
humans searching git log might not find you if you format the S-o-b line
without a space.
> ---
> include/sysemu/iothread.h | 10 +++++++++
> iothread.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 64 insertions(+)
>
> diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
> index e6da1a4..89e913c 100644
> --- a/include/sysemu/iothread.h
> +++ b/include/sysemu/iothread.h
> @@ -20,10 +20,19 @@
> #define TYPE_IOTHREAD "iothread"
>
> typedef struct {
> + GMainContext *worker_context;
> + GMainLoop *main_loop;
> + GOnce once;
> +
> + QEMUBH *bh;
> +} GMainOnce;
Please do not use the glib namespace (G*, g_*) because it's easy to
confuse GMainOnce with glib APIs like GOnce.
I suggest inlining these fields in IOThread instead of defining a new
struct.
> +
> +typedef struct {
> Object parent_obj;
>
> QemuThread thread;
> AioContext *ctx;
> + GMainOnce thread_gonce;
> QemuMutex init_done_lock;
> QemuCond init_done_cond; /* is thread initialization done? */
> bool stopping;
> @@ -41,5 +50,6 @@ typedef struct {
> char *iothread_get_id(IOThread *iothread);
> AioContext *iothread_get_aio_context(IOThread *iothread);
> void iothread_stop_all(void);
> +GMainContext *iothread_get_g_main_context(IOThread *iothread);
>
> #endif /* IOTHREAD_H */
> diff --git a/iothread.c b/iothread.c
> index beeb870..9995eb0 100644
> --- a/iothread.c
> +++ b/iothread.c
> @@ -72,6 +72,9 @@ static int iothread_stop(Object *object, void *opaque)
> return 0;
> }
> iothread->stopping = true;
> + if (iothread->thread_gonce.main_loop) {
> + g_main_loop_quit(iothread->thread_gonce.main_loop);
> + }
> aio_notify(iothread->ctx);
> qemu_thread_join(&iothread->thread);
> return 0;
> @@ -125,6 +128,7 @@ static void iothread_complete(UserCreatable *obj, Error **errp)
>
> qemu_mutex_init(&iothread->init_done_lock);
> qemu_cond_init(&iothread->init_done_cond);
> + iothread->thread_gonce.once = (GOnce) G_ONCE_INIT;
>
> /* This assumes we are called from a thread with useful CPU affinity for us
> * to inherit.
> @@ -309,3 +313,53 @@ void iothread_stop_all(void)
>
> object_child_foreach(container, iothread_stop, NULL);
> }
> +
> +static void iothread_g_main_context_bh(void *opaque)
> +{
> + GMainOnce *g = opaque;
> +
> + qemu_bh_delete(g->bh);
> + g->bh = NULL;
> +
> + g_main_context_push_thread_default(g->worker_context);
> +
> + g->main_loop = g_main_loop_new(g->worker_context, TRUE);
> + g_main_loop_run(g->main_loop);
Running the glib main loop from a BH function means deleted BHs can
never be freed in aio-posix.c:aio_bh_poll():
if (qemu_lockcnt_dec_if_lock(&ctx->list_lock)) {
bhp = &ctx->first_bh;
while (*bhp) {
bh = *bhp;
if (bh->deleted && !bh->scheduled) {
*bhp = bh->next;
g_free(bh);
} else {
bhp = &bh->next;
}
}
qemu_lockcnt_inc_and_unlock(&ctx->list_lock);
}
ctx->list_lock is held by iothread_run() -> aio_poll() so
qemu_lockcnt_dec_if_lock() always returns false.
Instead of running the glib event loop inside aio_poll() I would modify
iothread_run():
while (!atomic_read(&iothread->stopping)) {
if (atomic_read(&iothread->use_glib_event_loop)) {
iothread_glib_event_loop();
break;
}
aio_poll(iothread->ctx, true);
}
> +
> + g_main_loop_unref(g->main_loop);
> + g->main_loop = NULL;
> +
> + g_main_context_pop_thread_default(g->worker_context);
> + g_main_context_unref(g->worker_context);
> + g->worker_context = NULL;
> +}
> +
> +static gpointer iothread_g_main_context_init(gpointer g_data)
> +{
> + AioContext *ctx;
> + IOThread *iothread = (IOThread *)g_data;
No cast is necessary from void * to another pointer type in C. Please
remove the cast.
> + GMainOnce *g = &iothread->thread_gonce;
> + GSource *source;
> +
> + g->worker_context = g_main_context_new();
> +
> + ctx = iothread_get_aio_context(iothread);
> + source = aio_get_g_source(ctx);
> + g_source_attach(source, g->worker_context);
> + g_source_unref(source);
> +
> + g->bh = aio_bh_new(ctx,
> + iothread_g_main_context_bh, g);
> + qemu_bh_schedule(g->bh);
> +
> + return (gpointer) g->worker_context;
No cast is necessary from a pointer type to void * in C. Please remove
the cast.
> +}
> +
> +GMainContext *iothread_get_g_main_context(IOThread *iothread)
> +{
> + GMainOnce *g = &iothread->thread_gonce;
> +
> + g_once(&g->once, iothread_g_main_context_init, iothread);
> +
> + return (GMainContext *) g->once.retval;
No cast is necessary from a pointer type to void * in C. Please remove
the cast.
A dangling pointer is returned if this this function is called after
iothread_g_main_context_bh() has terminated. It would be safer to
return g->worker_context instead of g->once.retval.
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [PATCH v2] qemu-iothread: IOThread supports the GMainContext event loop
2017-08-16 9:52 ` Stefan Hajnoczi
@ 2017-08-16 11:30 ` Paolo Bonzini
0 siblings, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2017-08-16 11:30 UTC (permalink / raw)
To: Stefan Hajnoczi, Wang yong
Cc: stefanha, famz, jasowang, zhang.zhanghailiang, lizhijian,
wang.guang55, qemu-devel, zhangchen.fnst
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On 16/08/2017 11:52, Stefan Hajnoczi wrote:
>
> while (!atomic_read(&iothread->stopping)) {
> if (atomic_read(&iothread->use_glib_event_loop)) {
> iothread_glib_event_loop();
> break;
> }
>
> aio_poll(iothread->ctx, true);
> }
Alternatively:
while (!atomic_read(&iothread->stopping)) {
aio_poll(iothread->ctx, true);
}
if (atomic_read(&iothread->worker_context)) {
iothread_glib_event_loop();
}
and you can use this to enter the glib event loop:
iothread->stopping = true;
aio_notify(iothread->ctx);
(similar to iothread_stop).
Thanks,
Paolo
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2017-08-16 11:30 ` Paolo Bonzini
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