* Re: [Qemu-devel] [PATCH] qemu-iothread: IOThread supports the GMainContext event loop
2017-08-11 0:29 [Qemu-devel] [PATCH] qemu-iothread: IOThread supports the GMainContext event loop Wang yong
@ 2017-08-10 8:50 ` Paolo Bonzini
2017-08-10 9:17 ` Fam Zheng
1 sibling, 0 replies; 3+ messages in thread
From: Paolo Bonzini @ 2017-08-10 8:50 UTC (permalink / raw)
To: Wang yong
Cc: stefanha, famz, jasowang, wang guang55, zhangchen fnst,
zhang zhanghailiang, lizhijian, qemu-devel
----- Original Message -----
> From: "Wang yong" <wang.yong155@zte.com.cn>
> To: pbonzini@redhat.com, stefanha@redhat.com, famz@redhat.com, jasowang@redhat.com
> Cc: "wang yong155" <wang.yong155@zte.com.cn>, "wang guang55" <wang.guang55@zte.com.cn>, "zhangchen fnst"
> <zhangchen.fnst@cn.fujitsu.com>, "zhang zhanghailiang" <zhang.zhanghailiang@huawei.com>, lizhijian@cn.fujitsu.com,
> qemu-devel@nongnu.org
> Sent: Friday, August 11, 2017 2:29:15 AM
> Subject: [PATCH] qemu-iothread: IOThread supports the GMainContext event loop
>
> 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>
Nice. Just a note, I think an iothread should have its own (optional)
GMainContext accessed with iothread_get_g_main_context(iothread). When
you call it for the first time, the iothread:
1) creates a GMainContext
2) adds the AioContext as a GSource in the GMainContext
3) asks iothread_run to switch from the AioContext loop to the
GMainContext loop
To simplify thread-safety:
1) the GMainContext can be wrapped with a GOnce
2) the GOnce callback can leave steps 2 and 3 to a bottom half.
Paolo
> ---
> include/sysemu/iothread.h | 1 +
> iothread.c | 13 +++++++++++++
> 2 files changed, 14 insertions(+)
>
> diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
> index e6da1a4..ffe4e8a 100644
> --- a/include/sysemu/iothread.h
> +++ b/include/sysemu/iothread.h
> @@ -24,6 +24,7 @@ typedef struct {
>
> QemuThread thread;
> AioContext *ctx;
> + GMainLoop *loop;
> QemuMutex init_done_lock;
> QemuCond init_done_cond; /* is thread initialization done? */
> bool stopping;
> diff --git a/iothread.c b/iothread.c
> index beeb870..b6f3c3c 100644
> --- a/iothread.c
> +++ b/iothread.c
> @@ -46,6 +46,7 @@ AioContext *qemu_get_current_aio_context(void)
> static void *iothread_run(void *opaque)
> {
> IOThread *iothread = opaque;
> + GMainContext *context;
>
> rcu_register_thread();
>
> @@ -57,6 +58,15 @@ static void *iothread_run(void *opaque)
>
> while (!atomic_read(&iothread->stopping)) {
> aio_poll(iothread->ctx, true);
> +
> + context = iothread->ctx->source.context;
> + if (context) {
> + iothread->loop = g_main_loop_new(context, TRUE);
> + g_main_loop_run(iothread->loop);
> +
> + g_main_loop_unref(iothread->loop);
> + g_main_context_unref(context);
> + }
> }
>
> rcu_unregister_thread();
> @@ -72,6 +82,9 @@ static int iothread_stop(Object *object, void *opaque)
> return 0;
> }
> iothread->stopping = true;
> + if (iothread->loop) {
> + g_main_loop_quit(iothread->loop);
> + }
> aio_notify(iothread->ctx);
> qemu_thread_join(&iothread->thread);
> return 0;
> --
> 1.8.3.1
>
>
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Qemu-devel] [PATCH] qemu-iothread: IOThread supports the GMainContext event loop
2017-08-11 0:29 [Qemu-devel] [PATCH] qemu-iothread: IOThread supports the GMainContext event loop Wang yong
2017-08-10 8:50 ` Paolo Bonzini
@ 2017-08-10 9:17 ` Fam Zheng
1 sibling, 0 replies; 3+ messages in thread
From: Fam Zheng @ 2017-08-10 9:17 UTC (permalink / raw)
To: Wang yong
Cc: pbonzini, stefanha, jasowang, zhang.zhanghailiang, lizhijian,
wang.guang55, qemu-devel, zhangchen.fnst
On Fri, 08/11 08:29, 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>
> ---
> include/sysemu/iothread.h | 1 +
> iothread.c | 13 +++++++++++++
> 2 files changed, 14 insertions(+)
>
> diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
> index e6da1a4..ffe4e8a 100644
> --- a/include/sysemu/iothread.h
> +++ b/include/sysemu/iothread.h
> @@ -24,6 +24,7 @@ typedef struct {
>
> QemuThread thread;
> AioContext *ctx;
> + GMainLoop *loop;
> QemuMutex init_done_lock;
> QemuCond init_done_cond; /* is thread initialization done? */
> bool stopping;
> diff --git a/iothread.c b/iothread.c
> index beeb870..b6f3c3c 100644
> --- a/iothread.c
> +++ b/iothread.c
> @@ -46,6 +46,7 @@ AioContext *qemu_get_current_aio_context(void)
> static void *iothread_run(void *opaque)
> {
> IOThread *iothread = opaque;
> + GMainContext *context;
>
> rcu_register_thread();
>
> @@ -57,6 +58,15 @@ static void *iothread_run(void *opaque)
>
> while (!atomic_read(&iothread->stopping)) {
> aio_poll(iothread->ctx, true);
> +
> + context = iothread->ctx->source.context;
> + if (context) {
> + iothread->loop = g_main_loop_new(context, TRUE);
> + g_main_loop_run(iothread->loop);
> +
> + g_main_loop_unref(iothread->loop);
Is it better to set iothread->loop to NULL after unref? If in the future a
second place adds g_main_loop_quit(), it can coordinate with iothread_stop by
checking iothread->loop == NULL.
> + g_main_context_unref(context);
Where is the matching g_main_context_ref? I think the one reference in
iothread->loop goes away with g_main_loop_unref. Is this line unnecessary?
> + }
> }
>
> rcu_unregister_thread();
> @@ -72,6 +82,9 @@ static int iothread_stop(Object *object, void *opaque)
> return 0;
> }
> iothread->stopping = true;
> + if (iothread->loop) {
> + g_main_loop_quit(iothread->loop);
> + }
> aio_notify(iothread->ctx);
> qemu_thread_join(&iothread->thread);
> return 0;
> --
> 1.8.3.1
>
>
>
Though I haven't seen the chardev changes yet, the general idea looks good to
me.
Fam
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Qemu-devel] [PATCH] qemu-iothread: IOThread supports the GMainContext event loop
@ 2017-08-11 0:29 Wang yong
2017-08-10 8:50 ` Paolo Bonzini
2017-08-10 9:17 ` Fam Zheng
0 siblings, 2 replies; 3+ messages in thread
From: Wang yong @ 2017-08-11 0:29 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 | 1 +
iothread.c | 13 +++++++++++++
2 files changed, 14 insertions(+)
diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h
index e6da1a4..ffe4e8a 100644
--- a/include/sysemu/iothread.h
+++ b/include/sysemu/iothread.h
@@ -24,6 +24,7 @@ typedef struct {
QemuThread thread;
AioContext *ctx;
+ GMainLoop *loop;
QemuMutex init_done_lock;
QemuCond init_done_cond; /* is thread initialization done? */
bool stopping;
diff --git a/iothread.c b/iothread.c
index beeb870..b6f3c3c 100644
--- a/iothread.c
+++ b/iothread.c
@@ -46,6 +46,7 @@ AioContext *qemu_get_current_aio_context(void)
static void *iothread_run(void *opaque)
{
IOThread *iothread = opaque;
+ GMainContext *context;
rcu_register_thread();
@@ -57,6 +58,15 @@ static void *iothread_run(void *opaque)
while (!atomic_read(&iothread->stopping)) {
aio_poll(iothread->ctx, true);
+
+ context = iothread->ctx->source.context;
+ if (context) {
+ iothread->loop = g_main_loop_new(context, TRUE);
+ g_main_loop_run(iothread->loop);
+
+ g_main_loop_unref(iothread->loop);
+ g_main_context_unref(context);
+ }
}
rcu_unregister_thread();
@@ -72,6 +82,9 @@ static int iothread_stop(Object *object, void *opaque)
return 0;
}
iothread->stopping = true;
+ if (iothread->loop) {
+ g_main_loop_quit(iothread->loop);
+ }
aio_notify(iothread->ctx);
qemu_thread_join(&iothread->thread);
return 0;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2017-08-11 0:29 [Qemu-devel] [PATCH] qemu-iothread: IOThread supports the GMainContext event loop Wang yong
2017-08-10 8:50 ` Paolo Bonzini
2017-08-10 9:17 ` Fam Zheng
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