Re: [Qemu-block] [PATCH 12/18] iothread: detach all block devices before stopping them

[Paolo Bonzini]

On 14/10/2016 16:50, Fam Zheng wrote:
>> > +BdrvNextIterator it;
>> > +
>> > +for (bs = bdrv_first(); bs; bs = bdrv_next()) {
>> > +AioContext *ctx = bdrv_get_aio_context(bs);
> I have a strong feeling that we should 'continue' if ctx ==
> qemu_get_aio_context() - otherwise a lot of unnecessary (and somehow
> complicated) code will always run, even if user has no iothread.
> 
> Fam
> 
>> > +aio_context_acquire(ctx);
>> > +bdrv_set_aio_context(bs, qemu_get_aio_context());
>> > +aio_context_release(ctx);
>> > +}

Sounds good.

Paolo

Re: [Qemu-block] [PATCH 12/18] iothread: detach all block devices before stopping them

[Fam Zheng]

On Thu, 10/13 19:34, Paolo Bonzini wrote:
> Soon bdrv_drain will not call aio_poll itself on iothreads.  If block
> devices are left hanging off the iothread's AioContext, there will be no
> one to do I/O for those poor devices.
> 
> Signed-off-by: Paolo Bonzini 
> ---
>  iothread.c | 10 ++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/iothread.c b/iothread.c
> index 62c8796..8153e21 100644
> --- a/iothread.c
> +++ b/iothread.c
> @@ -16,6 +16,7 @@
>  #include "qom/object_interfaces.h"
>  #include "qemu/module.h"
>  #include "block/aio.h"
> +#include "block/block.h"
>  #include "sysemu/iothread.h"
>  #include "qmp-commands.h"
>  #include "qemu/error-report.h"
> @@ -199,6 +200,15 @@ IOThreadInfoList *qmp_query_iothreads(Error **errp)
>  void iothread_stop_all(void)
>  {
>  Object *container = object_get_objects_root();
> +BlockDriverState *bs;
> +BdrvNextIterator it;
> +
> +for (bs = bdrv_first(); bs; bs = bdrv_next()) {
> +AioContext *ctx = bdrv_get_aio_context(bs);

I have a strong feeling that we should 'continue' if ctx ==
qemu_get_aio_context() - otherwise a lot of unnecessary (and somehow
complicated) code will always run, even if user has no iothread.

Fam

> +aio_context_acquire(ctx);
> +bdrv_set_aio_context(bs, qemu_get_aio_context());
> +aio_context_release(ctx);
> +}
>  
>  object_child_foreach(container, iothread_stop, NULL);
>  }
> -- 
> 2.7.4
> 
> 

[Qemu-block] [PATCH 12/18] iothread: detach all block devices before stopping them

[Paolo Bonzini]

Soon bdrv_drain will not call aio_poll itself on iothreads.  If block
devices are left hanging off the iothread's AioContext, there will be no
one to do I/O for those poor devices.

Signed-off-by: Paolo Bonzini 
---
 iothread.c | 10 ++
 1 file changed, 10 insertions(+)

diff --git a/iothread.c b/iothread.c
index 62c8796..8153e21 100644
--- a/iothread.c
+++ b/iothread.c
@@ -16,6 +16,7 @@
 #include "qom/object_interfaces.h"
 #include "qemu/module.h"
 #include "block/aio.h"
+#include "block/block.h"
 #include "sysemu/iothread.h"
 #include "qmp-commands.h"
 #include "qemu/error-report.h"
@@ -199,6 +200,15 @@ IOThreadInfoList *qmp_query_iothreads(Error **errp)
 void iothread_stop_all(void)
 {
 Object *container = object_get_objects_root();
+BlockDriverState *bs;
+BdrvNextIterator it;
+
+for (bs = bdrv_first(); bs; bs = bdrv_next()) {
+AioContext *ctx = bdrv_get_aio_context(bs);
+aio_context_acquire(ctx);
+bdrv_set_aio_context(bs, qemu_get_aio_context());
+aio_context_release(ctx);
+}
 
 object_child_foreach(container, iothread_stop, NULL);
 }
-- 
2.7.4