On Fri, Sep 22, 2017 at 11:38:31AM +0200, Paolo Bonzini wrote: > On 22/09/2017 11:36, Daniel P. Berrange wrote: > > On Fri, Sep 22, 2017 at 05:14:30PM +0800, Peter Xu wrote: > >> On Fri, Sep 22, 2017 at 10:04:33AM +0100, Daniel P. Berrange wrote: > >>> On Fri, Sep 22, 2017 at 04:56:10PM +0800, Peter Xu wrote: > >>>> IOThread is a general framework that contains IO loop environment and a > >>>> real thread behind. It's also good to be used internally inside qemu. > >>>> Provide some helpers for it to create iothreads to be used internally. > >>>> > >>>> Signed-off-by: Peter Xu <pet...@redhat.com> > >>>> --- > >>>> include/sysemu/iothread.h | 8 ++++++++ > >>>> iothread.c | 21 +++++++++++++++++++++ > >>>> 2 files changed, 29 insertions(+) > >>>> > >>>> diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h > >>>> index d2985b3..b07663f 100644 > >>>> --- a/include/sysemu/iothread.h > >>>> +++ b/include/sysemu/iothread.h > >>>> @@ -46,4 +46,12 @@ AioContext *iothread_get_aio_context(IOThread > >>>> *iothread); > >>>> void iothread_stop_all(void); > >>>> GMainContext *iothread_get_g_main_context(IOThread *iothread); > >>>> > >>>> +/* > >>>> + * Helpers used to allocate iothreads for internal use. These > >>>> + * iothreads will not be seen by monitor clients when query using > >>>> + * "query-iothreads". > >>>> + */ > >>>> +IOThread *iothread_create(const char *id, Error **errp); > >>>> +void iothread_destroy(IOThread *iothread); > >>>> + > >>>> #endif /* IOTHREAD_H */ > >>>> diff --git a/iothread.c b/iothread.c > >>>> index 44c8944..74e400c 100644 > >>>> --- a/iothread.c > >>>> +++ b/iothread.c > >>>> @@ -354,3 +354,24 @@ GMainContext *iothread_get_g_main_context(IOThread > >>>> *iothread) > >>>> > >>>> return iothread->worker_context; > >>>> } > >>>> + > >>>> +static Object *iothread_get_internal_parent(void) > >>>> +{ > >>>> + return container_get(object_get_root(), "/internal-iothreads"); > >>>> +} > >>> > >>> I tend to think we might benefit from having this generalized in the > >>> QOM API instead. We have object_get_objects_root() for things that > >>> are created by the mgmt app / user via CLI / QMP. A parallel method > >>> object_get_internal_root() could be useful for cases like this where > >>> we want to create user-creatable objects, but not have them be > >>> visible to the mgmt app / user, as that would confuse the mgmt app. > >>> > >>> Example for this scenario - libvirt calls query-iothreads to identify > >>> IO thread PIDs, and would get very unhappy if the IOThread used by > >>> the monitor would appear in that response, which is why Peter has > >>> put it under /internal-iothreads. I think this scenario will apply > >>> more broadly, so benefit from us having a general helper in QOM. > >> > >> Yeah, I can split the patch if we want it to be exposed to public. > >> > >> In that case, would the name "object_get_internal_root" be good? > > > > Yeah that's fine with me, but lets see if Paolo has any thoughts from > > the QOM side. > > No, I don't. However, I wonder if query-iothreads should have an > argument to include internal iothreads.
I guess it depends whether we consider use of iothreads for migration to be a private impl detail that may be ripped out & replaced at any time, or a semi-public detail that apps may rely on. Personally I would suggest it should be a private impl detail of migration code that is never exposed to anything outside QEMU, so we have flexibility to change it at will later. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|