[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH V2] libxl: Set path to console on domain startup.
Anthony PERARD writes ("Re: [Xen-devel] [PATCH V2] libxl: Set path to console on domain startup."): > On Tue, Dec 16, 2014 at 09:30:28AM +0000, Ian Campbell wrote: > > Unless by "not running" you meant bottlenecked or not keeping up > > perhaps. > > Well, I did meant no xenconsoled process. But after, I also tried `kill > -STOP`, but the same things is happening. I think this is a bug. I imagine that you can cause `xl create -c' to malfunction too. > > > Or, should I set the callback to NULL and have the > > > domain_create_console_available event sent through > > > the callback set by libxl_event_register_callbacks()? > > > > That would make sense, except I don't see libxl_evdisable_foo for these > > events, so I'm not sure it is possible. > > Well, the domain_create_console_available event is report by > libxl__ao_progress_report which will either callback() or call > libxl__event_occurred(). So does not seams better to set callback to > NULL. The console available notification is only available via the ao progress mechanism. So you have to pass a non-NULL aop_console_how, and the notification will always be generated during the create. Your options for having the notification delivered are: I. aop_console_how->callback != NULL: libxl will call aop_console_how->callback(aop_console_how->for_callback) II. aop_console_how->callback == NULL: libxl will construct an libxl_event *event with event->domid = the domid of the domain being constructed event->domuuid = its uuid event->for_user = aop_console_how->for_event event->type = LIBXL_EVENT_TYPE_DOMAIN_CREATE_CONSOLE_AVAILABLE What happens to that event depends on whether and how libxl_event_register_callbacks has been called. II(a): If libxl_event_register_callbacks(,hooks,user) was called and also the bit is set ie !!(hooks->event_occurs_mask & (1UL << LIBXL_EVENT_TYPE_DOMAIN_CREATE_CONSOLE_AVAILABLE)): libxl will call hooks->event_occurs(user,event) II(b): If libxl_event_register_callbacks(,hooks,user) was NOT called or if the bit is clear: libxl will queue the event for retrieval by libxl_event_check or libxl_event-wait. (And if the application doesn't call those, the application will never be notified; the event will be retained until the libxl ctx is destroyed and then discarded.) I mention all of these for completeness, and for future reference for anyone reading the archives later. In libxl you want option I. Ian. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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