Re: [Qemu-devel] [PATCH 3/3] iothread: delay the context release to finalize

[Peter Xu]

On Fri, Sep 22, 2017 at 09:09:22PM +0800, Fam Zheng wrote:
> On Fri, 09/22 16:56, Peter Xu wrote:
> > When gcontext is used with iothread, the context will be destroyed
> > during iothread_stop().  That's not good since sometimes we would like
> > to keep the resources until iothread is destroyed, but we may want to
> > stop the thread before that point.
> 
> Would be nice if you can also mention the glib bug that "required" this in the
> commit message.

I can add it, but I am not sure it's very closely related (and I'm
afraid that may confuse more people).  Say, even without that bug, I
would still think it not a good idea to free the context in the loop,
especially considering that we have the finalize function there.  Thanks,

> 
> Reviewed-by: Fam Zheng <address@hidden>
> 
> > 
> > Delay the destruction of gcontext to iothread finalize.  Then we can do:
> > 
> >   iothread_stop(thread);
> >   some_cleanup_on_resources();
> >   iothread_destroy(thread);
> > 
> > Signed-off-by: Peter Xu <address@hidden>
> > ---
> >  iothread.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git a/iothread.c b/iothread.c
> > index 894756b..b95369b 100644
> > --- a/iothread.c
> > +++ b/iothread.c
> > @@ -71,8 +71,6 @@ static void *iothread_run(void *opaque)
> >              g_main_loop_unref(loop);
> >  
> >              g_main_context_pop_thread_default(iothread->worker_context);
> > -            g_main_context_unref(iothread->worker_context);
> > -            iothread->worker_context = NULL;
> >          }
> >      }
> >  
> > @@ -117,6 +115,10 @@ static void iothread_instance_finalize(Object *obj)
> >      IOThread *iothread = IOTHREAD(obj);
> >  
> >      iothread_stop(iothread);
> > +    if (iothread->worker_context) {
> > +        g_main_context_unref(iothread->worker_context);
> > +        iothread->worker_context = NULL;
> > +    }
> >      qemu_cond_destroy(&iothread->init_done_cond);
> >      qemu_mutex_destroy(&iothread->init_done_lock);
> >      if (!iothread->ctx) {
> > -- 
> > 2.7.4
> > 
> > 

-- 
Peter Xu