From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51807) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YGSA5-0006va-7X for qemu-devel@nongnu.org; Wed, 28 Jan 2015 07:56:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YGSA0-0000UY-0f for qemu-devel@nongnu.org; Wed, 28 Jan 2015 07:56:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:37439) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YGS9z-0000UM-Os for qemu-devel@nongnu.org; Wed, 28 Jan 2015 07:55:55 -0500 Date: Wed, 28 Jan 2015 13:55:44 +0100 From: Igor Mammedov Message-ID: <20150128135544.22995176@nial.brq.redhat.com> In-Reply-To: <54C8B552.3070903@redhat.com> References: <20150128072757.GA12987@redhat.com> <1422439417-5031-1-git-send-email-imammedo@redhat.com> <1422439417-5031-4-git-send-email-imammedo@redhat.com> <54C8B552.3070903@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 03/13] qom: add support for weak referenced object: aka UnownedObject List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: drjones@redhat.com, zhaoshenglong@huawei.com, claudio.fontana@huawei.com, qemu-devel@nongnu.org, marcel.a@redhat.com On Wed, 28 Jan 2015 11:09:22 +0100 Paolo Bonzini wrote: > > > On 28/01/2015 11:03, Igor Mammedov wrote: > > it adds support for weak reference model used by glib's > > GInitiallyUnowned to QEMU's QOM model. > > > > Signed-off-by: Igor Mammedov > > --- > > include/qom/object.h | 20 ++++++++++++++++++++ > > qom/object.c | 20 +++++++++++++++++++- > > 2 files changed, 39 insertions(+), 1 deletion(-) > > > > diff --git a/include/qom/object.h b/include/qom/object.h > > index 89c3092..e0e4cc8 100644 > > --- a/include/qom/object.h > > +++ b/include/qom/object.h > > @@ -1314,5 +1314,25 @@ int object_child_foreach(Object *obj, int (*fn)(Object *child, void *opaque), > > */ > > Object *container_get(Object *root, const char *path); > > > > +#define TYPE_UNOWNED_OBJECT "unowned-object" > > +#define UNOWNED_OBJECT(obj) \ > > + OBJECT_CHECK(UnownedObject, (obj), TYPE_UNOWNED_OBJECT) > > +#define UNOWNED_OBJECT_CLASS(klass) \ > > + OBJECT_CLASS_CHECK(UnownedObjectClass, (klass), TYPE_UNOWNED_OBJECT) > > +#define UNOWNED_OBJECT_GET_CLASS \ > > + OBJECT_GET_CLASS(UnownedObjectClass, (obj), TYPE_UNOWNED_OBJECT) > > +#define OBJECT_WEAK_REF (1UL << 31) > > + > > +typedef struct UnownedObjectClass > > +{ > > + /*< private >*/ > > + ObjectClass parent_class; > > +} UnownedObjectClass; > > + > > +typedef struct UnownedObject > > +{ > > + /*< private >*/ > > + Object parent_obj; > > +} UnownedObject; > > > > #endif > > diff --git a/qom/object.c b/qom/object.c > > index 1812c73..96842c7 100644 > > --- a/qom/object.c > > +++ b/qom/object.c > > @@ -705,6 +705,10 @@ void object_ref(Object *obj) > > if (!obj) { > > return; > > } > > + if (atomic_fetch_and(&obj->ref, ~OBJECT_WEAK_REF) & OBJECT_WEAK_REF) > > Please first do a non-atomic test, since this is unlikely to happen but > atomic_fetch_and is quite expensive (it compiles into a cmpxchg loop). sure > > Paolo > > > + { > > + return; > > + } > > atomic_inc(&obj->ref); > > } > > > > @@ -713,7 +717,7 @@ void object_unref(Object *obj) > > if (!obj) { > > return; > > } > > - g_assert(obj->ref > 0); > > + g_assert((obj->ref & ~OBJECT_WEAK_REF) > 0); > > > > /* parent always holds a reference to its children */ > > if (atomic_fetch_dec(&obj->ref) == 1) { > > @@ -1709,6 +1713,12 @@ static void object_instance_init(Object *obj) > > object_property_add_str(obj, "type", qdev_get_type, NULL, NULL); > > } > > > > + > > +static void unowned_object_instance_init(Object *obj) > > +{ > > + obj->ref |= OBJECT_WEAK_REF; > > +} > > + > > static void register_types(void) > > { > > static TypeInfo interface_info = { > > @@ -1724,8 +1734,16 @@ static void register_types(void) > > .abstract = true, > > }; > > > > + static TypeInfo unowned_object_info = { > > + .name = TYPE_UNOWNED_OBJECT, > > + .instance_size = sizeof(UnownedObject), > > + .instance_init = unowned_object_instance_init, > > + .abstract = true, > > + }; > > + > > type_interface = type_register_internal(&interface_info); > > type_register_internal(&object_info); > > + type_register_internal(&unowned_object_info); > > } > > > > type_init(register_types) > >