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Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting |
Date: |
Tue, 02 Jul 2013 11:36:01 -0500 |
User-agent: |
Notmuch/0.15.2+77~g661dcf8 (http://notmuchmail.org) Emacs/23.3.1 (x86_64-pc-linux-gnu) |
Paolo Bonzini <address@hidden> writes:
> Il 02/07/2013 16:47, Anthony Liguori ha scritto:
>> Jan Kiszka <address@hidden> writes:
>>
>>> Objects can soon be referenced/dereference outside the BQL. So we need
>>> to use atomics in object_ref/unref.
>>>
>>> Based on patch by Liu Ping Fan.
>>>
>>> Signed-off-by: Jan Kiszka <address@hidden>
>>> ---
>>> qom/object.c | 5 ++---
>>> 1 files changed, 2 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/qom/object.c b/qom/object.c
>>> index 803b94b..a76a30b 100644
>>> --- a/qom/object.c
>>> +++ b/qom/object.c
>>> @@ -683,16 +683,15 @@ GSList *object_class_get_list(const char
>>> *implements_type,
>>>
>>> void object_ref(Object *obj)
>>> {
>>> - obj->ref++;
>>> + __sync_fetch_and_add(&obj->ref, 1);
>>> }
>>>
>>> void object_unref(Object *obj)
>>> {
>>> g_assert(obj->ref > 0);
>>> - obj->ref--;
>>>
>>> /* parent always holds a reference to its children */
>>> - if (obj->ref == 0) {
>>> + if (__sync_sub_and_fetch(&obj->ref, 1) == 0) {
>>> object_finalize(obj);
>>> }
>>> }
>>
>> Should we introduce something akin to kref now that referencing counting
>> has gotten fancy?
>
> I'm not a big fan of kref (it seems _too_ thin a wrapper to me, i.e. it
> doesn't really wrap enough to be useful), but I wouldn't oppose it if
> someone else does it.
I had honestly hoped Object was light enough to be used for this
purpose. What do you think?
Regards,
Anthony Liguori
>
> Paolo
Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting, Anthony Liguori, 2013/07/02
- Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting, Paolo Bonzini, 2013/07/02
- Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting,
Anthony Liguori <=
- Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting, liu ping fan, 2013/07/02
- Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting, Andreas Färber, 2013/07/03
- Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting, liu ping fan, 2013/07/04
- Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting, Andreas Färber, 2013/07/04
- Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting, liu ping fan, 2013/07/04
Re: [Qemu-devel] [PATCH] qom: Use atomics for object refcounting, Paolo Bonzini, 2013/07/04