Re: [Qemu-devel] [PATCH v2 2/6] net: introduce lock to protect NetClientState's peer's access

[liu ping fan]

On Thu, Jun 20, 2013 at 3:46 PM, Stefan Hajnoczi <address@hidden> wrote:
> On Thu, Jun 20, 2013 at 02:30:30PM +0800, liu ping fan wrote:
>> On Tue, Jun 18, 2013 at 8:25 PM, Stefan Hajnoczi <address@hidden> wrote:
>> > On Thu, Jun 13, 2013 at 05:03:02PM +0800, Liu Ping Fan wrote:
>> >> + * And flush out peer's queue.
>> >> + */
>> >> +static void qemu_net_client_detach_flush(NetClientState *nc)
>> >> +{
>> >> +    NetClientState *peer;
>> >> +
>> >> +    /* reader of self's peer field , fixme? the deleters are not 
>> >> concurrent,
>> >> +         * so this pair lock can save.
>> >> +         */
>> >
>> > Indentation, also please resolve the fixme.
>> >
>> So, here can I take the assumption that the deleters are serialized by
>> biglock, and remove the lock following this comment?
>
> Ah, I understand the comment now.  Is there any advantage to dropping

:), only two atomic instruction in rare path.
> the lock?  IMO it's clearer to take the lock consistently instead of
> "optimizing" cases we think only get called from the main loop.

Reasonable, will keep them.