Re: [Qemu-devel] [PATCH 2/3] net: Flush queues when runstate changes back to running

[zhanghailiang <zhang.zhanghailiang@huawei.com>]

On 2014/8/14 15:12, Gonglei (Arei) wrote:
> Hi,
>
>> Subject: [Qemu-devel] [PATCH 2/3] net: Flush queues when runstate changes
>> back to running
>>
>> When the runstate changes back to running, we definitely need to flush
>> queues to get packets flowing again.
>>
>> Here we implement this in the net layer:
>> (1) add a member 'VMChangeStateEntry *vmstate' to struct NICState,
>> Which will listen for VM runstate changes.
>
> Does this change will block migration during with different QEMU versions?
>

No, I have tested migration between qemu-1.5.1 with new qemu which has
merged this patches, everything seems ok!

>> (2) Register a handler function for VMstate change.
>> When vm changes back to running, we flush all queues in the callback function.
>>
>> Signed-off-by: zhanghailiang<zhang.zhanghailiang@huawei.com>
>> ---
>>   include/net/net.h |  1 +
>>   net/net.c         | 26 ++++++++++++++++++++++++++
>>   2 files changed, 27 insertions(+)
>>
>> diff --git a/include/net/net.h b/include/net/net.h
>> index 312f728..a294277 100644
>> --- a/include/net/net.h
>> +++ b/include/net/net.h
>> @@ -97,6 +97,7 @@ typedef struct NICState {
>>       NICConf *conf;
>>       void *opaque;
>>       bool peer_deleted;
>> +    VMChangeStateEntry *vmstate;
>>   } NICState;
>>
>>   NetClientState *qemu_find_netdev(const char *id);
>> diff --git a/net/net.c b/net/net.c
>> index 5bb2821..506e58f 100644
>> --- a/net/net.c
>> +++ b/net/net.c
>> @@ -242,6 +242,29 @@ NetClientState *qemu_new_net_client(NetClientInfo
>> *info,
>>       return nc;
>>   }
>>
>> +static void nic_vmstate_change_handler(void *opaque,
>> +                                       int running,
>> +                                       RunState state)
>> +{
>> +    NICState *nic = opaque;
>> +    NetClientState *nc;
>> +    int i, queues;
>> +
>> +    if (!running) {
>> +        return;
>> +    }
>> +
>> +    queues =  MAX(1, nic->conf->peers.queues);
>                ^
> A superfluous space.
>

Yes, Good catch, i will modify this. Thanks.