[sheepdog] [PATCH 1/3] sheep: add helper function and clear connection directly when it is dead

[Yunkai Zhang]

On Fri, Jul 6, 2012 at 12:57 AM, MORITA Kazutaka
<morita.kazutaka at lab.ntt.co.jp> wrote:
> At Thu,  5 Jul 2012 18:34:10 +0800,
> Yunkai Zhang wrote:
>>
>> From: Yunkai Zhang <qiushu.zyk at taobao.com>
>>
>> When connection is dead, we should:
>>  1) do some clear actions about this connection.
>>  2) unregister it's fd from epoll.
>>  3) destroy this connection directly, since it's fd has been unregistered,
>>     sheep couldn't receive any new events of this fd.
>>     *Note*: If we use client_decref() instread of destroy_client(), this fd
>>     may not be destroyed when ci->refcnt is larger than 1, than this fd could
>>     not be closed in the future.
>>
>> Now I add a helper named clear_client() to do these works.
>>
>> Signed-off-by: Yunkai Zhang <qiushu.zyk at taobao.com>
>> ---
>>  sheep/sdnet.c |   20 ++++++++++++--------
>>  1 file changed, 12 insertions(+), 8 deletions(-)
>>
>> diff --git a/sheep/sdnet.c b/sheep/sdnet.c
>> index c13cdb0..b493428 100644
>> --- a/sheep/sdnet.c
>> +++ b/sheep/sdnet.c
>> @@ -370,6 +370,7 @@ static void requeue_request(struct request *req)
>>
>>  static void client_incref(struct client_info *ci);
>>  static void client_decref(struct client_info *ci);
>> +static void clear_client(struct client_info *ci);
>>
>>  static struct request *alloc_local_request(void *data, int data_length)
>>  {
>> @@ -473,11 +474,10 @@ void put_request(struct request *req)
>>               if (conn_tx_on(&ci->conn)) {
>>                       dprintf("connection seems to be dead\n");
>>                       free_request(req);
>> +                     clear_client(ci);
>
> We cannot free the client_info here because there may be other
> inflight requests which use it, no?


Yes, there may be other inflight request, but since conn_tx_on()
failed and then we can't send back response to the client, why not
free it? I think it can make program simple.


>
> Thanks,
>
> Kazutaka



-- 
Yunkai Zhang
Work at Taobao