From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ferruh Yigit <ferruh.yigit@intel.com>
Subject: Re: [PATCH v4 2/2] net/tap: add queues when attaching
 from secondary process
Date: Wed, 3 Oct 2018 17:28:06 +0100
Message-ID: <2c167597-e5fb-f5bf-3d2e-d807bb45da79@intel.com>
References: <1538047196-13789-2-git-send-email-rasland@mellanox.com>
 <2772955.aHLSG1IVkg@xps>
 <DB5PR05MB12544ED47F64DF56201187F7C2E80@DB5PR05MB1254.eurprd05.prod.outlook.com>
 <1606810.hPqmbmdGoK@xps>
Mime-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit
Cc: "dev@dpdk.org" <dev@dpdk.org>,
 "keith.wiles@intel.com" <keith.wiles@intel.com>,
 Shahaf Shuler <shahafs@mellanox.com>, Ori Kam <orika@mellanox.com>
To: Thomas Monjalon <thomas@monjalon.net>,
 Raslan Darawsheh <rasland@mellanox.com>
Return-path: <dev-bounces@dpdk.org>
Received: from mga18.intel.com (mga18.intel.com [134.134.136.126])
 by dpdk.org (Postfix) with ESMTP id 2979E1B10D
 for <dev@dpdk.org>; Wed,  3 Oct 2018 18:28:09 +0200 (CEST)
In-Reply-To: <1606810.hPqmbmdGoK@xps>
Content-Language: en-US
List-Id: DPDK patches and discussions <dev.dpdk.org>
List-Unsubscribe: <https://mails.dpdk.org/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://mails.dpdk.org/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <https://mails.dpdk.org/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

On 10/2/2018 12:38 PM, Thomas Monjalon wrote:
> 02/10/2018 12:50, Raslan Darawsheh:
>> From: Thomas Monjalon <thomas@monjalon.net> 
>>> 02/10/2018 12:34, Raslan Darawsheh:
>>>> @@ -2056,6 +2179,13 @@ rte_pmd_tap_probe(struct rte_vdev_device *dev)
>>>>
>>>>         TAP_LOG(NOTICE, "Initializing pmd_tap for %s as %s",
>>>>         
>>>>                 name, tap_name);
>>>>
>>>> +       /* Register IPC feed callback */
>>>> +       ret = rte_mp_action_register(TAP_MP_KEY, tap_mp_sync_queues);
>>>> +       if (ret < 0 && rte_errno != EEXIST) {
>>>> +               TAP_LOG(ERR, "%s: Failed to register IPC callback: %s",
>>>> +                       tuntap_name, strerror(rte_errno));
>>>> +               goto leave;
>>>> +       }
>>>>
>>>>         ret = eth_dev_tap_create(dev, tap_name, remote_iface, &user_mac,
>>>>         
>>>>                 ETH_TUNTAP_TYPE_TAP);
>>>
>>> Is it an issue registering tap_mp_sync_queues at each tap probing?
>>> Should we do it only once?
>>
>> It should be as of per device so we should do it for each port alone since several ports can have different queues.
>>
>> Moreover, if the port that has the registration was closed or unplugged we'll not be able to sync qeues for other ports. 
> 
> I think we should do register on first tap device probing and never unregisters.
> 
> Ferruh, any opinion?

I think it is good to unregister, but we need to keep number of active tap
devices, so register if "active_tap == 1", unregister when "active_tap == 0" ?