From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) by dpdk.org (Postfix) with ESMTP id 6D9DD7292 for ; Fri, 20 Apr 2018 17:40:02 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Apr 2018 08:40:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,302,1520924400"; d="scan'208";a="193077742" Received: from aburakov-mobl.ger.corp.intel.com (HELO [10.252.23.81]) ([10.252.23.81]) by orsmga004.jf.intel.com with ESMTP; 20 Apr 2018 08:39:59 -0700 To: "Tan, Jianfeng" , dev@dpdk.org Cc: thomas@monjalon.net References: <1520177405-59091-1-git-send-email-jianfeng.tan@intel.com> <1524156618-81402-1-git-send-email-jianfeng.tan@intel.com> <1524156618-81402-4-git-send-email-jianfeng.tan@intel.com> <59ed38b8-6ee5-5bc9-089c-c9a437c030c1@intel.com> <9553c783-9d56-786e-87ed-6fc96982e251@intel.com> <9253a7b4-6826-f5da-7d6b-f48ba3e8ee3d@intel.com> <278a73fd-f877-6113-d47c-160c4adb24bb@intel.com> From: "Burakov, Anatoly" Message-ID: Date: Fri, 20 Apr 2018 16:39:59 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <278a73fd-f877-6113-d47c-160c4adb24bb@intel.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit Subject: Re: [dpdk-dev] [PATCH v3 3/5] bus/vdev: bus scan by multi-process channel X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Apr 2018 15:40:03 -0000 On 20-Apr-18 4:32 PM, Tan, Jianfeng wrote: > > > On 4/20/2018 11:19 PM, Burakov, Anatoly wrote: >> On 20-Apr-18 3:28 PM, Tan, Jianfeng wrote: >>> >>> >>> On 4/20/2018 4:41 PM, Burakov, Anatoly wrote: >>>> On 19-Apr-18 5:50 PM, Jianfeng Tan wrote: >>>>> To scan the vdevs in primary, we send request to primary process >>>>> to obtain the names for vdevs. >>>>> >>>>> Only the name is shared from the primary. In probe(), the device >>>>> driver is supposed to locate (or request more) the detail >>>>> information from the primary. >>>>> >>>>> Signed-off-by: Jianfeng Tan >>>>> Reviewed-by: Qi Zhang >>>>> --- >>>> >>>> <...> >>>> >>>>> +static int >>>>> +vdev_action(const struct rte_mp_msg *mp_msg, const void *peer) >>>>> +{ >>>>> +    struct rte_vdev_device *dev; >>>>> +    struct rte_mp_msg mp_resp; >>>>> +    struct vdev_param *ou = (struct vdev_param *)&mp_resp.param; >>>>> +    const struct vdev_param *in = (const struct vdev_param >>>>> *)mp_msg->param; >>>>> +    const char *devname; >>>>> +    int num; >>>>> + >>>>> +    strcpy(mp_resp.name, "vdev"); >>>>> +    mp_resp.len_param = sizeof(*ou); >>>>> +    mp_resp.num_fds = 0; >>>>> + >>>>> +    switch (in->type) { >>>>> +    case VDEV_SCAN_REQ: >>>>> +        ou->type = VDEV_SCAN_ONE; >>>>> +        ou->num = 1; >>>>> +        num = 0; >>>>> + >>>>> +        rte_spinlock_lock(&vdev_device_list_lock); >>>>> +        TAILQ_FOREACH(dev, &vdev_device_list, next) { >>>>> +            devname = rte_vdev_device_name(dev); >>>>> +            if (strlen(devname) == 0) >>>>> +                VDEV_LOG(INFO, "vdev with no name is not sent"); >>>>> +            VDEV_LOG(INFO, "send vdev, %s", devname); >>>>> +            strncpy(ou->name, devname, RTE_DEV_NAME_MAX_LEN); >>>> >>>> Probably better use strlcpy as it always null-terminates. >>> >>> Yep. >>> >>>> >>>>> +            if (rte_mp_sendmsg(&mp_resp) < 0) >>>>> +                VDEV_LOG(ERR, "send vdev, %s, failed, %s", >>>>> +                     devname, strerror(rte_errno)); >>>>> +            num++; >>>> >>>> Some comments on what is going on here (why are we sending messages >>>> in response? why multiple? who will receive these messages?) would >>>> be nice. >>> >>> Yep, will explain that below. >>> >>>> I have a sneaking suspicion that you could've packed the response >>>> into one single message, but i'm not completely sure what is going >>>> on here, so maybe what you have here makes sense... >>> >>> What's happening here is that: >>> >>> a. Secondary process sends a sync request to ask for vdev in primary. >>> b. Primary process receives the request, and send vdevs one by one. >>> c. Primary process sends back reply, which indicates how many vdevs >>> are sent. >>> >>> The reason we don't pack all vdevs in the reply message is that, the >>> message length is RTE_MP_MAX_PARAM_LEN (256) in length. It's possible >>> that we cannot pack all vdevs in the single reply message. >>> >> >> OK. How does secondary know which vdevs are new and which aren't? > > This auto discovery is designed for secondary boot to know which vdevs > are used in primary. So they are all new to the secondary process. For > runtime vdev add in primary, we are going to rely on hotplug framework > to tell the news to secondary processes. > >> Does it even matter how many vdevs primary has sent? Correct me if i'm >> wrong, but it seems that you're only using sync request as kind of >> synchronization mechanism, and are not actually expecting any useful >> data in the reply. Which is OK, but in that case just don't bother >> sending any data in the reply in the first place :) > > I would like to keep this information, so that secondary process can > tell how many vdevs come from primary process (secondary process can > definitely iterate the vdev list to know, but it's that straightforward). > OK, no strong objections here :) -- Thanks, Anatoly