From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id EF3B9A0C41; Thu, 16 Sep 2021 10:02:12 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 6B4C34003F; Thu, 16 Sep 2021 10:02:12 +0200 (CEST) Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by mails.dpdk.org (Postfix) with ESMTP id 0E1524003E for ; Thu, 16 Sep 2021 10:02:10 +0200 (CEST) Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4H98Zx04Vtzbh7S; Thu, 16 Sep 2021 15:58:01 +0800 (CST) Received: from dggema767-chm.china.huawei.com (10.1.198.209) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.8; Thu, 16 Sep 2021 16:02:07 +0800 Received: from [10.66.74.184] (10.66.74.184) by dggema767-chm.china.huawei.com (10.1.198.209) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.8; Thu, 16 Sep 2021 16:02:07 +0800 To: Thomas Monjalon CC: , , References: <20210907034108.58763-1-lihuisong@huawei.com> <2757246.qzpMWD9H8a@thomas> <76ee3238-5d1f-70c5-3ec1-92662dea2185@huawei.com> <4929922.EBv6eS3NRu@thomas> From: Huisong Li Message-ID: <579c8578-01b6-3189-cc52-eec2c49a47bd@huawei.com> Date: Thu, 16 Sep 2021 16:01:57 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <4929922.EBv6eS3NRu@thomas> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.66.74.184] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggema767-chm.china.huawei.com (10.1.198.209) X-CFilter-Loop: Reflected Subject: Re: [dpdk-dev] [RFC V1] examples/l3fwd-power: fix memory leak for rte_pci_device X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Hi, Thomas The new comments are as follows, and look forward to your reply. Thanks! 在 2021/9/8 15:20, Thomas Monjalon 写道: > 08/09/2021 04:01, Huisong Li: >> 在 2021/9/7 16:53, Thomas Monjalon 写道: >>> 07/09/2021 05:41, Huisong Li: >>>> Calling rte_eth_dev_close() will release resources of eth device and close >>>> it. But rte_pci_device struct isn't released when app exit, which will lead >>>> to memory leak. >>> That's a PMD issue. >>> When the last port of a PCI device is closed, the device should be freed. >> Why is this a PMD problem? I don't understand. > In the PMD close function, freeing of PCI device must be managed, > so the app doesn't have to bother. I know what you mean. Currently, there are two ways to close PMD device (rte_eth_dev_close() and rte_dev_remove()). For rte_dev_remove(), eth device can be closed and rte_pci_device also can be freed, so it can make app not care about that. But dev_close() is only used to close eth device, and nothing about rte_pci_device is involved in the framework layer call stack of dev_close(). The rte_pci_device is allocated and initialized when the rte_pci_bus scans "/sys/bus/pci/devices" directory. Generally, the PMD of eth devices operates on the basis of eth devices, and rarely on rte_pci_device. And the rte_pci_device corresponding to the eth devices managed and processed by rte_pci_bus. So, PMD is closed only based on the port ID of the eth device, whilch only shuts down eth devices, not frees rte_pci_device and remove it from rte_pci_bus. > >> As far as I know, most apps or examples in the DPDK project have only >> one port for a pci device. > The number of ports per PCI device is driver-specific. > >> When the port is closed, the rte_pci_device should be freed. But none of >> the apps seem to do this. > That's because from the app point of view, only ports should be managed. > The hardware device is managed by the PMD. > Only drivers (PMDs) have to do the relation between class ports > and hardware devices. Yes. But the current app only closes the port to disable the PMD, and the rte_pci_device cannot be freed. Because rte_pci_device cannot be released in dev_close() of PMD, and is managed by framework layer. Btw. Excluding rte_dev_probe() and rte_dev_remove(),  it seems that the DPDK framework only automatically scans PCI devices, but does not automatically release PCI devices when the process exits. Above "automatic", I means that it doesn't involve apps or PMDs. > >>>> + /* Retrieve device address in eth device before closing it. */ >>>> + eth_dev = &rte_eth_devices[portid]; >>> You should not access this array, considered internal. >> We have to save the address of rte_device to free rte_pci_device before >> closing eth device. >> >> Because the the device address in rte_eth_dev struct will be set to a >> NULL after closing eth device. >> >> It's also handled in OVS in this way. > No you don't have to call rte_dev_remove at all from an app. > >>>> + rte_dev = eth_dev->device; >>>> rte_eth_dev_close(portid); >>>> + ret = rte_dev_remove(rte_dev); > > > .