From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by dpdk.org (Postfix) with ESMTP id 2AD4C25D9 for ; Wed, 8 Aug 2018 13:15:24 +0200 (CEST) Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A374D7A7E7; Wed, 8 Aug 2018 11:15:23 +0000 (UTC) Received: from ktraynor.remote.csb (ovpn-117-106.ams2.redhat.com [10.36.117.106]) by smtp.corp.redhat.com (Postfix) with ESMTP id 3D4861007090; Wed, 8 Aug 2018 11:15:20 +0000 (UTC) To: Qi Zhang , thomas@monjalon.net, konstantin.ananyev@intel.com, declan.doherty@intel.com, ferruh.yigit@intel.com Cc: dev@dpdk.org, benjamin.h.shelton@intel.com, narender.vangati@intel.com, beilei.xing@intel.com, wenzhuo.lu@intel.com, 0000-cover-letter.patch@dpdk.org References: <20180808070045.13334-1-qi.z.zhang@intel.com> From: Kevin Traynor Organization: Red Hat Message-ID: <516ab569-12d1-8c73-b14c-4a5784c71559@redhat.com> Date: Wed, 8 Aug 2018 12:15:20 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20180808070045.13334-1-qi.z.zhang@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.3 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Wed, 08 Aug 2018 11:15:23 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.2]); Wed, 08 Aug 2018 11:15:23 +0000 (UTC) for IP:'10.11.54.3' DOMAIN:'int-mx03.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'ktraynor@redhat.com' RCPT:'' Subject: Re: [dpdk-dev] [RFC 1/4] ethdev: claim device reset as async 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: Wed, 08 Aug 2018 11:15:24 -0000 On 08/08/2018 08:00 AM, Qi Zhang wrote: > rte_eth_dev_reset should be implemented in an async way since it is > possible be invoked in interrupt thread and sometimes to reset a > device need to wait for some dependency, for example, a VF expects > for PF ready, or a NIC function as part of a SOC wait for the whole > system reset complete, all these time consuming task will block the > the interrupt thread. > The patch claims rte_eth_dev_reset is an async function and introduce > a new event RTE_ETH_EVENT_RESET_COMPLETE. PMD should raise this event > when finish reset in background. The applicaiton should always wait > for this event before continue to configure and restart the device. > > Signed-off-by: Qi Zhang > --- > lib/librte_ethdev/rte_ethdev.h | 48 ++++++++++++++++++++++++++---------------- > 1 file changed, 30 insertions(+), 18 deletions(-) > > diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h > index 7070e9ab4..541b5161d 100644 > --- a/lib/librte_ethdev/rte_ethdev.h > +++ b/lib/librte_ethdev/rte_ethdev.h > @@ -1814,21 +1814,34 @@ void rte_eth_dev_close(uint16_t port_id); > * RTE_ETH_EVENT_INTR_RESET event is detected, but can also use it to start > * a port reset in other circumstances. > * > - * When this function is called, it first stops the port and then calls the > - * PMD specific dev_uninit( ) and dev_init( ) to return the port to initial > - * state, in which no Tx and Rx queues are setup, as if the port has been > - * reset and not started. The port keeps the port id it had before the > - * function call. > - * > - * After calling rte_eth_dev_reset( ), the application should use > - * rte_eth_dev_configure( ), rte_eth_rx_queue_setup( ), > - * rte_eth_tx_queue_setup( ), and rte_eth_dev_start( ) > - * to reconfigure the device as appropriate. > - * > - * Note: To avoid unexpected behavior, the application should stop calling > - * Tx and Rx functions before calling rte_eth_dev_reset( ). For thread > - * safety, all these controlling functions should be called from the same > - * thread. > + * @note > + * Device reset may have the dependency, for example, a VF reset expects > + * PF ready, or a NIC function as a part of a SOC need to wait for other > + * parts of the system be ready, these are time-consuming tasks and will > + * block current thread. > + * > + * So we claimed rte_eth_dev_reset as an async API, that makes things easy > + * for an application that what to reset the device from the interrupt > + * thread since typically a RTE_ETH_EVENT_INTR_RESET handler is invoked in > + * interrupt thread. > + * > + * PMD is responsrible to implement ops->dev_reset in an async way, it can > + * offload the whole task into a separate thread, or maybe just pending on > + * hardware interrupt as reset dependency ready or start a timely alarm > + * to poll register status as a background daemon. PMD is also responsible > + * to raise the RTE_ETH_EVENT_RESET_COMPLETE event to notify the application > + * when reset is complete. > + * > + * Application should not assume device reset is finished after > + * rte_eth_dev_reset return, it should always wait for a > + * RTE_ETH_EVENT_RESET_COMPLETE event and check the reset result. > + * If reset success, application should call rte_eth_dev_configure( ), > + * rte_eth_rx_queue_setup( ), rte_eth_tx_queue_setup( ), > + * and rte_eth_dev_start( ) to reconfigure the device as appropriate. > + * If you intend to make this change for 18.11, then I think you need to document it as part of 18.08. The function signature isn't changing, but the meaning of success is entirely different now. > + * @Note > + * To avoid unexpected behavior, the application should stop calling > + * Tx and Rx functions before calling rte_eth_dev_reset( ). > * > * @param port_id > * The port identifier of the Ethernet device. > @@ -1838,9 +1851,6 @@ void rte_eth_dev_close(uint16_t port_id); > * - (-EINVAL) if port identifier is invalid. > * - (-ENOTSUP) if hardware doesn't support this function. > * - (-EPERM) if not ran from the primary process. > - * - (-EIO) if re-initialisation failed or device is removed. > - * - (-ENOMEM) if the reset failed due to OOM. > - * - (-EAGAIN) if the reset temporarily failed and should be retried later. > */ > int rte_eth_dev_reset(uint16_t port_id); > > @@ -2574,6 +2584,8 @@ enum rte_eth_event_type { > /**< queue state event (enabled/disabled) */ > RTE_ETH_EVENT_INTR_RESET, > /**< reset interrupt event, sent to VF on PF reset */ > + RTE_ETH_EVENT_RESET_COMPLETE, > + /**< inform application that reset is completed */ > RTE_ETH_EVENT_VF_MBOX, /**< message from the VF received by PF */ > RTE_ETH_EVENT_MACSEC, /**< MACsec offload related event */ > RTE_ETH_EVENT_INTR_RMV, /**< device removal event */ >