> > > >>>>>>>>> In the proactive error handling mode, the PMD will set the data path > >>>>>>>>> pointers to dummy functions and then try recovery, in this period > >>>>>>>>> the > >>>>>>>>> application may still invoking data path API. This will introduce a > >>>>>>>>> race-condition with data path which may lead to crash [1]. > >>>>>>>>> > >>>>>>>>> Although the PMD added delay after setting data path pointers to > >>>>>>>>> cover > >>>>>>>>> the above race-condition, it reduces the probability, but it doesn't > >>>>>>>>> solve the problem. > >>>>>>>>> > >>>>>>>>> To solve the race-condition problem fundamentally, the following > >>>>>>>>> requirements are added: > >>>>>>>>> 1. The PMD should set the data path pointers to dummy functions > >>>>>>>>> after > >>>>>>>>> report RTE_ETH_EVENT_ERR_RECOVERING event. > >>>>>>>>> 2. The application should stop data path API invocation when process > >>>>>>>>> the RTE_ETH_EVENT_ERR_RECOVERING event. > >>>>>>>>> 3. The PMD should set the data path pointers to valid functions > >>>>>>>>> before > >>>>>>>>> report RTE_ETH_EVENT_RECOVERY_SUCCESS event. > >>>>>>>>> 4. The application should enable data path API invocation when > >>>>>>>>> process > >>>>>>>>> the RTE_ETH_EVENT_RECOVERY_SUCCESS event. > >>>>>>>>> > >>>>>>> > >>>>>>> How this is solving the race-condition, by pushing responsibility to > >>>>>>> stop data path to application? > >>>>>> > >>>>>> Exactly, it becomes application responsibility to make sure data-path > >>>>>> is > >>>>>> stopped/suspended before recovery will continue. > >>>>>> > >>>>> > >>>>> From documentation of the feature: > >>>>> > >>>>> `` > >>>>> Because the PMD recovers automatically, > >>>>> the application can only sense that the data flow is disconnected for a > >>>>> while and the control API returns an error in this period. > >>>>> > >>>>> In order to sense the error happening/recovering, as well as to restore > >>>>> some additional configuration, three events are available: > >>>>> `` > >>>>> > >>>>> It looks like initial design is to use events mainly inform application > >>>>> about what happened and mainly for re-configuration. > >>>>> > >>>>> Although I am don't disagree to involve the application, I am not sure > >>>>> that is part of current design. > >>>> > >>>> I thought we all agreed that initial design contain some fallacies that > >>>> need to fixed, no? > >>>> Statement that with current rte_ethdev design error recovery can be done > >>>> without interaction with the app (to stop/suspend data/control path) > >>>> is the main one I think. > >>>> It needs some interaction with app layer, one way or another. > >>>> > >>>>>>> > >>>>>>> What if application is not interested in recovery modes at all and not > >>>>>>> registered any callback for the recovery? > >>>>>> > >>>>>> > >>>>>> Are you saying there is no way for application to disable > >>>>>> automatic recovery in PMD if it is not interested > >>>>>> (or can't full-fill per-requesties for it)? > >>>>>> If so, then yes it is a problem and we need to fix it. > >>>>>> I assumed that such mechanism to disable unwanted events already > >>>>>> exists, > >>>>>> but I can't find anything. > >>>>>> Wonder what would be the easiest way here - can PMD make a decision > >>>>>> based on callback return value, or do we need a new API to > >>>>>> enable/disable callbacks, or ...? > >>>>>> > >>>>>> > >>>>> > >>>>> As far as I can see automatic recovery is not configurable by app. > >>>>> > >>>>> But that is not all, PMD sends events to application but PMD can't know > >>>>> if application is handling them or not, so with current design PMD can't > >>>>> rely on to app. > >>>> > >>>> Well, PMD invokes user provided callback. > >>>> One way to fix that problem - if there is no callback provided, > >>>> or callback returns an error code - PMD can assume that recovery > >>>> should not be done. > >>>> That is probably not the best design choice, but at least it will allow > >>>> to fix the problem without too many changes and introducing new API. > >>>> That could be sort of a 'quick fix'. > >>>> In a meanwhile we can think about new/better approach for that. > >>>> > >>> > >>> -rc2 for 23.03 is a few days away. > >>> > >>> What do you think to have 'quick fix' as modifying how driver updates > >>> burst ops to prevent the race condition, for this release? > > The 'quick fix', do you mean only update function pointer (without rxq > setting) ? > Currently the PMDs which announced support "proactive error handling mode" > already > do this.
Really sorry guys, I was too fast on the keyboard, and didn't read properly what Ferruh suggested. Reading it once again - no I don not agree with that. It wouldn't fix anything, but will just add extra mess into the code. Sorry again for the wrong reply. Konstantin > > >>> > >>> And plan a design update for the next release? > >> +1 on the overall approach. > > > > Yep, agree. > > Hope for better solution. > And also, I notice only the openvswitch (from all open-source software which > based-on DPDK) > registers RTE_ETH_EVENT_INTR_RESET callback . > > Therefore, hope we build a recovery framework at the DPDK SDK level and be > compatible > with RTE_ETH_EVENT_INTR_RESET and RTE_ETH_EVENT_ERR_RECOVERING mechanism. > > > > >> > >>> > >>> > >>>>> > >>>>>>> I think driver should not rely on application for this, unless > >>>>>>> application explicitly says (to driver) that it is handling recovery, > >>>>>>> right now there is no way for driver to know this. > >>>>>> > >>>>>> I think it is visa-versa: > >>>>>> application should not enable auto-recovery if it can't meet > >>>>>> per-requeststies for it (provide appropriate callback). > >>>>>> > >>>>> > >>>>> I agree on above, we are saying similar thing in different perspective. > >>>> > >>>> Ok, that's good we are on the same page. > >>>> > >>>> > >>>>> > >>>>>> > >>>>>>> > >>>>>>>>> Also, this patch introduce a driver internal function > >>>>>>>>> rte_eth_fp_ops_setup which used as an help function for PMD. > >>>>>>>>> > >>>>>>>>> [1] > >>>>>>>>> http://patchwork.dpdk.org/project/dpdk/patch/20230220060839.1267349-2-ashok.k.kal...@intel.com/ > >>>>>>>>> > >>>>>>>>> Fixes: eb0d471a8941 ("ethdev: add proactive error handling mode") > >>>>>>>>> Cc: sta...@dpdk.org > >>>>>>>>> > >>>>>>>>> Signed-off-by: Chengwen Feng <fengcheng...@huawei.com> > >>>>>>>>> --- > >>>>>>>>> doc/guides/prog_guide/poll_mode_drv.rst | 20 +++++++--------- > >>>>>>>>> lib/ethdev/ethdev_driver.c | 8 +++++++ > >>>>>>>>> lib/ethdev/ethdev_driver.h | 10 ++++++++ > >>>>>>>>> lib/ethdev/rte_ethdev.h | 32 > >>>>>>>>> +++++++++++++++---------- > >>>>>>>>> lib/ethdev/version.map | 1 + > >>>>>>>>> 5 files changed, 46 insertions(+), 25 deletions(-) > >>>>>>>>> > >>>>>>>>> diff --git a/doc/guides/prog_guide/poll_mode_drv.rst > >>>>>>>>> b/doc/guides/prog_guide/poll_mode_drv.rst > >>>>>>>>> index c145a9066c..e380ff135a 100644 > >>>>>>>>> --- a/doc/guides/prog_guide/poll_mode_drv.rst > >>>>>>>>> +++ b/doc/guides/prog_guide/poll_mode_drv.rst > >>>>>>>>> @@ -638,14 +638,9 @@ different from the application invokes recovery > >>>>>>>>> in PASSIVE mode, > >>>>>>>>> the PMD automatically recovers from error in PROACTIVE mode, > >>>>>>>>> and only a small amount of work is required for the application. > >>>>>>>>> > >>>>>>>>> -During error detection and automatic recovery, > >>>>>>>>> -the PMD sets the data path pointers to dummy functions > >>>>>>>>> -(which will prevent the crash), > >>>>>>>>> -and also make sure the control path operations fail with a return > >>>>>>>>> code ``-EBUSY``. > >>>>>>>>> - > >>>>>>>>> -Because the PMD recovers automatically, > >>>>>>>>> -the application can only sense that the data flow is disconnected > >>>>>>>>> for a while > >>>>>>>>> -and the control API returns an error in this period. > >>>>>>>>> +During error detection and automatic recovery, the PMD sets the > >>>>>>>>> data path > >>>>>>>>> +pointers to dummy functions and also make sure the control path > >>>>>>>>> operations > >>>>>>>>> +failed with a return code ``-EBUSY``. > >>>>>>>>> > >>>>>>>>> In order to sense the error happening/recovering, > >>>>>>>>> as well as to restore some additional configuration, > >>>>>>>>> @@ -653,9 +648,9 @@ three events are available: > >>>>>>>>> > >>>>>>>>> ``RTE_ETH_EVENT_ERR_RECOVERING`` > >>>>>>>>> Notify the application that an error is detected > >>>>>>>>> - and the recovery is being started. > >>>>>>>>> + and the recovery is about to start. > >>>>>>>>> Upon receiving the event, the application should not invoke > >>>>>>>>> - any control path function until receiving > >>>>>>>>> + any control and data path API until receiving > >>>>>>>>> ``RTE_ETH_EVENT_RECOVERY_SUCCESS`` or > >>>>>>>>> ``RTE_ETH_EVENT_RECOVERY_FAILED`` event. > >>>>>>>>> > >>>>>>>>> .. note:: > >>>>>>>>> @@ -666,8 +661,9 @@ three events are available: > >>>>>>>>> > >>>>>>>>> ``RTE_ETH_EVENT_RECOVERY_SUCCESS`` > >>>>>>>>> Notify the application that the recovery from error is > >>>>>>>>> successful, > >>>>>>>>> - the PMD already re-configures the port, > >>>>>>>>> - and the effect is the same as a restart operation. > >>>>>>>>> + the PMD already re-configures the port. > >>>>>>>>> + The application should restore some additional configuration, > >>>>>>>>> and then > >>>>>>>>> + enable data path API invocation. > >>>>>>>>> > >>>>>>>>> ``RTE_ETH_EVENT_RECOVERY_FAILED`` > >>>>>>>>> Notify the application that the recovery from error failed, > >>>>>>>>> diff --git a/lib/ethdev/ethdev_driver.c b/lib/ethdev/ethdev_driver.c > >>>>>>>>> index 0be1e8ca04..f994653fe9 100644 > >>>>>>>>> --- a/lib/ethdev/ethdev_driver.c > >>>>>>>>> +++ b/lib/ethdev/ethdev_driver.c > >>>>>>>>> @@ -515,6 +515,14 @@ rte_eth_dma_zone_free(const struct rte_eth_dev > >>>>>>>>> *dev, const char *ring_name, > >>>>>>>>> return rc; > >>>>>>>>> } > >>>>>>>>> > >>>>>>>>> +void > >>>>>>>>> +rte_eth_fp_ops_setup(struct rte_eth_dev *dev) > >>>>>>>>> +{ > >>>>>>>>> + if (dev == NULL) > >>>>>>>>> + return; > >>>>>>>>> + eth_dev_fp_ops_setup(rte_eth_fp_ops + dev->data->port_id, dev); > >>>>>>>>> +} > >>>>>>>>> + > >>>>>>>>> const struct rte_memzone * > >>>>>>>>> rte_eth_dma_zone_reserve(const struct rte_eth_dev *dev, const char > >>>>>>>>> *ring_name, > >>>>>>>>> uint16_t queue_id, size_t size, unsigned int align, > >>>>>>>>> diff --git a/lib/ethdev/ethdev_driver.h b/lib/ethdev/ethdev_driver.h > >>>>>>>>> index 2c9d615fb5..0d964d1f67 100644 > >>>>>>>>> --- a/lib/ethdev/ethdev_driver.h > >>>>>>>>> +++ b/lib/ethdev/ethdev_driver.h > >>>>>>>>> @@ -1621,6 +1621,16 @@ int > >>>>>>>>> rte_eth_dma_zone_free(const struct rte_eth_dev *eth_dev, const > >>>>>>>>> char *name, > >>>>>>>>> uint16_t queue_id); > >>>>>>>>> > >>>>>>>>> +/** > >>>>>>>>> + * @internal > >>>>>>>>> + * Setup eth fast-path API to ethdev values. > >>>>>>>>> + * > >>>>>>>>> + * @param dev > >>>>>>>>> + * Pointer to struct rte_eth_dev. > >>>>>>>>> + */ > >>>>>>>>> +__rte_internal > >>>>>>>>> +void rte_eth_fp_ops_setup(struct rte_eth_dev *dev); > >>>>>>>>> + > >>>>>>>>> /** > >>>>>>>>> * @internal > >>>>>>>>> * Atomically set the link status for the specific device. > >>>>>>>>> diff --git a/lib/ethdev/rte_ethdev.h b/lib/ethdev/rte_ethdev.h > >>>>>>>>> index 049641d57c..44ee7229c1 100644 > >>>>>>>>> --- a/lib/ethdev/rte_ethdev.h > >>>>>>>>> +++ b/lib/ethdev/rte_ethdev.h > >>>>>>>>> @@ -3944,25 +3944,28 @@ enum rte_eth_event_type { > >>>>>>>>> */ > >>>>>>>>> RTE_ETH_EVENT_RX_AVAIL_THRESH, > >>>>>>>>> /** Port recovering from a hardware or firmware error. > >>>>>>>>> - * If PMD supports proactive error recovery, > >>>>>>>>> - * it should trigger this event to notify application > >>>>>>>>> - * that it detected an error and the recovery is being started. > >>>>>>>>> - * Upon receiving the event, the application should not invoke > >>>>>>>>> any control path API > >>>>>>>>> - * (such as rte_eth_dev_configure/rte_eth_dev_stop...) until > >>>>>>>>> receiving > >>>>>>>>> - * RTE_ETH_EVENT_RECOVERY_SUCCESS or > >>>>>>>>> RTE_ETH_EVENT_RECOVERY_FAILED event. > >>>>>>>>> - * The PMD will set the data path pointers to dummy functions, > >>>>>>>>> - * and re-set the data path pointers to non-dummy functions > >>>>>>>>> - * before reporting RTE_ETH_EVENT_RECOVERY_SUCCESS event. > >>>>>>>>> - * It means that the application cannot send or receive any > >>>>>>>>> packets > >>>>>>>>> - * during this period. > >>>>>>>>> + * > >>>>>>>>> + * If PMD supports proactive error recovery, it should trigger > >>>>>>>>> this > >>>>>>>>> + * event to notify application that it detected an error and > >>>>>>>>> the > >>>>>>>>> + * recovery is about to start. > >>>>>>>>> + * > >>>>>>>>> + * Upon receiving the event, the application should not invoke > >>>>>>>>> any > >>>>>>>>> + * control and data path API until receiving > >>>>>>>>> + * RTE_ETH_EVENT_RECOVERY_SUCCESS or > >>>>>>>>> RTE_ETH_EVENT_RECOVERY_FAILED > >>>>>>>>> + * event. > >>>>>>>>> + * > >>>>>>>>> + * Once this event is reported, the PMD will set the data path > >>>>>>>>> pointers > >>>>>>>>> + * to dummy functions, and re-set the data path pointers to > >>>>>>>>> valid > >>>>>>>>> + * functions before reporting RTE_ETH_EVENT_RECOVERY_SUCCESS > >>>>>>>>> event. > >>>>>>>>> + * > >>>>>>>>> * @note Before the PMD reports the recovery result, > >>>>>>>>> * the PMD may report the RTE_ETH_EVENT_ERR_RECOVERING event > >>>>>>>>> again, > >>>>>>>>> * because a larger error may occur during the recovery. > >>>>>>>>> */ > >>>>>>>>> RTE_ETH_EVENT_ERR_RECOVERING, > >>>>>>>>> /** Port recovers successfully from the error. > >>>>>>>>> - * The PMD already re-configured the port, > >>>>>>>>> - * and the effect is the same as a restart operation. > >>>>>>>>> + * > >>>>>>>>> + * The PMD already re-configured the port: > >>>>>>>>> * a) The following operation will be retained: > >>>>>>>>> (alphabetically) > >>>>>>>>> * - DCB configuration > >>>>>>>>> * - FEC configuration > >>>>>>>>> @@ -3989,6 +3992,9 @@ enum rte_eth_event_type { > >>>>>>>>> * (@see RTE_ETH_DEV_CAPA_FLOW_SHARED_OBJECT_KEEP) > >>>>>>>>> * c) Any other configuration will not be stored > >>>>>>>>> * and will need to be re-configured. > >>>>>>>>> + * > >>>>>>>>> + * The application should restore some additional configuration > >>>>>>>>> + * (see above case b/c), and then enable data path API > >>>>>>>>> invocation. > >>>>>>>>> */ > >>>>>>>>> RTE_ETH_EVENT_RECOVERY_SUCCESS, > >>>>>>>>> /** Port recovery failed. > >>>>>>>>> diff --git a/lib/ethdev/version.map b/lib/ethdev/version.map > >>>>>>>>> index 357d1a88c0..c273e0bdae 100644 > >>>>>>>>> --- a/lib/ethdev/version.map > >>>>>>>>> +++ b/lib/ethdev/version.map > >>>>>>>>> @@ -320,6 +320,7 @@ INTERNAL { > >>>>>>>>> rte_eth_devices; > >>>>>>>>> rte_eth_dma_zone_free; > >>>>>>>>> rte_eth_dma_zone_reserve; > >>>>>>>>> + rte_eth_fp_ops_setup; > >>>>>>>>> rte_eth_hairpin_queue_peer_bind; > >>>>>>>>> rte_eth_hairpin_queue_peer_unbind; > >>>>>>>>> rte_eth_hairpin_queue_peer_update; > >>>>>>>>> -- > >>>>>>>> Acked-by: Konstantin Ananyev <konstantin.anan...@huawei.com> > >>>>>>>> > >>>>>>>>> 2.17.1 > >>>>>>>> > >>>>>>> > >>>>>> > >>>> > >>>
