From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by dpdk.org (Postfix) with ESMTP id 9E4971BAF3 for ; Wed, 11 Apr 2018 13:50:24 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Apr 2018 04:50:23 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,436,1517904000"; d="scan'208";a="36349871" Received: from jguo15x-mobl3.ccr.corp.intel.com (HELO [10.254.215.165]) ([10.254.215.165]) by fmsmga002.fm.intel.com with ESMTP; 11 Apr 2018 04:50:21 -0700 To: "Zhang, Qi Z" , "stephen@networkplumber.org" , "Richardson, Bruce" , "Yigit, Ferruh" , "Ananyev, Konstantin" , "gaetan.rivet@6wind.com" , "Wu, Jingjing" , "thomas@monjalon.net" , "motih@mellanox.com" , "Van Haaren, Harry" , "Tan, Jianfeng" References: <1522779443-1932-6-git-send-email-jia.guo@intel.com> <1523012217-31146-1-git-send-email-jia.guo@intel.com> <1523012217-31146-3-git-send-email-jia.guo@intel.com> <039ED4275CED7440929022BC67E706115318373C@SHSMSX103.ccr.corp.intel.com> <039ED4275CED7440929022BC67E7061153183785@SHSMSX103.ccr.corp.intel.com> Cc: "jblunck@infradead.org" , "shreyansh.jain@nxp.com" , "dev@dpdk.org" , "Zhang, Helin" From: "Guo, Jia" Message-ID: <1d186fe3-05cf-ac8f-7fba-2ba086993f67@intel.com> Date: Wed, 11 Apr 2018 19:50:20 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <039ED4275CED7440929022BC67E7061153183785@SHSMSX103.ccr.corp.intel.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH V19 2/4] eal: add failure handler mechanism for hot plug 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, 11 Apr 2018 11:50:25 -0000 On 4/6/2018 10:24 PM, Zhang, Qi Z wrote: > One more comment > >> -----Original Message----- >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Zhang, Qi Z >> Sent: Friday, April 6, 2018 10:04 PM >> To: Guo, Jia ; stephen@networkplumber.org; Richardson, >> Bruce ; Yigit, Ferruh ; >> Ananyev, Konstantin ; >> gaetan.rivet@6wind.com; Wu, Jingjing ; >> thomas@monjalon.net; motih@mellanox.com; Van Haaren, Harry >> ; Tan, Jianfeng >> Cc: jblunck@infradead.org; shreyansh.jain@nxp.com; dev@dpdk.org; Guo, Jia >> ; Zhang, Helin >> Subject: Re: [dpdk-dev] [PATCH V19 2/4] eal: add failure handler mechanism >> for hot plug >> >> Hi Jeff: >> >>> -----Original Message----- >>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Jeff Guo >>> Sent: Friday, April 6, 2018 6:57 PM >>> To: stephen@networkplumber.org; Richardson, Bruce >>> ; Yigit, Ferruh ; >>> Ananyev, Konstantin ; >>> gaetan.rivet@6wind.com; Wu, Jingjing ; >>> thomas@monjalon.net; motih@mellanox.com; Van Haaren, Harry >>> ; Tan, Jianfeng >>> Cc: jblunck@infradead.org; shreyansh.jain@nxp.com; dev@dpdk.org; Guo, >>> Jia ; Zhang, Helin >>> Subject: [dpdk-dev] [PATCH V19 2/4] eal: add failure handler mechanism >>> for hot plug >>> >>> This patch introduces an API (rte_dev_handle_hot_unplug) to handle >>> device hot unplug event. When device be hot plug out, the device >>> resource become invalid, if this resource is still be unexpected >>> read/write, system will crash. The api let user register the hot >>> unplug handler, > The description is a little bit misleading , based on current implementation. > it does not a function that let user "register a handler", actually It let user to > "set a recover point" when some exception (like sigbus) happen due to hot unplug. > Maybe the function name could be changed also, > for example: rte_dev_set_recover_point. make sense , will check the better way demonstrate that. >> when hot plug failure occur, the working thread will >>> be block until the uevent mechanism successful recovery the memory and >> guaranty the application keep running smoothly. >>> Signed-off-by: Jeff Guo >>> --- >>> v19->18: >>> add note for limitation of multiple hotplug >>> --- >>> doc/guides/rel_notes/release_18_05.rst | 6 ++ >>> kernel/linux/igb_uio/igb_uio.c | 4 + >>> lib/librte_eal/common/include/rte_dev.h | 19 +++++ >>> lib/librte_eal/linuxapp/eal/eal_dev.c | 140 >>> +++++++++++++++++++++++++++++++- >>> lib/librte_eal/rte_eal_version.map | 1 + >>> 5 files changed, 169 insertions(+), 1 deletion(-) >>> >>> diff --git a/doc/guides/rel_notes/release_18_05.rst >>> b/doc/guides/rel_notes/release_18_05.rst >>> index cb9e050..2707e73 100644 >>> --- a/doc/guides/rel_notes/release_18_05.rst >>> +++ b/doc/guides/rel_notes/release_18_05.rst >>> @@ -70,6 +70,12 @@ New Features >>> >>> Linux uevent is supported as backend of this device event >>> notification framework. >>> >>> +* **Added hot plug failure handler.** >>> + >>> + Added a failure handler machenism to handle hot unplug device. >>> + >>> + * ``rte_dev_handle_hot_unplug`` for handle hot unplug device failure. >>> + >>> API Changes >>> ----------- >>> >>> diff --git a/kernel/linux/igb_uio/igb_uio.c >>> b/kernel/linux/igb_uio/igb_uio.c index 4cae4dd..293c310 100644 >>> --- a/kernel/linux/igb_uio/igb_uio.c >>> +++ b/kernel/linux/igb_uio/igb_uio.c >>> @@ -344,6 +344,10 @@ igbuio_pci_release(struct uio_info *info, struct >>> inode >>> *inode) >>> struct rte_uio_pci_dev *udev = info->priv; >>> struct pci_dev *dev = udev->pdev; >>> >>> + /* check if device has been remove before release */ >>> + if ((&dev->dev.kobj)->state_remove_uevent_sent == 1) >>> + return -1; >>> + >>> mutex_lock(&udev->lock); >>> if (--udev->refcnt > 0) { >>> mutex_unlock(&udev->lock); >>> diff --git a/lib/librte_eal/common/include/rte_dev.h >>> b/lib/librte_eal/common/include/rte_dev.h >>> index a5203e7..17c446d 100644 >>> --- a/lib/librte_eal/common/include/rte_dev.h >>> +++ b/lib/librte_eal/common/include/rte_dev.h >>> @@ -361,4 +361,23 @@ rte_dev_event_monitor_start(void); >>> */ >>> int __rte_experimental >>> rte_dev_event_monitor_stop(void); >>> + >>> +/** >>> + * @warning >>> + * @b EXPERIMENTAL: this API may change without prior notice >>> + * >>> + * It can be used to register the device signal bus handler, and save >>> +the >>> + * current environment for each thread, when signal bus error invoke, >>> +the >>> + * handler would restore the environment by long jmp to each working >>> + * thread previous locate, then block the thread to waiting until the >>> +memory >>> + * recovery and remapping be finished, that would guaranty the system >>> +not >>> + * crash when the device be hot unplug. >>> + * >>> + * @param none >>> + * @return >>> + * - From a successful direct invocation, zero. >>> + * - From a call of siglongjmp(), non_zero. >>> + */ >>> +int __rte_experimental >>> +rte_dev_handle_hot_unplug(void); >>> #endif /* _RTE_DEV_H_ */ >>> diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c >>> b/lib/librte_eal/linuxapp/eal/eal_dev.c >>> index 9478a39..84b7efc 100644 >>> --- a/lib/librte_eal/linuxapp/eal/eal_dev.c >>> +++ b/lib/librte_eal/linuxapp/eal/eal_dev.c >>> @@ -4,6 +4,9 @@ >>> >>> #include >>> #include >>> +#include >>> +#include >>> +#include >>> #include >>> #include >>> >>> @@ -13,12 +16,17 @@ >>> #include >>> #include >>> #include >>> +#include >>> +#include >>> >>> #include "eal_private.h" >>> >>> static struct rte_intr_handle intr_handle = {.fd = -1 }; static bool >>> monitor_started; >>> >>> +pthread_mutex_t failure_recovery_lock; pthread_cond_t >>> +failure_recovery_cond; >>> + >>> #define EAL_UEV_MSG_LEN 4096 >>> #define EAL_UEV_MSG_ELEM_LEN 128 >>> >>> @@ -32,6 +40,22 @@ enum eal_dev_event_subsystem { >>> EAL_DEV_EVENT_SUBSYSTEM_MAX >>> }; >>> >>> +static RTE_DEFINE_PER_LCORE(sigjmp_buf, unplug_longjmp_env); >>> + >>> +static void sigbus_handler(int signum __rte_unused) { >>> + RTE_LOG(DEBUG, EAL, "receive SIGBUS error!\n"); >>> + siglongjmp(RTE_PER_LCORE(unplug_longjmp_env), 1); } >>> + >>> +static int cmp_dev_name(const struct rte_device *dev, >>> + const void *_name) >>> +{ >>> + const char *name = _name; >>> + >>> + return strcmp(dev->name, name); >>> +} >>> + >>> static int >>> dev_uev_socket_fd_create(void) >>> { >>> @@ -132,6 +156,31 @@ dev_uev_parse(const char *buf, struct >>> rte_dev_event *event, int length) >>> return 0; >>> } >>> >>> +static int >>> +dev_uev_remove_handler(struct rte_device *dev) { >>> + struct rte_bus *bus = rte_bus_find_by_device_name(dev->name); >>> + int ret; >>> + >>> + if (!dev) >>> + return -1; >>> + >>> + if (bus->handle_hot_unplug) { >>> + /** >>> + * call bus ops to handle hot unplug. >>> + */ >>> + ret = bus->handle_hot_unplug(dev); >>> + if (ret) { >>> + RTE_LOG(ERR, EAL, >>> + "It cannot handle hot unplug for device (%s) " >>> + "on the bus.\n ", >>> + dev->name); >>> + return ret; >>> + } >>> + } >>> + return 0; >>> +} >>> + >>> static void >>> dev_delayed_unregister(void *param) >>> { >>> @@ -146,6 +195,9 @@ dev_uev_handler(__rte_unused void *param) >>> struct rte_dev_event uevent; >>> int ret; >>> char buf[EAL_UEV_MSG_LEN]; >>> + struct rte_bus *bus; >>> + struct rte_device *dev; >>> + const char *busname; >>> >>> memset(&uevent, 0, sizeof(struct rte_dev_event)); >>> memset(buf, 0, EAL_UEV_MSG_LEN); >>> @@ -170,11 +222,87 @@ dev_uev_handler(__rte_unused void *param) >>> RTE_LOG(DEBUG, EAL, "receive uevent(name:%s, type:%d, >>> subsystem:%d)\n", >>> uevent.devname, uevent.type, uevent.subsystem); >>> >>> - if (uevent.devname) >>> + switch (uevent.subsystem) { >>> + case EAL_DEV_EVENT_SUBSYSTEM_PCI: >>> + case EAL_DEV_EVENT_SUBSYSTEM_UIO: >>> + busname = "pci"; >>> + break; >>> + default: >>> + break; >>> + } >>> + >>> + if (uevent.devname) { >>> + if (uevent.type == RTE_DEV_EVENT_REMOVE) { >>> + bus = rte_bus_find_by_name(busname); >>> + if (bus == NULL) { >>> + RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n", >>> + uevent.devname); >>> + return; >>> + } >>> + dev = bus->find_device(NULL, cmp_dev_name, >>> + uevent.devname); >>> + if (dev == NULL) { >>> + RTE_LOG(ERR, EAL, >>> + "Cannot find unplugged device (%s)\n", >>> + uevent.devname); >>> + return; >>> + } >>> + ret = dev_uev_remove_handler(dev); >>> + if (ret) { >>> + RTE_LOG(ERR, EAL, "Driver cannot remap the " >>> + "device (%s)\n", >>> + dev->name); >>> + return; >>> + } >>> + /* wake up all the threads */ >>> + pthread_cond_broadcast(&failure_recovery_cond); >>> + } >>> dev_callback_process(uevent.devname, uevent.type); >>> + } >>> } >>> >>> int __rte_experimental >>> +rte_dev_handle_hot_unplug(void) >>> +{ >>> + struct sigaction act; >>> + sigset_t mask; >>> + int ret = 0; >>> + >>> + /* set signal handlers */ >>> + memset(&act, 0x00, sizeof(struct sigaction)); >>> + act.sa_handler = sigbus_handler; >>> + sigemptyset(&act.sa_mask); >>> + act.sa_flags = SA_RESTART; >>> + sigaction(SIGBUS, &act, NULL); >>> + sigemptyset(&mask); >>> + sigaddset(&mask, SIGBUS); >>> + pthread_sigmask(SIG_UNBLOCK, &mask, NULL); >>> + >>> + ret = sigsetjmp(RTE_PER_LCORE(unplug_longjmp_env), 1); >>> + if (ret) { >>> + /* >>> + * Waitting for condition variable before failure recovery >>> + * finish. Now the limitation is only handle one device >>> + * hot plug, for multiple devices hotplug, need check if >>> + * the device belong to this working thread, then directly >>> + * call memory remaping, unrelated thread just keep going >>> + * their work by no interrupt from hotplug. >>> + * TODO: multiple device hotplug >>> + */ >>> + pthread_mutex_lock(&failure_recovery_lock); >>> + RTE_LOG(DEBUG, EAL, "begin waiting for the failure handler.\n"); >>> + pthread_cond_wait(&failure_recovery_cond, >>> + &failure_recovery_lock); >>> + RTE_LOG(DEBUG, EAL, >>> + "come back from waiting for failure handler.\n"); >>> + pthread_mutex_unlock(&failure_recovery_lock); >> I think we should not assume phread_cond_wait always happen before >> pthread_cond_broadcast, It is possible Sigbus just happen before remap in >> udev remove handler while pthread_cond_wait happens after >> pthread_cond_broadcast, then we will wait forever. >> >> I think we need a flag to sync >> For example: >> >> pthread_mutex_lock(&failure_recovery_lock); >> if ( udev_remove_handle == 0 ) >> pthread_cond_wait(&failure_recovery_cond, & failure_recovery_lock); >> pthread_remove_handle = 0; pthread_mutex_unlock(&failure_recovery_lock); >> >> while at remove handler: >> pthread_mutex_lock(&failure_recovery_lock); >> pthread_remove_handle = 1; >> pthread_cond_signel(&failure_recovery_cond); >> pthread_mutex_unlock(&failure_recovery_lock); >> >> >> Regards >> Qi >> >>> + } >>> + >>> + return ret; >>> +} >>> + >>> + >>> +int __rte_experimental >>> rte_dev_event_monitor_start(void) >>> { >>> int ret; >>> @@ -196,6 +324,12 @@ rte_dev_event_monitor_start(void) >>> return -1; >>> } >>> >>> + /* initialize mutex and condition variable >>> + * to control failure recovery. >>> + */ >>> + pthread_mutex_init(&failure_recovery_lock, NULL); >>> + pthread_cond_init(&failure_recovery_cond, NULL); >>> + >>> monitor_started = true; >>> >>> return 0; >>> @@ -219,5 +353,9 @@ rte_dev_event_monitor_stop(void) >>> close(intr_handle.fd); >>> intr_handle.fd = -1; >>> monitor_started = false; >>> + >>> + pthread_cond_destroy(&failure_recovery_cond); >>> + pthread_mutex_destroy(&failure_recovery_lock); >>> + >>> return 0; >>> } >>> diff --git a/lib/librte_eal/rte_eal_version.map >>> b/lib/librte_eal/rte_eal_version.map >>> index fc5c62a..873ef38 100644 >>> --- a/lib/librte_eal/rte_eal_version.map >>> +++ b/lib/librte_eal/rte_eal_version.map >>> @@ -262,5 +262,6 @@ EXPERIMENTAL { >>> rte_dev_event_monitor_stop; >>> rte_dev_event_callback_register; >>> rte_dev_event_callback_unregister; >>> + rte_dev_handle_hot_unplug; >>> >>> } DPDK_18.02; >>> -- >>> 2.7.4