From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id D12D21B718 for ; Wed, 11 Apr 2018 13:49:13 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 11 Apr 2018 04:49:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,436,1517904000"; d="scan'208";a="46039257" Received: from jguo15x-mobl3.ccr.corp.intel.com (HELO [10.254.215.165]) ([10.254.215.165]) by fmsmga001.fm.intel.com with ESMTP; 11 Apr 2018 04:49:10 -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> Cc: "jblunck@infradead.org" , "shreyansh.jain@nxp.com" , "dev@dpdk.org" , "Zhang, Helin" From: "Guo, Jia" Message-ID: <3ad7a446-210b-6fd2-8da3-97c36bba7be8@intel.com> Date: Wed, 11 Apr 2018 19:49:09 +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: <039ED4275CED7440929022BC67E706115318373C@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 11:49:14 -0000 On 4/6/2018 10:03 PM, Zhang, Qi Z wrote: > 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, 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 > make sense, so i think that should be find a better way to handler it, such as use initiative remap to replace of partitive waiting might be better. >> + } >> + >> + 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