From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by dpdk.org (Postfix) with ESMTP id BD4291B7F4 for ; Mon, 9 Apr 2018 19:42:42 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Apr 2018 10:42:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.48,427,1517904000"; d="scan'208";a="44752088" Received: from irsmsx107.ger.corp.intel.com ([163.33.3.99]) by fmsmga004.fm.intel.com with ESMTP; 09 Apr 2018 10:42:38 -0700 Received: from irsmsx102.ger.corp.intel.com ([169.254.2.164]) by IRSMSX107.ger.corp.intel.com ([169.254.10.157]) with mapi id 14.03.0319.002; Mon, 9 Apr 2018 18:42:37 +0100 From: "Ananyev, Konstantin" To: "Guo, Jia" , "stephen@networkplumber.org" , "Richardson, Bruce" , "Yigit, Ferruh" , "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" , "Zhang, Helin" Thread-Topic: [PATCH V19 2/4] eal: add failure handler mechanism for hot plug Thread-Index: AQHTzZYx9MpJ9yHxEU2zMfYXi20lBKP4sYYw Date: Mon, 9 Apr 2018 17:42:36 +0000 Message-ID: <2601191342CEEE43887BDE71AB977258AE91267A@IRSMSX102.ger.corp.intel.com> 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> In-Reply-To: <1523012217-31146-3-git-send-email-jia.guo@intel.com> Accept-Language: en-IE, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-titus-metadata-40: eyJDYXRlZ29yeUxhYmVscyI6IiIsIk1ldGFkYXRhIjp7Im5zIjoiaHR0cDpcL1wvd3d3LnRpdHVzLmNvbVwvbnNcL0ludGVsMyIsImlkIjoiY2I1YzljNzItN2M5ZS00NDU0LTg4MzMtNmViMDEyNTg1YzI5IiwicHJvcHMiOlt7Im4iOiJDVFBDbGFzc2lmaWNhdGlvbiIsInZhbHMiOlt7InZhbHVlIjoiQ1RQX05UIn1dfV19LCJTdWJqZWN0TGFiZWxzIjpbXSwiVE1DVmVyc2lvbiI6IjE2LjUuOS4zIiwiVHJ1c3RlZExhYmVsSGFzaCI6Ik92QVdscFRvY2lieXNUczUyM1VZMElpUXlrVXU5VEVBd3FWOEFjaEZEK009In0= x-ctpclassification: CTP_NT dlp-product: dlpe-windows dlp-version: 11.0.200.100 dlp-reaction: no-action x-originating-ip: [163.33.239.182] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 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: Mon, 09 Apr 2018 17:42:43 -0000 Hi Jeff, >=20 > 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 kee= p > running smoothly. >=20 > 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(-) >=20 > diff --git a/doc/guides/rel_notes/release_18_05.rst b/doc/guides/rel_note= s/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 >=20 > Linux uevent is supported as backend of this device event notification= framework. >=20 > +* **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 > ----------- >=20 > diff --git a/kernel/linux/igb_uio/igb_uio.c b/kernel/linux/igb_uio/igb_ui= o.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 ino= de *inode) > struct rte_uio_pci_dev *udev =3D info->priv; > struct pci_dev *dev =3D udev->pdev; >=20 > + /* check if device has been remove before release */ > + if ((&dev->dev.kobj)->state_remove_uevent_sent =3D=3D 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/com= mon/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 th= e > + * current environment for each thread, when signal bus error invoke, th= e > + * handler would restore the environment by long jmp to each working > + * thread previous locate, then block the thread to waiting until the me= mory > + * recovery and remapping be finished, that would guaranty the system no= t > + * 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/linux= app/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 @@ >=20 > #include > #include > +#include > +#include > +#include > #include > #include >=20 > @@ -13,12 +16,17 @@ > #include > #include > #include > +#include > +#include >=20 > #include "eal_private.h" >=20 > static struct rte_intr_handle intr_handle =3D {.fd =3D -1 }; > static bool monitor_started; >=20 > +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 >=20 > @@ -32,6 +40,22 @@ enum eal_dev_event_subsystem { > EAL_DEV_EVENT_SUBSYSTEM_MAX > }; >=20 > +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 =3D _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; > } >=20 > +static int > +dev_uev_remove_handler(struct rte_device *dev) > +{ > + struct rte_bus *bus =3D 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 =3D 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; >=20 > 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); >=20 > - if (uevent.devname) > + switch (uevent.subsystem) { > + case EAL_DEV_EVENT_SUBSYSTEM_PCI: > + case EAL_DEV_EVENT_SUBSYSTEM_UIO: > + busname =3D "pci"; > + break; > + default: > + break; > + } > + > + if (uevent.devname) { > + if (uevent.type =3D=3D RTE_DEV_EVENT_REMOVE) { > + bus =3D rte_bus_find_by_name(busname); > + if (bus =3D=3D NULL) { > + RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n", > + uevent.devname); > + return; > + } > + dev =3D bus->find_device(NULL, cmp_dev_name, > + uevent.devname); > + if (dev =3D=3D NULL) { > + RTE_LOG(ERR, EAL, > + "Cannot find unplugged device (%s)\n", > + uevent.devname); > + return; > + } > + ret =3D 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); > + } > } >=20 > int __rte_experimental > +rte_dev_handle_hot_unplug(void) > +{ > + struct sigaction act; > + sigset_t mask; > + int ret =3D 0; > + > + /* set signal handlers */ > + memset(&act, 0x00, sizeof(struct sigaction)); > + act.sa_handler =3D sigbus_handler; > + sigemptyset(&act.sa_mask); > + act.sa_flags =3D SA_RESTART; > + sigaction(SIGBUS, &act, NULL); > + sigemptyset(&mask); > + sigaddset(&mask, SIGBUS); > + pthread_sigmask(SIG_UNBLOCK, &mask, NULL); Ok, but it is really hard to predict which thread will get a sigbus, even a control thread could be affected just by reading HW stats. Can we make it a unified one, per process? > + > + ret =3D sigsetjmp(RTE_PER_LCORE(unplug_longjmp_env), 1); Hmm... and why we have to do that? Why we can't call recover procedure (as I understand all it will do -=20 mmap our unplugged dev VA to some dummy memory space) from sighandler itsel= f, and then just make thread to resume? > + 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); That's a strange one - how do you know that you received SIGBUS because of = HW unplug? Might be some buggy code is just user tried to access some mmaped file beyo= nd it's boundaries, or so? In that case your signal handler would be hanged forever. Second thing, how do you know that dev_uev_handler() has fixed that particu= lar device unplugging? I think you have first figure out by fault address - is that one of our dev= ice addresses, and if yes - identify which particular. Then do actual remap(). BTW, once again why we need to wipe current prog state with longjmp()? =20 Konstantin > + } > + > + 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; > } >=20 > + /* 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 =3D true; >=20 > return 0; > @@ -219,5 +353,9 @@ rte_dev_event_monitor_stop(void) > close(intr_handle.fd); > intr_handle.fd =3D -1; > monitor_started =3D 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; >=20 > } DPDK_18.02; > -- > 2.7.4