From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ananyev, Konstantin" Subject: Re: [PATCH V20 2/4] eal: add failure handler mechanism for hot plug Date: Fri, 20 Apr 2018 11:14:49 +0000 Message-ID: <2601191342CEEE43887BDE71AB977258AE918AD6@IRSMSX102.ger.corp.intel.com> References: <1498711073-42917-1-git-send-email-jia.guo@intel.com> <1524058689-4954-1-git-send-email-jia.guo@intel.com> <1524058689-4954-3-git-send-email-jia.guo@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: "jblunck@infradead.org" , "shreyansh.jain@nxp.com" , "dev@dpdk.org" , "Zhang, Helin" To: "Guo, Jia" , "stephen@networkplumber.org" , "Richardson, Bruce" , "Yigit, Ferruh" , "gaetan.rivet@6wind.com" , "Wu, Jingjing" , "thomas@monjalon.net" , "motih@mellanox.com" , "matan@mellanox.com" , "Van Haaren, Harry" , "Tan, Jianfeng" Return-path: Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id 68B978D9D for ; Fri, 20 Apr 2018 13:14:53 +0200 (CEST) In-Reply-To: <1524058689-4954-3-git-send-email-jia.guo@intel.com> Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" > This patch introduces a failure handler mechanism 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. This patch let eal help application to handle > this fault, when sigbus error occur, check the failure address and > accordingly remap the invalid memory for the corresponding device, > that could guaranty the application not to be shut down when hot plug. >=20 > Signed-off-by: Jeff Guo > --- > v20->v19: > refine the logic of remapping for multiple device. > --- > doc/guides/rel_notes/release_18_05.rst | 6 ++ > lib/librte_eal/common/include/rte_dev.h | 11 +++ > lib/librte_eal/linuxapp/eal/eal_dev.c | 124 ++++++++++++++++++++++++++= +++++- > lib/librte_eal/rte_eal_version.map | 1 + > 4 files changed, 141 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 a018ef5..a4ea9af 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. > + >=20 > API Changes > ----------- > diff --git a/lib/librte_eal/common/include/rte_dev.h b/lib/librte_eal/com= mon/include/rte_dev.h > index 0955e9a..9933131 100644 > --- a/lib/librte_eal/common/include/rte_dev.h > +++ b/lib/librte_eal/common/include/rte_dev.h > @@ -360,4 +360,15 @@ rte_dev_event_monitor_start(void); > int __rte_experimental > rte_dev_event_monitor_stop(void); >=20 > +/** > + * @warning > + * @b EXPERIMENTAL: this API may change without prior notice > + * > + * It can be used to handle the device signal bus error. when signal bus= error > + * occur, the handler would check the failure address to find the corres= ponding > + * device and remap the memory resource of the device, that would guaran= ty > + * the system not crash when the device be hot unplug. > + */ > +void __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..33e7026 100644 > --- a/lib/librte_eal/linuxapp/eal/eal_dev.c > +++ b/lib/librte_eal/linuxapp/eal/eal_dev.c > @@ -4,6 +4,8 @@ >=20 > #include > #include > +#include > +#include > #include > #include >=20 > @@ -13,12 +15,16 @@ > #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 > +extern struct rte_bus_list rte_bus_list; > + > #define EAL_UEV_MSG_LEN 4096 > #define EAL_UEV_MSG_ELEM_LEN 128 >=20 > @@ -33,6 +39,68 @@ enum eal_dev_event_subsystem { > }; >=20 > static int > +dev_uev_failure_process(struct rte_device *dev, void *dev_addr) > +{ > + struct rte_bus *bus; > + int ret =3D 0; > + > + if (!dev && !dev_addr) { > + return -EINVAL; > + } else if (dev) { > + bus =3D rte_bus_find_by_device_name(dev->name); > + if (bus->handle_hot_unplug) { > + /** > + * call bus ops to handle hot unplug. > + */ > + ret =3D bus->handle_hot_unplug(dev, dev_addr); > + if (ret) { > + RTE_LOG(ERR, EAL, > + "It cannot handle hot unplug " > + "for device (%s) " > + "on the bus.\n ", > + dev->name); > + } > + } You would retrun 0 if bus->handle_hot_unplug =3D=3D NULL. Is that intended? Shouldn't be I think. > + } else { > + TAILQ_FOREACH(bus, &rte_bus_list, next) { > + if (bus->handle_hot_unplug) { > + /** > + * call bus ops to handle hot unplug. > + */ > + ret =3D bus->handle_hot_unplug(dev, dev_addr); > + if (ret) { > + RTE_LOG(ERR, EAL, > + "It cannot handle hot unplug " > + "for the device " > + "on the bus.\n "); > + } So how we would know what happened here: That address doesn't belong to that bus or unplug_handler failed? Should we separate search and unplug ops? Another question - shouldn't we break out of loop if bus->handle_hot_unplug= () returns 0? Otherwise you can return error value even when unplug handled worked correc= tly. > + } > + } > + } > + return ret; > +} > + > +static void sigbus_handler(int signum __rte_unused, siginfo_t *info, > + void *ctx __rte_unused) > +{ > + int ret; > + > + RTE_LOG(ERR, EAL, "SIGBUS error, fault address:%p\n", info->si_addr); > + ret =3D dev_uev_failure_process(NULL, info->si_addr); As now you can try to mmap/munmap same address from two or more different t= hreads you probably need some synchronization here. Something simple as spinlock seems to be enough here.=20 We might have one per device or might be even a global one would be ok here= . > + if (!ret) > + RTE_LOG(DEBUG, EAL, > + "SIGBUS error is because of hot unplug!\n"); > +} > + > +static int cmp_dev_name(const struct rte_device *dev, > + const void *_name) > +{ > + const char *name =3D _name; > + > + return strcmp(dev->name, name); > +} Is it really worth a separate function? > + > +static int > dev_uev_socket_fd_create(void) > { > struct sockaddr_nl addr; > @@ -146,6 +214,9 @@ 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); > @@ -170,8 +241,41 @@ 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_failure_process(dev, NULL); > + if (ret) { > + RTE_LOG(ERR, EAL, "Driver cannot remap the " > + "device (%s)\n", > + dev->name); > + return; > + } > + } > dev_callback_process(uevent.devname, uevent.type); > + } > } >=20 > int __rte_experimental > @@ -216,8 +320,26 @@ rte_dev_event_monitor_stop(void) > return ret; > } >=20 > + /* recover sigbus. */ > + sigaction(SIGBUS, NULL, NULL); > + Probably better to restore previous action. > close(intr_handle.fd); > intr_handle.fd =3D -1; > monitor_started =3D false; > + > return 0; > } > + > +void __rte_experimental > +rte_dev_handle_hot_unplug(void) > +{ > + struct sigaction act; > + > + /* set sigbus handler for hotplug. */ > + memset(&act, 0x00, sizeof(struct sigaction)); > + act.sa_sigaction =3D sigbus_handler; > + sigemptyset(&act.sa_mask); > + sigaddset(&act.sa_mask, SIGBUS); > + act.sa_flags =3D SA_SIGINFO; > + sigaction(SIGBUS, &act, NULL); > +} > diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_= version.map > index d02d80b..39a0213 100644 > --- a/lib/librte_eal/rte_eal_version.map > +++ b/lib/librte_eal/rte_eal_version.map > @@ -217,6 +217,7 @@ EXPERIMENTAL { > rte_dev_event_callback_unregister; > rte_dev_event_monitor_start; > rte_dev_event_monitor_stop; > + rte_dev_handle_hot_unplug; > rte_eal_cleanup; > rte_eal_devargs_insert; > rte_eal_devargs_parse; > -- > 2.7.4