From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Guo, Jia" Subject: Re: [PATCH V20 2/4] eal: add failure handler mechanism for hot plug Date: Thu, 3 May 2018 11:13:49 +0800 Message-ID: <4c32f88e-d4fa-64a2-50ba-51e038e81430@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> <2601191342CEEE43887BDE71AB977258AE918AD6@IRSMSX102.ger.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Cc: "jblunck@infradead.org" , "shreyansh.jain@nxp.com" , "dev@dpdk.org" , "Zhang, Helin" To: "Ananyev, Konstantin" , "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 mga18.intel.com (mga18.intel.com [134.134.136.126]) by dpdk.org (Postfix) with ESMTP id 4BDC72BAA for ; Thu, 3 May 2018 05:13:53 +0200 (CEST) In-Reply-To: <2601191342CEEE43887BDE71AB977258AE918AD6@IRSMSX102.ger.corp.intel.com> List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 4/20/2018 7:14 PM, Ananyev, Konstantin wrote: > >> 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. >> >> 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(-) >> >> diff --git a/doc/guides/rel_notes/release_18_05.rst b/doc/guides/rel_notes/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 >> >> 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/lib/librte_eal/common/include/rte_dev.h b/lib/librte_eal/common/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); >> >> +/** >> + * @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 corresponding >> + * device and remap the memory resource of the device, that would guaranty >> + * 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/linuxapp/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 @@ >> >> #include >> #include >> +#include >> +#include >> #include >> #include >> >> @@ -13,12 +15,16 @@ >> #include >> #include >> #include >> +#include >> +#include >> >> #include "eal_private.h" >> >> static struct rte_intr_handle intr_handle = {.fd = -1 }; >> static bool monitor_started; >> >> +extern struct rte_bus_list rte_bus_list; >> + >> #define EAL_UEV_MSG_LEN 4096 >> #define EAL_UEV_MSG_ELEM_LEN 128 >> >> @@ -33,6 +39,68 @@ enum eal_dev_event_subsystem { >> }; >> >> static int >> +dev_uev_failure_process(struct rte_device *dev, void *dev_addr) >> +{ >> + struct rte_bus *bus; >> + int ret = 0; >> + >> + if (!dev && !dev_addr) { >> + return -EINVAL; >> + } else if (dev) { >> + bus = rte_bus_find_by_device_name(dev->name); >> + if (bus->handle_hot_unplug) { >> + /** >> + * call bus ops to handle hot unplug. >> + */ >> + ret = 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 == NULL. > Is that intended? > Shouldn't be I think. shouldn't be. will modify it. >> + } else { >> + TAILQ_FOREACH(bus, &rte_bus_list, next) { >> + if (bus->handle_hot_unplug) { >> + /** >> + * call bus ops to handle hot unplug. >> + */ >> + ret = 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 correctly. > you are right here. >> + } >> + } >> + } >> + 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 = dev_uev_failure_process(NULL, info->si_addr); > As now you can try to mmap/munmap same address from two or more different threads > you probably need some synchronization here. > Something simple as spinlock seems to be enough here. > We might have one per device or might be even a global one would be ok here. i think global one and synchronization would be fine. >> + 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 = _name; >> + >> + return strcmp(dev->name, name); >> +} > Is it really worth a separate function? i think that would be the bus ops struct of rte_bus_find_device_t usage here. >> + >> +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; >> >> 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); >> >> - 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_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); >> + } >> } >> >> int __rte_experimental >> @@ -216,8 +320,26 @@ rte_dev_event_monitor_stop(void) >> return ret; >> } >> >> + /* recover sigbus. */ >> + sigaction(SIGBUS, NULL, NULL); >> + > Probably better to restore previous action. correct, restore the previous sigbus action so that no affect other. >> close(intr_handle.fd); >> intr_handle.fd = -1; >> monitor_started = 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 = sigbus_handler; >> + sigemptyset(&act.sa_mask); >> + sigaddset(&act.sa_mask, SIGBUS); >> + act.sa_flags = 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