[dpdk-dev] [PATCH V5 6/7] eal: add failure handle mechanism for hotplug

Jeff Guo jia.guo at intel.com
Mon Jul 9 07:40:11 CEST 2018



On 7/8/2018 9:46 PM, Andrew Rybchenko wrote:
> On 05.07.2018 10:38, Jeff Guo wrote:
>> This patch introduces a failure handler mechanism to handle device
>> hot plug removal event.
>>
>> First register sigbus handler, once sigbus error be captured, will
>> check the failure address and accordingly remap the invalid memory
>> for the corresponding device. Bese on this mechanism, it could
>> guaranty the application not to be crash when hotplug out device.
>>
>> Signed-off-by: Jeff Guo <jia.guo at intel.com>
>> ---
>> v5->v4:
>> add sigbus old handler recover.
>> ---
>>   lib/librte_eal/linuxapp/eal/eal_dev.c | 111 
>> +++++++++++++++++++++++++++++++++-
>>   1 file changed, 110 insertions(+), 1 deletion(-)
>>
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_dev.c 
>> b/lib/librte_eal/linuxapp/eal/eal_dev.c
>> index 1cf6aeb..a22cb9a 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_dev.c
>> +++ b/lib/librte_eal/linuxapp/eal/eal_dev.c
>> @@ -4,6 +4,8 @@
>>     #include <string.h>
>>   #include <unistd.h>
>> +#include <fcntl.h>
>> +#include <signal.h>
>>   #include <sys/socket.h>
>>   #include <linux/netlink.h>
>>   @@ -14,15 +16,28 @@
>>   #include <rte_malloc.h>
>>   #include <rte_interrupts.h>
>>   #include <rte_alarm.h>
>> +#include <rte_bus.h>
>> +#include <rte_eal.h>
>> +#include <rte_spinlock.h>
>> +#include <rte_errno.h>
>>     #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;
>> +
>
> Shouldn't rte_bus.h provide it?
>

I think rte_bus.h provide the rte_bus_list structure,  and then 
announcement a variable in eal_common_bus.c, then i use it by extern in 
eal_dev.c.

>>   #define EAL_UEV_MSG_LEN 4096
>>   #define EAL_UEV_MSG_ELEM_LEN 128
>>   +/* spinlock for device failure process */
>> +static rte_spinlock_t dev_failure_lock = RTE_SPINLOCK_INITIALIZER;
>
> It would be useful to explain why the lock is needed and when
> it should be obtained/released. Which resources are protected
> by the lock?
>

make sense, this locker should be use both bus and device access 
protection. Will explicit to let it to be more readable.

>> +
>> +static struct sigaction sigbus_action_old;
>> +
>> +static int sigbus_need_recover;
>> +
>>   static void dev_uev_handler(__rte_unused void *param);
>>     /* identify the system layer which reports this event. */
>> @@ -33,6 +48,49 @@ enum eal_dev_event_subsystem {
>>       EAL_DEV_EVENT_SUBSYSTEM_MAX
>>   };
>>   +static void
>> +sigbus_action_recover(void)
>> +{
>> +    if (sigbus_need_recover) {
>> +        sigaction(SIGBUS, &sigbus_action_old, NULL);
>> +        sigbus_need_recover = 0;
>> +    }
>> +}
>> +
>> +static void sigbus_handler(int signum, siginfo_t *info,
>> +                void *ctx __rte_unused)
>> +{
>> +    int ret;
>> +
>> +    RTE_LOG(INFO, EAL, "Thread[%d] catch SIGBUS, fault address:%p\n",
>> +        (int)pthread_self(), info->si_addr);
>> +
>> +    rte_spinlock_lock(&dev_failure_lock);
>> +    ret = rte_bus_sigbus_handler(info->si_addr);
>> +    rte_spinlock_unlock(&dev_failure_lock);
>> +    if (ret == -1) {
>> +        rte_exit(EXIT_FAILURE,
>> +             "Failed to handle SIGBUS for hotplug, "
>> +             "(rte_errno: %s)!", strerror(rte_errno));
>> +    } else if (ret == 1) {
>> +        if (sigbus_action_old.sa_handler)
>> +            (*(sigbus_action_old.sa_handler))(signum);
>> +        else
>> +            rte_exit(EXIT_FAILURE,
>> +                 "Failed to handle generic SIGBUS!");
>> +    }
>> +
>> +    RTE_LOG(INFO, EAL, "Success to handle SIGBUS for hotplug!\n");
>> +}
>> +
>> +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)
>>   {
>> @@ -147,6 +205,9 @@ 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);
>> @@ -171,13 +232,50 @@ 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) {
>> +            rte_spinlock_lock(&dev_failure_lock);
>> +            bus = rte_bus_find_by_name(busname);
>
> It looks like busname could be uninitialized here.
>

you are correct i think.

>> +            if (bus == NULL) {
>> +                RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n",
>> +                    busname);
>> +                return;
>> +            }
>> +
>> +            dev = bus->find_device(NULL, cmp_dev_name,
>> +                           uevent.devname);
>> +            if (dev == NULL) {
>> +                RTE_LOG(ERR, EAL, "Cannot find device (%s) on "
>> +                    "bus (%s)\n", uevent.devname, busname);
>> +                return;
>> +            }
>> +
>> +            ret = bus->hotplug_failure_handler(dev);
>> +            rte_spinlock_unlock(&dev_failure_lock);
>> +            if (ret) {
>> +                RTE_LOG(ERR, EAL, "Can not handle hotplug for "
>> +                    "device (%s)\n", dev->name);
>> +                return;
>> +            }
>> +        }
>>           dev_callback_process(uevent.devname, uevent.type);
>> +    }
>>   }
>>     int __rte_experimental
>>   rte_dev_event_monitor_start(void)
>>   {
>> +    sigset_t mask;
>> +    struct sigaction action;
>>       int ret;
>>         if (monitor_started)
>> @@ -197,6 +295,14 @@ rte_dev_event_monitor_start(void)
>>           return -1;
>>       }
>>   +    /* register sigbus handler */
>> +    sigemptyset(&mask);
>> +    sigaddset(&mask, SIGBUS);
>> +    action.sa_flags = SA_SIGINFO;
>> +    action.sa_mask = mask;
>> +    action.sa_sigaction = sigbus_handler;
>> +    sigbus_need_recover = !sigaction(SIGBUS, &action, 
>> &sigbus_action_old);
>> +
>>       monitor_started = true;
>>         return 0;
>> @@ -217,8 +323,11 @@ rte_dev_event_monitor_stop(void)
>>           return ret;
>>       }
>>   +    sigbus_action_recover();
>> +
>>       close(intr_handle.fd);
>>       intr_handle.fd = -1;
>>       monitor_started = false;
>> +
>>       return 0;
>>   }
>



More information about the dev mailing list