[dpdk-dev] [PATCH V21 2/4] eal: add failure handle mechanism for hot plug
Guo, Jia
jia.guo at intel.com
Tue May 8 16:57:21 CEST 2018
On 5/4/2018 11:56 PM, Ananyev, Konstantin wrote:
> Hi Jeff,
>
>> 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 <jia.guo at intel.com>
>> ---
>> v21->v20:
>> sync failure hanlde to fix multiple process issue
>> ---
>> lib/librte_eal/linuxapp/eal/eal_dev.c | 154 +++++++++++++++++++++++++++++++++-
>> 1 file changed, 153 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..3067f39 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 +16,27 @@
>> #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 "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
>>
>> +/* spinlock for device failure process */
>> +static rte_spinlock_t dev_failure_lock = RTE_SPINLOCK_INITIALIZER;
>> +
>> +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. */
>> @@ -34,6 +48,93 @@ 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,
>> + "Cannot handle hot unplug "
>> + "for device %s "
>> + "on the bus %s.\n ",
>> + dev->name, bus->name);
>> + }
>> + } else {
>> + RTE_LOG(ERR, EAL,
>> + "Not support handle hot unplug for bus %s!\n",
>> + bus->name);
>> + ret = -ENOTSUP;
>> + }
>> + } 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,
>> + "Cannot handle hot unplug "
>> + "for the device "
>> + "on the bus %s!\n", bus->name);
>> + else
>> + break;
>> + } else {
>> + RTE_LOG(ERR, EAL,
>> + "Not support handle hot unplug "
>> + "for bus %s!\n", bus->name);
>> + ret = -ENOTSUP;
>> + }
>> + }
>> + }
>> + return ret;
>> +}
>> +
>> +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 __rte_unused, siginfo_t *info,
>> + void *ctx __rte_unused)
>> +{
>> + int ret;
>> +
>> + RTE_LOG(DEBUG, EAL, "Thread[%d] catch SIGBUS, fault address:%p\n",
>> + (int)pthread_self(), info->si_addr);
>> + rte_spinlock_lock(&dev_failure_lock);
>> + ret = dev_uev_failure_process(NULL, info->si_addr);
>> + rte_spinlock_unlock(&dev_failure_lock);
>> + if (!ret)
>> + RTE_LOG(DEBUG, EAL,
>> + "Success to handle SIGBUS error for hot unplug!\n");
>> + else
>> + rte_exit(EXIT_FAILURE, "exit for SIGBUS error!");
> I still think we have to distinguish here 2 cases:
> 1) failure addr is not belong to any dpdk devices
> 2) failure addr does belong to dpdk device, but we fail to remap it.
>
> For 1) we probably need to call previous sigbus handler.
> For 2) we probably can only do exit().
i think the previous sigbus handler is just a exception of sigbus error
and exit out of the process, so i think should use one way to handler
1)+2) should be fine, do you agree with that? or you could find any
chance to
call any other sigbus handler at this positoin?
>> +}
>> +
>> +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)
>> {
>> struct sockaddr_nl addr;
>> @@ -147,6 +248,9 @@ 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 +275,50 @@ 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) {
>> + 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;
>> + }
>> + rte_spinlock_lock(&dev_failure_lock);
>> + ret = dev_uev_failure_process(dev, NULL);
>> + rte_spinlock_unlock(&dev_failure_lock);
> That's interrupt thread, right?
> I wonder could it happen that user will call device_detach() at the same moment?
> Konstantin
it is in interrupt thread, and user will call device_detach after failure process, you concern about twice or more device detach? i don't think is there any problem here.
>> + 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
>> rte_dev_event_monitor_start(void)
>> {
>> + sigset_t mask;
>> + struct sigaction action;
>> int ret;
>>
>> if (monitor_started)
>> @@ -197,6 +338,14 @@ 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 +366,11 @@ rte_dev_event_monitor_stop(void)
>> return ret;
>> }
>>
>> + sigbus_action_recover();
>> +
>> close(intr_handle.fd);
>> intr_handle.fd = -1;
>> monitor_started = false;
>> +
>> return 0;
>> }
>> --
>> 2.7.4
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