[dpdk-dev] [PATCH V5 6/7] eal: add failure handle mechanism for hotplug
Andrew Rybchenko
arybchenko at solarflare.com
Sun Jul 8 15:46:15 CEST 2018
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?
> #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?
> +
> +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.
> + 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;
> }
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