> -----Original Message-----
> From: Guo, Jia
> Sent: Tuesday, May 8, 2018 3:57 PM
> To: Ananyev, Konstantin <konstantin.anan...@intel.com>;
> step...@networkplumber.org; Richardson, Bruce
> <bruce.richard...@intel.com>; Yigit, Ferruh <ferruh.yi...@intel.com>;
> gaetan.ri...@6wind.com; Wu, Jingjing
> <jingjing...@intel.com>; tho...@monjalon.net; mo...@mellanox.com;
> ma...@mellanox.com; Van Haaren, Harry
> <harry.van.haa...@intel.com>; Tan, Jianfeng <jianfeng....@intel.com>
> Cc: jblu...@infradead.org; shreyansh.j...@nxp.com; dev@dpdk.org; Zhang, Helin
> <helin.zh...@intel.com>
> Subject: Re: [PATCH V21 2/4] eal: add failure handle mechanism for hot plug
>
>
>
> 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....@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?
I think application can have its own sigbus handler installed (same as we do).
> >> +}
> >> +
> >> +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.
Ok, but user can call device_detach() on his own, without waiting for failure
to happen, right?
>
> >> + 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
