Thread (28 messages) 28 messages, 6 authors, 2019-02-11
STALE2700d REVIEWED: 1 (0M)

[PATCH v4 net-next 03/11] devlink: Add health report functionality

From: Eran Ben Elisha <hidden>
Date: 2019-02-07 09:37:04
Subsystem: devlink, networking [general], the rest, tracing · Maintainers: Jiri Pirko, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds, Steven Rostedt, Masami Hiramatsu

Upon error discover, every driver can report it to the devlink health
mechanism via devlink_health_report function, using the appropriate
reporter registered to it. Driver can pass error specific context which
will be delivered to it as part of the dump / recovery callbacks.

Once an error is reported, devlink health will do the following actions:
* A log is being send to the kernel trace events buffer
* Health status and statistics are being updated for the reporter instance
* Object dump is being taken and stored at the reporter instance (as long
  as there is no other dump which is already stored)
* Auto recovery attempt is being done. Depends on:
  - Auto Recovery configuration
  - Grace period vs. Time since last recover

Signed-off-by: Eran Ben Elisha <redacted>
Reviewed-by: Moshe Shemesh <redacted>
---
 include/net/devlink.h          |   9 +++
 include/trace/events/devlink.h |  65 ++++++++++++++++++
 net/core/devlink.c             | 119 +++++++++++++++++++++++++++++++++
 3 files changed, 193 insertions(+)
diff --git a/include/net/devlink.h b/include/net/devlink.h
index 3dfe30235878..c12ad6e9095d 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -704,6 +704,8 @@ devlink_health_reporter_destroy(struct devlink_health_reporter *reporter);
 
 void *
 devlink_health_reporter_priv(struct devlink_health_reporter *reporter);
+int devlink_health_report(struct devlink_health_reporter *reporter,
+			  const char *msg, void *priv_ctx);
 
 #else
 
@@ -1173,6 +1175,13 @@ devlink_health_reporter_priv(struct devlink_health_reporter *reporter)
 {
 	return NULL;
 }
+
+static inline int
+devlink_health_report(struct devlink_health_reporter *reporter,
+		      const char *msg, void *priv_ctx)
+{
+	return 0;
+}
 #endif
 
 #if IS_REACHABLE(CONFIG_NET_DEVLINK)
diff --git a/include/trace/events/devlink.h b/include/trace/events/devlink.h
index 40705364a50f..191ddf67d769 100644
--- a/include/trace/events/devlink.h
+++ b/include/trace/events/devlink.h
@@ -75,6 +75,71 @@ TRACE_EVENT(devlink_hwerr,
 			__get_str(driver_name), __entry->err, __get_str(msg))
 );
 
+/*
+ * Tracepoint for devlink health message:
+ */
+TRACE_EVENT(devlink_health_report,
+	TP_PROTO(const struct devlink *devlink, const char *reporter_name,
+		 const char *msg),
+
+	TP_ARGS(devlink, reporter_name, msg),
+
+	TP_STRUCT__entry(
+		__string(bus_name, devlink->dev->bus->name)
+		__string(dev_name, dev_name(devlink->dev))
+		__string(driver_name, devlink->dev->driver->name)
+		__string(reporter_name, msg)
+		__string(msg, msg)
+	),
+
+	TP_fast_assign(
+		__assign_str(bus_name, devlink->dev->bus->name);
+		__assign_str(dev_name, dev_name(devlink->dev));
+		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(reporter_name, reporter_name);
+		__assign_str(msg, msg);
+	),
+
+	TP_printk("bus_name=%s dev_name=%s driver_name=%s reporter_name=%s: %s",
+		  __get_str(bus_name), __get_str(dev_name),
+		  __get_str(driver_name), __get_str(reporter_name),
+		  __get_str(msg))
+);
+
+/*
+ * Tracepoint for devlink health recover aborted message:
+ */
+TRACE_EVENT(devlink_health_recover_aborted,
+	TP_PROTO(const struct devlink *devlink, const char *reporter_name,
+		 bool health_state, u64 time_since_last_recover),
+
+	TP_ARGS(devlink, reporter_name, health_state, time_since_last_recover),
+
+	TP_STRUCT__entry(
+		__string(bus_name, devlink->dev->bus->name)
+		__string(dev_name, dev_name(devlink->dev))
+		__string(driver_name, devlink->dev->driver->name)
+		__string(reporter_name, reporter_name)
+		__field(bool, health_state)
+		__field(u64, time_since_last_recover)
+	),
+
+	TP_fast_assign(
+		__assign_str(bus_name, devlink->dev->bus->name);
+		__assign_str(dev_name, dev_name(devlink->dev));
+		__assign_str(driver_name, devlink->dev->driver->name);
+		__assign_str(reporter_name, reporter_name);
+		__entry->health_state = health_state;
+		__entry->time_since_last_recover = time_since_last_recover;
+	),
+
+	TP_printk("bus_name=%s dev_name=%s driver_name=%s reporter_name=%s: health_state=%d time_since_last_recover=%llu recover aborted",
+		  __get_str(bus_name), __get_str(dev_name),
+		  __get_str(driver_name), __get_str(reporter_name),
+		  __entry->health_state,
+		  __entry->time_since_last_recover)
+);
+
 #endif /* _TRACE_DEVLINK_H */
 
 /* This part must be outside protection */
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 341548d7f1f1..3eaa290831aa 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -4367,9 +4367,20 @@ struct devlink_health_reporter {
 	void *priv;
 	const struct devlink_health_reporter_ops *ops;
 	struct devlink *devlink;
+	struct devlink_fmsg *dump_fmsg;
+	struct mutex dump_lock; /* lock parallel read/write from dump buffers */
 	u64 graceful_period;
 	bool auto_recover;
 	u8 health_state;
+	u64 dump_ts;
+	u64 error_count;
+	u64 recovery_count;
+	u64 last_recovery_ts;
+};
+
+enum devlink_health_reporter_state {
+	DEVLINK_HEALTH_REPORTER_STATE_HEALTHY,
+	DEVLINK_HEALTH_REPORTER_STATE_ERROR,
 };
 
 void *
@@ -4431,6 +4442,7 @@ devlink_health_reporter_create(struct devlink *devlink,
 	reporter->devlink = devlink;
 	reporter->graceful_period = graceful_period;
 	reporter->auto_recover = auto_recover;
+	mutex_init(&reporter->dump_lock);
 	list_add_tail(&reporter->list, &devlink->reporter_list);
 unlock:
 	mutex_unlock(&devlink->lock);
@@ -4449,10 +4461,117 @@ devlink_health_reporter_destroy(struct devlink_health_reporter *reporter)
 	mutex_lock(&reporter->devlink->lock);
 	list_del(&reporter->list);
 	mutex_unlock(&reporter->devlink->lock);
+	if (reporter->dump_fmsg)
+		devlink_fmsg_free(reporter->dump_fmsg);
 	kfree(reporter);
 }
 EXPORT_SYMBOL_GPL(devlink_health_reporter_destroy);
 
+static int
+devlink_health_reporter_recover(struct devlink_health_reporter *reporter,
+				void *priv_ctx)
+{
+	int err;
+
+	if (!reporter->ops->recover)
+		return -EOPNOTSUPP;
+
+	err = reporter->ops->recover(reporter, priv_ctx);
+	if (err)
+		return err;
+
+	reporter->recovery_count++;
+	reporter->health_state = DEVLINK_HEALTH_REPORTER_STATE_HEALTHY;
+	reporter->last_recovery_ts = jiffies;
+
+	return 0;
+}
+
+static void
+devlink_health_dump_clear(struct devlink_health_reporter *reporter)
+{
+	if (!reporter->dump_fmsg)
+		return;
+	devlink_fmsg_free(reporter->dump_fmsg);
+	reporter->dump_fmsg = NULL;
+}
+
+static int devlink_health_do_dump(struct devlink_health_reporter *reporter,
+				  void *priv_ctx)
+{
+	int err;
+
+	if (!reporter->ops->dump)
+		return 0;
+
+	if (reporter->dump_fmsg)
+		return 0;
+
+	reporter->dump_fmsg = devlink_fmsg_alloc();
+	if (!reporter->dump_fmsg) {
+		err = -ENOMEM;
+		return err;
+	}
+
+	err = devlink_fmsg_obj_nest_start(reporter->dump_fmsg);
+	if (err)
+		goto dump_err;
+
+	err = reporter->ops->dump(reporter, reporter->dump_fmsg,
+				  priv_ctx);
+	if (err)
+		goto dump_err;
+
+	err = devlink_fmsg_obj_nest_end(reporter->dump_fmsg);
+	if (err)
+		goto dump_err;
+
+	reporter->dump_ts = jiffies;
+
+	return 0;
+
+dump_err:
+	devlink_health_dump_clear(reporter);
+	return err;
+}
+
+int devlink_health_report(struct devlink_health_reporter *reporter,
+			  const char *msg, void *priv_ctx)
+{
+	struct devlink *devlink = reporter->devlink;
+
+	/* write a log message of the current error */
+	WARN_ON(!msg);
+	trace_devlink_health_report(devlink, reporter->ops->name, msg);
+	reporter->error_count++;
+
+	/* abort if the previous error wasn't recovered */
+	if (reporter->auto_recover &&
+	    (reporter->health_state != DEVLINK_HEALTH_REPORTER_STATE_HEALTHY ||
+	     jiffies - reporter->last_recovery_ts <
+	     msecs_to_jiffies(reporter->graceful_period))) {
+		trace_devlink_health_recover_aborted(devlink,
+						     reporter->ops->name,
+						     reporter->health_state,
+						     jiffies -
+						     reporter->last_recovery_ts);
+		return -ECANCELED;
+	}
+
+	reporter->health_state = DEVLINK_HEALTH_REPORTER_STATE_ERROR;
+
+	mutex_lock(&reporter->dump_lock);
+	/* store current dump of current error, for later analysis */
+	devlink_health_do_dump(reporter, priv_ctx);
+	mutex_unlock(&reporter->dump_lock);
+
+	if (reporter->auto_recover)
+		return devlink_health_reporter_recover(reporter, priv_ctx);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devlink_health_report);
+
 static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING },
 	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING },
-- 
2.17.1
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