Devlink Health¶
Background¶
The devlink health mechanism is targeted for Real Time Alerting, in
order to know when something bad happened to a PCI device.
- Provide alert debug information.
- Self healing.
- If problem needs vendor support, provide a way to gather all needed debugging information.
Overview¶
The main idea is to unify and centralize driver health reports in the
generic devlink instance and allow the user to set different
attributes of the health reporting and recovery procedures.
The devlink health reporter:
Device driver creates a “health reporter” per each error/health type.
Error/Health type can be a known/generic (eg pci error, fw error, rx/tx error)
or unknown (driver specific).
For each registered health reporter a driver can issue error/health reports
asynchronously. All health reports handling is done by devlink.
Device driver can provide specific callbacks for each “health reporter”, e.g.:
- Recovery procedures
- Diagnostics procedures
- Object dump procedures
- OOB initial parameters
Different parts of the driver can register different types of health reporters with different handlers.
Actions¶
Once an error is reported, devlink health will perform 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 saved 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 passed since last recover
User Interface¶
User can access/change each reporter’s parameters and driver specific callbacks
via devlink, e.g per error type (per health reporter):
- Configure reporter’s generic parameters (like: disable/enable auto recovery)
- Invoke recovery procedure
- Run diagnostics
- Object dump
| Name | Description |
DEVLINK_CMD_HEALTH_REPORTER_GET |
Retrieves status and configuration info per DEV and reporter. |
DEVLINK_CMD_HEALTH_REPORTER_SET |
Allows reporter-related configuration setting. |
DEVLINK_CMD_HEALTH_REPORTER_RECOVER |
Triggers a reporter’s recovery procedure. |
DEVLINK_CMD_HEALTH_REPORTER_DIAGNOSE |
Retrieves diagnostics data from a reporter on a device. |
DEVLINK_CMD_HEALTH_REPORTER_DUMP_GET |
Retrieves the last stored dump. Devlink health saves a single dump. If an dump is not already stored by the devlink for this reporter, devlink generates a new dump. dump output is defined by the reporter. |
DEVLINK_CMD_HEALTH_REPORTER_DUMP_CLEAR |
Clears the last saved dump file for the specified reporter. |
The following diagram provides a general overview of devlink-health:
netlink
+--------------------------+
| |
| + |
| | |
+--------------------------+
|request for ops
|(diagnose,
mlx5_core devlink |recover,
|dump)
+--------+ +--------------------------+
| | | reporter| |
| | | +---------v----------+ |
| | ops execution | | | |
| <----------------------------------+ | |
| | | | | |
| | | + ^------------------+ |
| | | | request for ops |
| | | | (recover, dump) |
| | | | |
| | | +-+------------------+ |
| | health report | | health handler | |
| +-------------------------------> | |
| | | +--------------------+ |
| | health reporter create | |
| +----------------------------> |
+--------+ +--------------------------+