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devlink: Add Documentation/networking/devlink-health.txt

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This patch adds a new file to add information about devlink health
mechanism.

Signed-off-by: Aya Levin <ayal@mellanox.com>
Signed-off-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Aya Levin 2019-01-17 23:59:20 +02:00 committed by David S. Miller
parent ce019faa70
commit b8c45a033a
1 changed files with 86 additions and 0 deletions
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86
Documentation/networking/devlink-health.txt Normal file
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The health mechanism is targeted for Real Time Alerting, in order to know when
something bad had 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.
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 and object dump procedures
- OOB initial parameters
Different parts of the driver can register different types of health reporters
with different handlers.
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 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
The 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
The devlink health interface (via netlink):
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.
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 | |
| +----------------------------> |
+--------+ +--------------------------+