[systemd-devel] Suggestion on StartLimitAction=

Allmeroth, Robert robert.allmeroth at harman.com
Fri Feb 1 06:22:49 PST 2013


On embedded systems it is sometimes not very useful to call shutdown scripts 
or reboot(2) in case of a watchdog failure / failed service (re)starting,
e.g. FS/Flash corruption, FS driver failure, special HW init failure

- Typically important file systems are read-only on embedded systems so it would
  not harm the system to do a hard reset.
- The processor on which systemd is running on is not necessarily the PowerController, a call
  to reboot(2) would only stop/reboot that node. But other nodes like FPGA, ASIC, DSP also
  need a reset.

Does it make sense to you to have a StartLimitAction= where the systemd stops sending 
heartbeats to the kernel? (e.g. StartLimitAction = StopKernelHeartbeat <optional reason>)
In this case the watchdog on the PowerController is able to react very fast accordingly.

Of course this will only work if the kernel watchdog module is already connected to the PowerController.
If not - the only escape is the 'expect watchdog register timer' of the PowerController. 
In general we would like to avoid running into the expect timer because we have no hint why the system 
did not respond.

Best regards

Harman Automotive Division

Becker-Göring-Straße 16
76307 Karlsbad
Phone: +49 (0) 7248-71-1156
Fax: +49 (0) 7248-71-2156
Email: Robert.Allmeroth at harman.com
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