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# Default logging should provide enough data for typical investigation of "can't dump"/"can't restore"
# Default logging should provide enough data for typical investigation of "can't dump"/"can't restore"
# It should be possible to add developer-only debugging to see some more details
# It should be possible to add developer-only debugging to see some more details
# It should be possible to shut the logger up completely (maybe by specifying the log file as /dev/null)
== Binary logging ==
Let's try to implement the idea of putting log arguments in binary form into a buffer and flushing one at the end if necessary.
The majority of time spent in sprintf is in converting arguments to strings (e.g. %d). Next goes scanning the format string. At the end the string copying itself goes. If we manage to eliminat at least the first portion, that would be great.
== Log messages structuring ==
CRIU generates tons of messages. The most critical to troubleshooting is the pr_err-s. Need to introduce types of errors to make troubleshooting easier. E.g. we have the guide what to do [[when C/R fails]]. Need to introduce error types into it and print them before the error text. Suggested types of failures are:
* Restore errors
** Resource ID conflict (mostly valid for non-containers case)
*** PID mismatch
*** File with the name we need exists
*** [[CGroups]] exist (?)
** Missing item on restore
*** No [[TCP connection]] locks (for non netns case)
*** Missing session leader ([[CLI/opt/--shell-job]] might help)
*** Required file doesn't exist
* Dump errors
** [[What cannot be checkpointed|Unsupported object]]
*** [[AIO]] with events
*** Corked UDP socket
*** Tasks under strace
*** Knots in [[mount points]]
*** Too many of smth (open files) met
* Common errors
** Out of memory
** Access denied / permission denied
** Other unexpected/unhandled syscall error
** Error reading/writing [[images]]
** Proc file format error (do we really expect this thing?)
[[Category:Plans]]
[[Category:Thinkers]]