Freeze fixes and v1 kludges #2545
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Commit 9fae23f grossly (by 1000x) miscalculated the number of attempts required, as a result, we are seeing something like this: > (00.000340) freezing processes: 100000 attempts with 100 ms steps > (00.000351) freezer.state=THAWED > (00.000358) freezer.state=FREEZING > (00.100446) freezer.state=FREEZING > ...close to 100 lines skipped... > (09.915110) freezer.state=FREEZING > (10.000432) Error (criu/cr-dump.c:1467): Timeout reached. Try to interrupt: 0 > (10.000563) freezer.state=FREEZING For 10s with 100ms steps we only need 100 attempts, not 100000. While at it, add an error print in case we hit the timeout earlier than i reaches nr_attempts. Signed-off-by: Kir Kolyshkin <[email protected]>
Cgroup v1 freezer has always been problematic, failing to freeze a cgroup. In runc, we have implemented a few kludges to increase the chance of succeeding, but those are used when runc freezes a cgroup for its own purposes (for "runc pause" and to modify device properties for cgroup v1). When criu is used, it fails to freeze a cgroup from time to time (see [1], [2]). Let's try adding kludges similar to ones in runc. Alas, I have absolutely no way to test this, so please review carefully. [1]: opencontainers/runc#4273 [2]: opencontainers/runc#4457 Signed-off-by: Kir Kolyshkin <[email protected]>
This was referenced Dec 13, 2024
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1. freeze_processes: fix nr_attempts calculation
Commit 9fae23f grossly (by 1000x) miscalculated the number
of attempts required, as a result, we are seeing something like this:
For 10s with 100ms steps we only need 100 attempts, not 100000.
While at it, add an error print in case we hit the timeout earlier than
i reaches nr_attempts.
2. freeze_processes: implement kludges for cgroup v1
Cgroup v1 freezer has always been problematic, failing to freeze a
cgroup.
In runc, we have implemented a few kludges to increase the chance of
succeeding, but those are used when runc freezes a cgroup for its own
purposes (for "runc pause" and to modify device properties for cgroup
v1).
When criu is used, it fails to freeze a cgroup from time to time
(see 1, 2). Let's try adding kludges similar to ones in runc.
Alas, I have absolutely no way to test this, so please review carefully.