> An issue similar to > [JDK-8239559](https://bugs.openjdk.java.net/browse/JDK-8239559) has been > discovered. On the > affected system, `/proc/self/mountinfo` contains a line such as this one: > > 35 26 0:26 / /sys/fs/cgroup/systemd rw,nosuid,nodev,noexec,relatime - cgroup > systemd rw,name=systemd > > > Note that `/proc/cgroups` looks like this: > > #subsys_name hierarchy num_cgroups enabled > cpuset 0 1 1 > cpu 0 1 1 > cpuacct 0 1 1 > blkio 0 1 1 > memory 0 1 1 > devices 0 1 1 > freezer 0 1 1 > net_cls 0 1 1 > perf_event 0 1 1 > net_prio 0 1 1 > hugetlb 0 1 1 > pids 0 1 1 > > This is in fact a cgroups v1 system with systemd put into a separate > namespace via FS type `cgroup`. That mountinfo > line confuses the cgroups version detection heuristic. It only looked whether > or not there is **any** entry in > mountinfo of FS-type `cgroup` . That's wrong. A better heuristic would be > looking at controllers we care about: `cpu`, > `cpuacct`, `memory`, `cpuset` for hotspot and some more for the Java side. > The proposed fix on the hotspot side is to > set `any_cgroup_mounts_found` to true only if one of those controllers show > up in mountinfo. Otherwise, we know it's > cgroup v2 due to the zero hierarchy ids. For the Java side the proposal is > to add some parsing for mountinfo lines and > look for `cgroup` FS-type lines which aren't also mounted purely for systemd. > **Testing** > > - [x] Linux x86_64 container tests on cgroup v1 (fastdebug) > - [x] Linux x86_64 container tests on cgroup v2 (fastdebug) > - [x] Added regression test which fails prior the patch and passes after > - [x] Submit testing
Severin Gehwolf has updated the pull request incrementally with one additional commit since the last revision: 8245543: Cgroups: Incorrect detection logic on some systems (still reproducible) ------------- Changes: - all: https://git.openjdk.java.net/jdk/pull/485/files - new: https://git.openjdk.java.net/jdk/pull/485/files/d334ac60..5e2ca2dc Webrevs: - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=485&range=03 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=485&range=02-03 Stats: 548 lines in 5 files changed: 284 ins; 193 del; 71 mod Patch: https://git.openjdk.java.net/jdk/pull/485.diff Fetch: git fetch https://git.openjdk.java.net/jdk pull/485/head:pull/485 PR: https://git.openjdk.java.net/jdk/pull/485
