Hi Severin, 8239559/02 looks generally good . However I wonder about this :
I have a SLES15 aarch64 system with these settings : more /proc/cgroups #subsys_name hierarchy num_cgroups enabled cpuset 6 1 1 cpu 8 1 1 cpuacct 8 1 1 blkio 5 1 1 memory 9 1 1 devices 2 91 1 freezer 4 1 1 net_cls 3 1 1 perf_event 11 1 1 net_prio 3 1 1 hugetlb 10 1 1 pids 12 105 1 rdma 7 1 1 (so no hierarchy 0 ) However these information indicates the cgroup2 is supported : fgrep cgroup2 /proc/self/mountinfo 29 28 0:25 / /sys/fs/cgroup/unified rw,nosuid,nodev,noexec,relatime shared:5 - cgroup2 cgroup rw grep cgroup /proc/filesystems nodev cgroup nodev cgroup2 But the comment in http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8239559/02/webrev/src/java.base/linux/classes/jdk/internal/platform/CgroupSubsystemFactory.java.frames.html says 102 // For cgroups v2 all controllers need to have zero hierarchy id 103 // and /proc/self/mountinfo needs to have at least one cgroup filesystem 104 // mounted. Should this comment be adjusted ? On the system above we have no 0 in /proc/cgroups however it seems to me the system supports cgroug v2 ? Best regards, Matthias > > > I still need a *R*eviewer. Matthias, would you be willing to? > > Hi Severin, I can look into it tomorrow . > > Best regards, Matthias > > > > > > > On Mon, 2020-02-24 at 10:28 -0500, Bob Vandette wrote: > > > > > If you don’t have access to the information required to get metrics, I > > just assumed that > > > > > you would return NULL in CgroupSubsystemFactory.create() rather > > than making the > > > > > assumption that it works only to fail later. > > > > > > > > You are right. It makes little sense to continue in that case. Updated > > > > webrev: > > > > http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK- > > 8239559/02/webrev/ > > > > > > Looks good. > > > > Thanks for the review. > > > > I still need a *R*eviewer. Matthias, would you be willing to? > > > > Thanks, > > Severin > >
