[pve-devel] [PATCH common 2/2] cgroup: get mode by checking /sys/fs/cgroup mount point
Wolfgang Bumiller
w.bumiller at proxmox.com
Wed Sep 21 09:53:13 CEST 2022
Since even in pure unified layouts there may be a
`name=systemd` v1 cgroup mounted additionally (manually or
potentially via systemd-nspawn apparently), we should check
what's actually mounted at `/sys/fs/cgroup` rather than
whether v1 cgroups exist.
Signed-off-by: Wolfgang Bumiller <w.bumiller at proxmox.com>
---
src/PVE/CGroup.pm | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)
diff --git a/src/PVE/CGroup.pm b/src/PVE/CGroup.pm
index 92a0654..45c0788 100644
--- a/src/PVE/CGroup.pm
+++ b/src/PVE/CGroup.pm
@@ -86,21 +86,30 @@ sub get_cgroup_controllers() {
my $CGROUP_MODE = undef;
# Figure out which cgroup mode we're operating under:
#
-# Returns 1 if cgroupv1 controllers exist (hybrid or legacy mode), and 2 in a
-# cgroupv2-only environment.
+# For this we check the file system type of `/sys/fs/cgroup` as it may well be possible that some
+# additional cgroupv1 mount points have been created by tools such as `systemd-nspawn`, or
+# manually.
+#
+# Returns 1 for what we consider the hybrid layout, 2 for what we consider the unified layout.
#
# NOTE: To fully support a hybrid layout it is better to use functions like
-# `cpuset_controller_path`.
+# `cpuset_controller_path` and not rely on this value for anything involving paths.
#
# This is a function, not a method!
sub cgroup_mode() {
if (!defined($CGROUP_MODE)) {
- my ($v1, $v2) = get_cgroup_controllers();
- if (keys %$v1) {
- # hybrid or legacy mode
- $CGROUP_MODE = 1;
- } elsif ($v2) {
- $CGROUP_MODE = 2;
+ my $mounts = PVE::ProcFSTools::parse_proc_mounts();
+ for my $entry (@$mounts) {
+ my ($what, $dir, $fstype, $opts) = @$entry;
+ if ($dir eq '/sys/fs/cgroup') {
+ if ($fstype eq 'cgroup2') {
+ $CGROUP_MODE = 2;
+ last;
+ } else {
+ $CGROUP_MODE = 1;
+ last;
+ }
+ }
}
}
--
2.30.2
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