diff options
| author | Tejun Heo <htejun@fb.com> | 2016-11-23 12:27:32 -0500 |
|---|---|---|
| committer | Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> | 2017-02-20 12:28:44 -0500 |
| commit | f08e9287200772c9a201d9f988dd78ffe2fc7ea4 (patch) | |
| tree | 02419720dbdfa49afac29335ce57ab2461914c3c /src | |
| parent | 2977724b09eb997fc84a80517447b5d4a70770c7 (diff) | |
core: keep supporting cgroup hybrid layout from v232 for live upgrades
v232's cgroup hybrid mode mounted v2 on /sys/fs/cgroup/systemd, which
unfortunately broke other tools which expect v1 there. From v233 on, hybrid
mode instead mounts and uses v2 on /sys/fs/cgroup/unified and keeps
/sys/fs/cgroup/systemd on v1 for compatibility with external tools. However,
to keep systemd live upgrades working, v233+ should be able to recognize v232
layout and keep using it.
This patch adds v232 hybrid mode support. If v232 layout is detected,
cg_unified(SYSTEMD_CGRouP_CONTROLLER) keeps returning %true but
cg_hybrid_unified() returns %false. This keeps process management on cgroup v2
but turns off the parallel layout.
Diffstat (limited to 'src')
| -rw-r--r-- | src/basic/cgroup-util.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c index 6601f16e01..9208873d9c 100644 --- a/src/basic/cgroup-util.c +++ b/src/basic/cgroup-util.c @@ -2283,6 +2283,20 @@ int cg_kernel_controllers(Set *controllers) { static thread_local CGroupUnified unified_cache = CGROUP_UNIFIED_UNKNOWN; +/* The hybrid mode was initially implemented in v232 and simply mounted + * cgroup v2 on /sys/fs/cgroup/systemd. This unfortunately broke other + * tools (such as docker) which expected the v1 "name=systemd" hierarchy + * on /sys/fs/cgroup/systemd. From v233 and on, the hybrid mode mountnbs + * v2 on /sys/fs/cgroup/unified and maintains "name=systemd" hierarchy + * on /sys/fs/cgroup/systemd for compatibility with other tools. + * + * To keep live upgrade working, we detect and support v232 layout. When + * v232 layout is detected, to keep cgroup v2 process management but + * disable the compat dual layout, we return %true on + * cg_unified(SYSTEMD_CGROUP_CONTROLLER) and %false on cg_hybrid_unified(). + */ +static thread_local bool unified_systemd_v232; + static int cg_update_unified(void) { struct statfs fs; @@ -2302,9 +2316,14 @@ static int cg_update_unified(void) { unified_cache = CGROUP_UNIFIED_ALL; else if (F_TYPE_EQUAL(fs.f_type, TMPFS_MAGIC)) { if (statfs("/sys/fs/cgroup/unified/", &fs) == 0 && - F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) + F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) { unified_cache = CGROUP_UNIFIED_SYSTEMD; - else { + unified_systemd_v232 = false; + } else if (statfs("/sys/fs/cgroup/systemd/", &fs) == 0 && + F_TYPE_EQUAL(fs.f_type, CGROUP2_SUPER_MAGIC)) { + unified_cache = CGROUP_UNIFIED_SYSTEMD; + unified_systemd_v232 = true; + } else { if (statfs("/sys/fs/cgroup/systemd/", &fs) < 0) return -errno; if (!F_TYPE_EQUAL(fs.f_type, CGROUP_SUPER_MAGIC)) @@ -2336,7 +2355,7 @@ bool cg_hybrid_unified(void) { assert(cg_update_unified() >= 0); - return unified_cache == CGROUP_UNIFIED_SYSTEMD; + return unified_cache == CGROUP_UNIFIED_SYSTEMD && !unified_systemd_v232; } int cg_unified_flush(void) { |