diff options
| author | Michal Koutný <mkoutny@suse.com> | 2025-03-11 13:36:26 +0100 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2025-03-11 09:22:54 -1000 |
| commit | 78f6519ed0766e36f08954810ce05f19212242a6 (patch) | |
| tree | 7559944cc4873be0514aebc34ba596d75a1b54fa | |
| parent | fd4fd0a869e969a97753986b107729d4bb56525b (diff) | |
cgroup: Add deprecation message to legacy freezer controller
As explained in the commit 76f969e8948d8 ("cgroup: cgroup v2 freezer"),
the original freezer is imperfect, some users may unwittingly rely on it
when there exists the alternative of v2. Print a message when it happens
and explain that in the docs.
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
| -rw-r--r-- | Documentation/admin-guide/cgroup-v1/freezer-subsystem.rst | 4 | ||||
| -rw-r--r-- | kernel/cgroup/legacy_freezer.c | 6 |
2 files changed, 8 insertions, 2 deletions
diff --git a/Documentation/admin-guide/cgroup-v1/freezer-subsystem.rst b/Documentation/admin-guide/cgroup-v1/freezer-subsystem.rst index 582d3427de3f..a964aff373b1 100644 --- a/Documentation/admin-guide/cgroup-v1/freezer-subsystem.rst +++ b/Documentation/admin-guide/cgroup-v1/freezer-subsystem.rst @@ -125,3 +125,7 @@ to unfreeze all tasks in the container:: This is the basic mechanism which should do the right thing for user space task in a simple scenario. + +This freezer implementation is affected by shortcomings (see commit +76f969e8948d8 ("cgroup: cgroup v2 freezer")) and cgroup v2 freezer is +recommended. diff --git a/kernel/cgroup/legacy_freezer.c b/kernel/cgroup/legacy_freezer.c index 074653f964c1..039d1eb2f215 100644 --- a/kernel/cgroup/legacy_freezer.c +++ b/kernel/cgroup/legacy_freezer.c @@ -430,9 +430,11 @@ static ssize_t freezer_write(struct kernfs_open_file *of, if (strcmp(buf, freezer_state_strs(0)) == 0) freeze = false; - else if (strcmp(buf, freezer_state_strs(CGROUP_FROZEN)) == 0) + else if (strcmp(buf, freezer_state_strs(CGROUP_FROZEN)) == 0) { + pr_info_once("Freezing with imperfect legacy cgroup freezer. " + "See cgroup.freeze of cgroup v2\n"); freeze = true; - else + } else return -EINVAL; freezer_change_state(css_freezer(of_css(of)), freeze); |