Explicitly document EBUSY returned by writing into cgroup.procs if controllers are enabled; and writing into cgroup.subtree_control if there are attached processes.
The return code might be slightly surprising, and because there is nothing obviously better, let's document it at least. Signed-off-by: Roman Gushchin <[email protected]> Cc: Tejun Heo <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] --- Documentation/cgroup-v2.txt | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt index 74cdeaed9f7a..57302f88a4ad 100644 --- a/Documentation/cgroup-v2.txt +++ b/Documentation/cgroup-v2.txt @@ -799,6 +799,9 @@ All cgroup core files are prefixed with "cgroup." When delegating a sub-hierarchy, write access to this file should be granted along with the containing directory. + If the target cgroup has enabled controllers, writing to this + file will fail with EBUSY. + In a threaded cgroup, reading this file fails with EOPNOTSUPP as all the processes belong to the thread root. Writing is supported and moves every thread of the process to the cgroup. @@ -850,6 +853,9 @@ All cgroup core files are prefixed with "cgroup." the last one is effective. When multiple enable and disable operations are specified, either all succeed or all fail. + If the cgroup has attached tasks, writing to this file will + fail with EBUSY. + cgroup.events A read-only flat-keyed file which exists on non-root cgroups. The following entries are defined. Unless specified -- 2.14.3
