cf-natali commented on a change in pull request #355: Handle EBUSY when
destroying a cgroup.
URL: https://github.com/apache/mesos/pull/355#discussion_r401705020
##########
File path: src/linux/cgroups.cpp
##########
@@ -696,13 +696,24 @@ Try<Nothing> remove(const string& hierarchy, const
string& cgroup)
string path = path::join(hierarchy, cgroup);
// Do NOT recursively remove cgroups.
- Try<Nothing> rmdir = os::rmdir(path, false);
- if (rmdir.isError()) {
- return Error(
+ // TODO The retry was added as a fix for kernel bug
+ // https://lkml.org/lkml/2020/1/15/1349
+ // where calling rmdir on a seemingly empty cgroup can fail
+ // with EBUSY while some tasks are exiting.
+ auto delay = Milliseconds(1);
+ for (auto retry = 10; ;) {
+ Try<Nothing> rmdir = os::rmdir(path, false);
+ if (!rmdir.isError()) {
+ return rmdir;
+ } else if (retry > 0) {
+ os::sleep(delay);
Review comment:
There is at least another code path which calls `cgroup::remove` - when the
freezer subsystem isn't available:
https://github.com/apache/mesos/blob/f8a3dd334934094ec44e07fa350f958d218bc78f/src/linux/cgroups.cpp#L1596
Also it seems that `cgroup::mount` has a similar hack:
https://github.com/apache/mesos/blob/f8a3dd334934094ec44e07fa350f958d218bc78f/src/linux/cgroups.cpp#L575
It returns a future but can block retrying?
So unless you feel strongly about it maybe best to keep it there, since
failing to remove a cgroup is pretty much a fatal error?
Also do you have a suggestion for this - I agree we should check for EBUSY,
I'm not sure how to do it :).
> > Should we retry only if ::rmdir() returns EBUSY errno error?
>
> Definitely - I wanted to do that but I'm not sure what's the best way to
do it: is there a way to access errno from Try<Nothing> rmdir or can I just
assume that the global errno is preserved and access it directly?
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
With regards,
Apache Git Services
