This is an automated email from the ASF dual-hosted git repository.
bmahler pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mesos.git
The following commit(s) were added to refs/heads/master by this push:
new 78143cbf0 [cgroups2] Add mounting and unmounting of cgroup2 filesystem.
78143cbf0 is described below
commit 78143cbf015cff9478714addf2634bf87a6b57c0
Author: Devin Leamy <[email protected]>
AuthorDate: Tue Feb 27 15:41:11 2024 -0500
[cgroups2] Add mounting and unmounting of cgroup2 filesystem.
Introduces:
- `cgroups2::mount()`: Mount the cgroup2 hierarchy.
- `cgroups2::mounted()`: Check if the cgroup2 hierarchy is mounted
at /sys/fs/cgroup.
- `cgroups2::unmount()`: Unmount the cgroup2 hierarchy from /sys/fs/cgroup.
The root mount point for the cgroup2 file system is hard-coded to be
/sys/fs/cgroup,
which is the default mount point on most systems.
Review: https://reviews.apache.org/r/74872/
---
src/linux/cgroups2.cpp | 89 +++++++++++++++++++++++++++++++++++++++++++++++++-
src/linux/cgroups2.hpp | 18 +++++++++-
2 files changed, 105 insertions(+), 2 deletions(-)
diff --git a/src/linux/cgroups2.cpp b/src/linux/cgroups2.cpp
index baa13557e..b42a012bc 100644
--- a/src/linux/cgroups2.cpp
+++ b/src/linux/cgroups2.cpp
@@ -16,22 +16,109 @@
#include <string>
+#include <stout/os.hpp>
+#include <stout/path.hpp>
#include <stout/try.hpp>
#include "linux/cgroups2.hpp"
#include "linux/fs.hpp"
using std::string;
+using mesos::internal::fs::MountTable;
namespace cgroups2 {
-// Name of the cgroupv2 filesystem as found in /proc/filesystems.
+// Name of the cgroups v2 filesystem as found in /proc/filesystems.
const string FILE_SYSTEM = "cgroup2";
+// Mount point for the cgroups2 file system.
+const string MOUNT_POINT = "/sys/fs/cgroup";
+
+
bool enabled()
{
Try<bool> supported = mesos::internal::fs::supported(cgroups2::FILE_SYSTEM);
return supported.isSome() && *supported;
}
+
+Try<Nothing> mount()
+{
+ if (!cgroups2::enabled()) {
+ return Error("cgroups2 is not enabled");
+ }
+
+ Try<bool> mounted = cgroups2::mounted();
+ if (mounted.isError()) {
+ return Error("Failed to check if cgroups2 filesystem is mounted: "
+ + mounted.error());
+ }
+ if (*mounted) {
+ return Error("cgroup2 filesystem is already mounted at"
+ " '" + cgroups2::MOUNT_POINT + "'");
+ }
+
+ Try<Nothing> mkdir = os::mkdir(cgroups2::MOUNT_POINT);
+ if (mkdir.isError()) {
+ return Error("Failed to create cgroups2 directory"
+ " '" + cgroups2::MOUNT_POINT + "'"
+ ": " + mkdir.error());
+ }
+
+ return mesos::internal::fs::mount(
+ None(),
+ cgroups2::MOUNT_POINT,
+ cgroups2::FILE_SYSTEM,
+ 0,
+ None());
+}
+
+
+Try<bool> mounted()
+{
+ Try<MountTable> mountTable = MountTable::read("/proc/mounts");
+ if (mountTable.isError()) {
+ return Error("Failed to read /proc/mounts: " + mountTable.error());
+ }
+
+ foreach (MountTable::Entry entry, mountTable.get().entries) {
+ if (entry.type == cgroups2::FILE_SYSTEM) {
+ if (entry.dir == MOUNT_POINT) {
+ return true;
+ }
+ return Error("Found cgroups2 mount at an unexpected location"
+ " '" + entry.dir + "'");
+ }
+ }
+
+ return false;
+}
+
+
+Try<Nothing> unmount()
+{
+ Try<bool> mounted = cgroups2::mounted();
+ if (mounted.isError()) {
+ return Error("Failed to check if the cgroup2 filesystem is mounted: "
+ + mounted.error());
+ }
+
+ if (!*mounted) {
+ return Error("cgroups2 filesystem is not mounted");
+ }
+
+ Try<Nothing> result = mesos::internal::fs::unmount(MOUNT_POINT);
+ if (result.isError()) {
+ return Error("Failed to unmount the cgroup2 hierarchy" +
+ " '" + cgroups2::MOUNT_POINT + "': " + result.error());
+ }
+
+ Try<Nothing> rmdir = os::rmdir(cgroups2::MOUNT_POINT);
+ if (rmdir.isError()) {
+ return Error(
+ "Failed to remove directory '" + cgroups2::MOUNT_POINT + "': " +
+ rmdir.error());
+ }
+}
+
} // namespace cgroups2
diff --git a/src/linux/cgroups2.hpp b/src/linux/cgroups2.hpp
index 833960d30..0c54e464b 100644
--- a/src/linux/cgroups2.hpp
+++ b/src/linux/cgroups2.hpp
@@ -17,11 +17,27 @@
#ifndef __CGROUPS_V2_HPP__
#define __CGROUPS_V2_HPP__
+#include <stout/nothing.hpp>
+#include <stout/try.hpp>
+
namespace cgroups2 {
// Checks if cgroups2 is available on the system.
bool enabled();
+// Mounts the cgroups2 file system at /sys/fs/cgroup. Errors if
+// the cgroups v2 file system is already mounted.
+Try<Nothing> mount();
+
+// Checks if the cgroup2 file systems is mounted at /sys/fs/cgroup,
+// returns an error if the mount is found at an unexpected location.
+Try<bool> mounted();
+
+// Unmounts the cgroups2 file system from /sys/fs/cgroup. Errors if
+// the cgroup2 file system is not mounted at /sys/fs/cgroup. It's the
+// responsibility of the caller to ensure all child cgroups have been
destroyed.
+Try<Nothing> unmount();
+
} // namespace cgroups2
-#endif // __CGROUPS_V2_HPP__
\ No newline at end of file
+#endif // __CGROUPS_V2_HPP__
