commit fa7a05fe5f7a166baefb07298b4908ebc9b90075
author Suren Baghdasaryan <surenb@google.com> Wed May 08 17:59:55 2019 -0700
committer Suren Baghdasaryan <surenb@google.com> Tue May 21 10:03:21 2019 -0700
tree f2c98c45fa117e7857a3ad85a65ee92488f33f50
parent 7dc7c3a9c66cc5f934e57a57415dae33c4830841

libprocessgroup: add flags to indicate when a controller failed to mount

Controllers listed in cgroups.json file might fail to mount if kernel is
not configured to support them. We need a way to indicate whether a
controller was successfully mounted and is usable to avoid logging errors
and warnings when a controller that failed to mount is being used. Add
flags bitmask to cgrouprc controller descriptor and use a bit to indicate
that controller is successfully mounted. Modify cpusets_enabled() and
schedboost_enabled() functions to use this bit and report the actual
availability of the controller.

Bug: 124080437
Test: libcutils_test with cpuset and schedtune controllers disabled
Change-Id: I770cc39fe50465146e3205aacf77dc3c56923c5d
Signed-off-by: Suren Baghdasaryan <surenb@google.com>

libprocessgroup/cgroup_map.cpp

diff --git a/libprocessgroup/cgroup_map.cpp b/libprocessgroup/cgroup_map.cpp
index 6cd6b6e..92fcd1e 100644
--- a/libprocessgroup/cgroup_map.cpp
+++ b/libprocessgroup/cgroup_map.cpp
@@ -67,6 +67,13 @@
     return controller_ != nullptr;
 }
 
+bool CgroupController::IsUsable() const {
+    if (!HasValue()) return false;
+
+    uint32_t flags = ACgroupController_getFlags(controller_);
+    return (flags & CGROUPRC_CONTROLLER_FLAG_MOUNTED) != 0;
+}
+
 std::string CgroupController::GetTasksFilePath(const std::string& rel_path) const {
     std::string tasks_path = path();
 
@@ -153,6 +160,7 @@
         const ACgroupController* controller = ACgroupFile_getController(i);
         LOG(INFO) << "\t" << ACgroupController_getName(controller) << " ver "
                   << ACgroupController_getVersion(controller) << " path "
+                  << ACgroupController_getFlags(controller) << " flags "
                   << ACgroupController_getPath(controller);
     }
 }