diff --git a/libprocessgroup/cgroup_map.cpp b/libprocessgroup/cgroup_map.cpp index 9797d763f..20ae2be77 100644 --- a/libprocessgroup/cgroup_map.cpp +++ b/libprocessgroup/cgroup_map.cpp @@ -67,11 +67,14 @@ bool CgroupController::HasValue() const { return controller_ != nullptr; } -bool CgroupController::IsUsable() const { +bool CgroupController::IsUsable() { if (!HasValue()) return false; - static bool enabled = (access(GetProcsFilePath("", 0, 0).c_str(), F_OK) == 0); - return enabled; + if (state_ == UNKNOWN) { + state_ = access(GetProcsFilePath("", 0, 0).c_str(), F_OK) == 0 ? USABLE : MISSING; + } + + return state_ == USABLE; } std::string CgroupController::GetTasksFilePath(const std::string& rel_path) const { diff --git a/libprocessgroup/cgroup_map.h b/libprocessgroup/cgroup_map.h index 935041242..427d71b40 100644 --- a/libprocessgroup/cgroup_map.h +++ b/libprocessgroup/cgroup_map.h @@ -31,20 +31,28 @@ class CgroupController { public: // Does not own controller - explicit CgroupController(const ACgroupController* controller) : controller_(controller) {} + explicit CgroupController(const ACgroupController* controller) + : controller_(controller), state_(UNKNOWN) {} uint32_t version() const; const char* name() const; const char* path() const; bool HasValue() const; - bool IsUsable() const; + bool IsUsable(); std::string GetTasksFilePath(const std::string& path) const; std::string GetProcsFilePath(const std::string& path, uid_t uid, pid_t pid) const; bool GetTaskGroup(int tid, std::string* group) const; private: + enum ControllerState { + UNKNOWN = 0, + USABLE = 1, + MISSING = 2, + }; + const ACgroupController* controller_ = nullptr; + ControllerState state_; }; class CgroupMap {