Tweak cgroup logic

CGroups.cpp

@@ -88,6 +88,10 @@ void CGroupCPU::SetShares(uint64_t val) {
     AppendUint64(_dir + CGROUP_CPU_SHARES_FILE, val);
 }
 
+bool CGroupCPU::HasCFSQuotaUS() {
+    return PathExists(_dir + CGROUP_CPU_PERIOD_US_FILE);
+}
+
 uint64_t CGroupCPU::GetCFSPeriodUS() {
     return ReadUint64(_dir + CGROUP_CPU_PERIOD_US_FILE);
 }

CGroups.h

@@ -37,6 +37,7 @@ public:
     uint64_t GetCFSPeriodUS();
     void SetCFSPeriodUS(uint64_t val);
 
+    bool HasCFSQuotaUS();
     uint64_t GetCFSQuotaUS();
     void SetCFSQuotaUS(uint64_t val);
 

CPULimits.cpp

@@ -50,7 +50,7 @@ std::shared_ptr<CGroupCPU> CPULimits::CGFromConfig(const Config& config, const s
 
     auto cg = CGroups::OpenCPU(cg_name);
 
-    if (hard_limit < MAX_PCT) {
+    if (hard_limit < MAX_PCT && cg->HasCFSQuotaUS()) {
         uint64_t period = cg->GetCFSPeriodUS();
         uint64_t quota = static_cast<uint64_t>(static_cast<double>(period)*(hard_limit/100));
         cg->SetCFSQuotaUS(quota);