- separate out busyLock from Cluster's idleLock

src/kernel/KernelProcessor.cc

@@ -43,8 +43,8 @@ inline void KernelProcessor::idleLoop(bool irqs) {
     if (cluster.setProcessorIdle(*this, terminate)) {
       stats->idle.count();
       if (!CurrFM().zeroMemory<smallpl>()) halt(!irqs);
-      cluster.setProcessorBusy(*this);
     }
+    cluster.setProcessorBusy(*this);
   }
   unreachable();
 }

src/libfibre/SystemProcessor.cc

@@ -101,8 +101,8 @@ inline void SystemProcessor::idleLoop() {
     if (reinterpret_cast<FibreCluster&>(cluster).setProcessorIdle(*this, terminate)) {
       stats->idle.count();
       idleSem.P();
-      cluster.setProcessorBusy(*this);
     }
+    cluster.setProcessorBusy(*this);
   }
 }
 

src/runtime/Cluster.h

@@ -33,6 +33,7 @@ protected:
   SystemLock       idleLock;
   ProcessorList    idleList;
   volatile size_t  idleCount;
+  SystemLock       busyLock;
   ProcessorList    busyList;
 
 public:
@@ -54,7 +55,7 @@ public:
       ProcessorRing::insert_after(*ringProc, proc);
     }
 #endif
-    ScopedLock<SystemLock> sli(idleLock);
+    ScopedLock<SystemLock> sli(busyLock);
     busyList.push_back(proc);
     pCount += 1;
   }
@@ -69,7 +70,7 @@ public:
     if (ringProc == &proc) ringProc = nullptr;
     ProcessorRing::remove(proc);
 #endif
-    ScopedLock<SystemLock> sli(idleLock);
+    ScopedLock<SystemLock> sli(busyLock);
     busyList.remove(proc);
     pCount -= 1;
   }
@@ -92,7 +93,7 @@ public:
   }
 
   StackContext* steal() {
-    ScopedLock<SystemLock> sl(idleLock);
+    ScopedLock<SystemLock> sl(busyLock);
     BaseProcessor* p = busyList.front();
     while (p != busyList.edge()) {
       StackContext* s = p->dequeue<true>(_friend<Cluster>());
@@ -107,21 +108,25 @@ public:
   }
 
   size_t setProcessorIdle(BaseProcessor& proc, bool terminating) {
-    ScopedLock<SystemLock> sl(idleLock);
-    if (!terminating && (backgroundProc.load() || stagingProc.load())) return 0;
+    busyLock.acquire();
     busyList.remove(proc);
+    busyLock.release();
+    Runtime::debugS("Processor ", FmtHex(&proc), " on idle list");
+    ScopedLock<SystemLock> sl(idleLock);
     idleList.push_back(proc);
     idleCount += 1;
-    Runtime::debugS("Processor ", FmtHex(&proc), " on idle list");
+    if (!terminating && (backgroundProc.load() || stagingProc.load())) return 0;
     return idleCount;
   }
 
   void setProcessorBusy(BaseProcessor& proc) {
-    ScopedLock<SystemLock> sl(idleLock);
+    idleLock.acquire();
     idleCount -= 1;
     idleList.remove(proc);
-    busyList.push_back(proc);
+    idleLock.release();
     Runtime::debugS("Processor ", FmtHex(&proc), " off idle list");
+    ScopedLock<SystemLock> sl(busyLock);
+    busyList.push_back(proc);
   }
 
   BaseProcessor* findIdleProcessorHard() {