timers: use ref counts to count timers

RaisinTen · danielleadams · commit b5b375067886 · 2022-01-31T23:54:33.000-05:00
The additional objects that were getting added and deleted from the activeTimersMap object were slowing down the rest of the timers code, so this change falls back to using the ref counts to count the active timers inside process.getActiveResourcesInfo(). Fixes: #41219 Signed-off-by: Darshan Sen <darshan.sen@postman.com> PR-URL: #41231 Reviewed-By: Anatoli Papirovski <apapirovski@mac.com> Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
diff --git a/lib/internal/bootstrap/node.js b/lib/internal/bootstrap/node.js
@@ -39,17 +39,16 @@
 setupPrepareStackTrace();
 
 const {
+  Array,
   ArrayPrototypeConcat,
-  ArrayPrototypeFilter,
-  ArrayPrototypeMap,
+  ArrayPrototypeFill,
   FunctionPrototypeCall,
   JSONParse,
   ObjectDefineProperty,
   ObjectDefineProperties,
   ObjectGetPrototypeOf,
   ObjectPreventExtensions,
   ObjectSetPrototypeOf,
-  ObjectValues,
   ReflectGet,
   ReflectSet,
   SymbolToStringTag,
@@ -156,13 +155,12 @@ const rawMethods = internalBinding('process_methods');
   process._getActiveHandles = rawMethods._getActiveHandles;
 
   process.getActiveResourcesInfo = function() {
+    const timerCounts = internalTimers.getTimerCounts();
     return ArrayPrototypeConcat(
       rawMethods._getActiveRequestsInfo(),
       rawMethods._getActiveHandlesInfo(),
-      ArrayPrototypeMap(
-        ArrayPrototypeFilter(ObjectValues(internalTimers.activeTimersMap),
-                             ({ resource }) => resource.hasRef()),
-        ({ type }) => type));
+      ArrayPrototypeFill(new Array(timerCounts.timeoutCount), 'Timeout'),
+      ArrayPrototypeFill(new Array(timerCounts.immediateCount), 'Immediate'));
   };
 
   // TODO(joyeecheung): remove these
diff --git a/lib/internal/timers.js b/lib/internal/timers.js
@@ -139,12 +139,6 @@ const kRefed = Symbol('refed');
 // Create a single linked list instance only once at startup
 const immediateQueue = new ImmediateList();
 
-// Object map containing timers
-//
-// - key = asyncId
-// - value = { type, resource }
-const activeTimersMap = ObjectCreate(null);
-
 let nextExpiry = Infinity;
 let refCount = 0;
 
@@ -166,7 +160,6 @@ function initAsyncResource(resource, type) {
     resource[trigger_async_id_symbol] = getDefaultTriggerAsyncId();
   if (initHooksExist())
     emitInit(asyncId, type, triggerAsyncId, resource);
-  activeTimersMap[asyncId] = { type, resource };
 }
 
 // Timer constructor function.
@@ -478,7 +471,6 @@ function getTimerCallbacks(runNextTicks) {
 
         if (destroyHooksExist())
           emitDestroy(asyncId);
-        delete activeTimersMap[asyncId];
 
         outstandingQueue.head = immediate = immediate._idleNext;
       }
@@ -551,7 +543,6 @@ function getTimerCallbacks(runNextTicks) {
 
           if (destroyHooksExist())
             emitDestroy(asyncId);
-          delete activeTimersMap[asyncId];
         }
         continue;
       }
@@ -580,7 +571,6 @@ function getTimerCallbacks(runNextTicks) {
 
           if (destroyHooksExist())
             emitDestroy(asyncId);
-          delete activeTimersMap[asyncId];
         }
       }
 
@@ -648,6 +638,13 @@ class Immediate {
   }
 }
 
+function getTimerCounts() {
+  return {
+    timeoutCount: refCount,
+    immediateCount: immediateInfo[kRefCount],
+  };
+}
+
 module.exports = {
   TIMEOUT_MAX,
   kTimeout: Symbol('timeout'), // For hiding Timeouts on other internals.
@@ -670,9 +667,9 @@ module.exports = {
   active,
   unrefActive,
   insert,
-  activeTimersMap,
   timerListMap,
   timerListQueue,
   decRefCount,
-  incRefCount
+  incRefCount,
+  getTimerCounts,
 };
diff --git a/lib/timers.js b/lib/timers.js
@@ -45,7 +45,6 @@ const {
   kRefed,
   kHasPrimitive,
   getTimerDuration,
-  activeTimersMap,
   timerListMap,
   timerListQueue,
   immediateQueue,
@@ -88,7 +87,6 @@ function unenroll(item) {
   // Fewer checks may be possible, but these cover everything.
   if (destroyHooksExist() && item[async_id_symbol] !== undefined)
     emitDestroy(item[async_id_symbol]);
-  delete activeTimersMap[item[async_id_symbol]];
 
   L.remove(item);
 
@@ -331,7 +329,6 @@ function clearImmediate(immediate) {
   if (destroyHooksExist() && immediate[async_id_symbol] !== undefined) {
     emitDestroy(immediate[async_id_symbol]);
   }
-  delete activeTimersMap[immediate[async_id_symbol]];
 
   immediate._onImmediate = null;
 
