lib: rewrite AsyncLocalStorage without async_hooks

PR-URL: https://github.com/nodejs/node/pull/48528
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Yagiz Nizipli <yagiz@nizipli.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Rafael Gonzaga <rafael.nunu@hotmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Gerhard Stöbich <deb2001-github@yahoo.de>

benchmark/async_hooks/async-local-storage-getstore-nested-resources.js

@@ -38,9 +38,11 @@ function runInAsyncScopes(resourceCount, cb, i = 0) {
 
 function main({ n, resourceCount }) {
   const store = new AsyncLocalStorage();
+  store.run({}, () => {
     runInAsyncScopes(resourceCount, () => {
       bench.start();
       runBenchmark(store, n);
       bench.end(n);
     });
+  });
 }

benchmark/async_hooks/async-local-storage-getstore-nested-run.js

@@ -14,7 +14,7 @@ const { AsyncLocalStorage } = require('async_hooks');
  *        - AsyncLocalStorage1.getStore()
  */
 const bench = common.createBenchmark(main, {
-  sotrageCount: [1, 10, 100],
+  storageCount: [1, 10, 100],
   n: [1e4],
 });
 
@@ -34,8 +34,8 @@ function runStores(stores, value, cb, idx = 0) {
   }
 }
 
-function main({ n, sotrageCount }) {
-  const stores = new Array(sotrageCount).fill(0).map(() => new AsyncLocalStorage());
+function main({ n, storageCount }) {
+  const stores = new Array(storageCount).fill(0).map(() => new AsyncLocalStorage());
   const contextValue = {};
 
   runStores(stores, contextValue, () => {

doc/api/cli.md

@@ -886,6 +886,21 @@ and `"` are usable.
 It is possible to run code containing inline types by passing
 [`--experimental-strip-types`][].
 
+### `--experimental-async-context-frame`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+> Stability: 1 - Experimental
+
+Enables the use of AsyncLocalStorage backed by AsyncContextFrame rather than
+the default implementation which relies on async\_hooks. This new model is
+implemented very differently and so could have differences in how context data
+flows within the application. As such, it is presently recommended to be sure
+your application behaviour is unaffected by this change before using it in
+production.
+
 ### `--experimental-default-type=type`
 
 <!-- YAML
@@ -2893,6 +2908,7 @@ one is included in the list below.
 * `--enable-network-family-autoselection`
 * `--enable-source-maps`
 * `--experimental-abortcontroller`
+* `--experimental-async-context-frame`
 * `--experimental-default-type`
 * `--experimental-detect-module`
 * `--experimental-eventsource`

lib/async_hooks.js

@@ -10,7 +10,6 @@ const {
   NumberIsSafeInteger,
   ObjectDefineProperties,
   ObjectFreeze,
-  ObjectIs,
   ReflectApply,
   Symbol,
 } = primordials;
@@ -30,6 +29,8 @@ const {
 } = require('internal/validators');
 const internal_async_hooks = require('internal/async_hooks');
 
+const AsyncContextFrame = require('internal/async_context_frame');
+
 // Get functions
 // For userland AsyncResources, make sure to emit a destroy event when the
 // resource gets gced.
@@ -158,6 +159,7 @@ function createHook(fns) {
 // Embedder API //
 
 const destroyedSymbol = Symbol('destroyed');
+const contextFrameSymbol = Symbol('context_frame');
 
 class AsyncResource {
   constructor(type, opts = kEmptyObject) {
@@ -177,6 +179,8 @@ class AsyncResource {
       throw new ERR_INVALID_ASYNC_ID('triggerAsyncId', triggerAsyncId);
     }
 
+    this[contextFrameSymbol] = AsyncContextFrame.current();
+
     const asyncId = newAsyncId();
     this[async_id_symbol] = asyncId;
     this[trigger_async_id_symbol] = triggerAsyncId;
@@ -201,12 +205,12 @@ class AsyncResource {
     const asyncId = this[async_id_symbol];
     emitBefore(asyncId, this[trigger_async_id_symbol], this);
 
+    const contextFrame = this[contextFrameSymbol];
+    const prior = AsyncContextFrame.exchange(contextFrame);
     try {
-      const ret =
-        ReflectApply(fn, thisArg, args);
-
-      return ret;
+      return ReflectApply(fn, thisArg, args);
     } finally {
+      AsyncContextFrame.set(prior);
       if (hasAsyncIdStack())
         emitAfter(asyncId);
     }
@@ -270,110 +274,15 @@ class AsyncResource {
   }
 }
 
-const storageList = [];
-const storageHook = createHook({
-  init(asyncId, type, triggerAsyncId, resource) {
-    const currentResource = executionAsyncResource();
-    // Value of currentResource is always a non null object
-    for (let i = 0; i < storageList.length; ++i) {
-      storageList[i]._propagate(resource, currentResource, type);
-    }
-  },
-});
-
-class AsyncLocalStorage {
-  constructor() {
-    this.kResourceStore = Symbol('kResourceStore');
-    this.enabled = false;
-  }
-
-  static bind(fn) {
-    return AsyncResource.bind(fn);
-  }
-
-  static snapshot() {
-    return AsyncLocalStorage.bind((cb, ...args) => cb(...args));
-  }
-
-  disable() {
-    if (this.enabled) {
-      this.enabled = false;
-      // If this.enabled, the instance must be in storageList
-      ArrayPrototypeSplice(storageList,
-                           ArrayPrototypeIndexOf(storageList, this), 1);
-      if (storageList.length === 0) {
-        storageHook.disable();
-      }
-    }
-  }
-
-  _enable() {
-    if (!this.enabled) {
-      this.enabled = true;
-      ArrayPrototypePush(storageList, this);
-      storageHook.enable();
-    }
-  }
-
-  // Propagate the context from a parent resource to a child one
-  _propagate(resource, triggerResource, type) {
-    const store = triggerResource[this.kResourceStore];
-    if (this.enabled) {
-      resource[this.kResourceStore] = store;
-    }
-  }
-
-  enterWith(store) {
-    this._enable();
-    const resource = executionAsyncResource();
-    resource[this.kResourceStore] = store;
-  }
-
-  run(store, callback, ...args) {
-    // Avoid creation of an AsyncResource if store is already active
-    if (ObjectIs(store, this.getStore())) {
-      return ReflectApply(callback, null, args);
-    }
-
-    this._enable();
-
-    const resource = executionAsyncResource();
-    const oldStore = resource[this.kResourceStore];
-
-    resource[this.kResourceStore] = store;
-
-    try {
-      return ReflectApply(callback, null, args);
-    } finally {
-      resource[this.kResourceStore] = oldStore;
-    }
-  }
-
-  exit(callback, ...args) {
-    if (!this.enabled) {
-      return ReflectApply(callback, null, args);
-    }
-    this.disable();
-    try {
-      return ReflectApply(callback, null, args);
-    } finally {
-      this._enable();
-    }
-  }
-
-  getStore() {
-    if (this.enabled) {
-      const resource = executionAsyncResource();
-      return resource[this.kResourceStore];
-    }
-  }
-}
-
 // Placing all exports down here because the exported classes won't export
 // otherwise.
 module.exports = {
   // Public API
-  AsyncLocalStorage,
+  get AsyncLocalStorage() {
+    return AsyncContextFrame.enabled ?
+      require('internal/async_local_storage/native') :
+      require('internal/async_local_storage/async_hooks');
+  },
   createHook,
   executionAsyncId,
   triggerAsyncId,

lib/internal/async_context_frame.js

@@ -0,0 +1,50 @@
+'use strict';
+
+const {
+  getContinuationPreservedEmbedderData,
+  setContinuationPreservedEmbedderData,
+} = internalBinding('async_context_frame');
+
+let enabled_;
+
+class AsyncContextFrame extends Map {
+  constructor(store, data) {
+    super(AsyncContextFrame.current());
+    this.set(store, data);
+  }
+
+  static get enabled() {
+    enabled_ ??= require('internal/options')
+      .getOptionValue('--experimental-async-context-frame');
+    return enabled_;
+  }
+
+  static current() {
+    if (this.enabled) {
+      return getContinuationPreservedEmbedderData();
+    }
+  }
+
+  static set(frame) {
+    if (this.enabled) {
+      setContinuationPreservedEmbedderData(frame);
+    }
+  }
+
+  static exchange(frame) {
+    const prior = this.current();
+    this.set(frame);
+    return prior;
+  }
+
+  static disable(store) {
+    const frame = this.current();
+    frame?.disable(store);
+  }
+
+  disable(store) {
+    this.delete(store);
+  }
+}
+
+module.exports = AsyncContextFrame;

lib/internal/async_local_storage/async_hooks.js

@@ -0,0 +1,117 @@
+'use strict';
+
+const {
+  ArrayPrototypeIndexOf,
+  ArrayPrototypePush,
+  ArrayPrototypeSplice,
+  ObjectIs,
+  ReflectApply,
+  Symbol,
+} = primordials;
+
+const {
+  AsyncResource,
+  createHook,
+  executionAsyncResource,
+} = require('async_hooks');
+
+const storageList = [];
+const storageHook = createHook({
+  init(asyncId, type, triggerAsyncId, resource) {
+    const currentResource = executionAsyncResource();
+    // Value of currentResource is always a non null object
+    for (let i = 0; i < storageList.length; ++i) {
+      storageList[i]._propagate(resource, currentResource, type);
+    }
+  },
+});
+
+class AsyncLocalStorage {
+  constructor() {
+    this.kResourceStore = Symbol('kResourceStore');
+    this.enabled = false;
+  }
+
+  static bind(fn) {
+    return AsyncResource.bind(fn);
+  }
+
+  static snapshot() {
+    return AsyncLocalStorage.bind((cb, ...args) => cb(...args));
+  }
+
+  disable() {
+    if (this.enabled) {
+      this.enabled = false;
+      // If this.enabled, the instance must be in storageList
+      const index = ArrayPrototypeIndexOf(storageList, this);
+      ArrayPrototypeSplice(storageList, index, 1);
+      if (storageList.length === 0) {
+        storageHook.disable();
+      }
+    }
+  }
+
+  _enable() {
+    if (!this.enabled) {
+      this.enabled = true;
+      ArrayPrototypePush(storageList, this);
+      storageHook.enable();
+    }
+  }
+
+  // Propagate the context from a parent resource to a child one
+  _propagate(resource, triggerResource, type) {
+    const store = triggerResource[this.kResourceStore];
+    if (this.enabled) {
+      resource[this.kResourceStore] = store;
+    }
+  }
+
+  enterWith(store) {
+    this._enable();
+    const resource = executionAsyncResource();
+    resource[this.kResourceStore] = store;
+  }
+
+  run(store, callback, ...args) {
+    // Avoid creation of an AsyncResource if store is already active
+    if (ObjectIs(store, this.getStore())) {
+      return ReflectApply(callback, null, args);
+    }
+
+    this._enable();
+
+    const resource = executionAsyncResource();
+    const oldStore = resource[this.kResourceStore];
+
+    resource[this.kResourceStore] = store;
+
+    try {
+      return ReflectApply(callback, null, args);
+    } finally {
+      resource[this.kResourceStore] = oldStore;
+    }
+  }
+
+  exit(callback, ...args) {
+    if (!this.enabled) {
+      return ReflectApply(callback, null, args);
+    }
+    this.disable();
+    try {
+      return ReflectApply(callback, null, args);
+    } finally {
+      this._enable();
+    }
+  }
+
+  getStore() {
+    if (this.enabled) {
+      const resource = executionAsyncResource();
+      return resource[this.kResourceStore];
+    }
+  }
+}
+
+module.exports = AsyncLocalStorage;

lib/internal/async_local_storage/native.js

@@ -0,0 +1,47 @@
+'use strict';
+
+const {
+  ReflectApply,
+} = primordials;
+
+const AsyncContextFrame = require('internal/async_context_frame');
+const { AsyncResource } = require('async_hooks');
+
+class AsyncLocalStorage {
+  static bind(fn) {
+    return AsyncResource.bind(fn);
+  }
+
+  static snapshot() {
+    return AsyncLocalStorage.bind((cb, ...args) => cb(...args));
+  }
+
+  disable() {
+    AsyncContextFrame.disable(this);
+  }
+
+  enterWith(data) {
+    const frame = new AsyncContextFrame(this, data);
+    AsyncContextFrame.set(frame);
+  }
+
+  run(data, fn, ...args) {
+    const prior = AsyncContextFrame.current();
+    this.enterWith(data);
+    try {
+      return ReflectApply(fn, null, args);
+    } finally {
+      AsyncContextFrame.set(prior);
+    }
+  }
+
+  exit(fn, ...args) {
+    return this.run(undefined, fn, ...args);
+  }
+
+  getStore() {
+    return AsyncContextFrame.current()?.get(this);
+  }
+}
+
+module.exports = AsyncLocalStorage;

lib/internal/process/promises.js

@@ -38,6 +38,8 @@ const {
 } = require('internal/async_hooks');
 const { isErrorStackTraceLimitWritable } = require('internal/errors');
 
+const AsyncContextFrame = require('internal/async_context_frame');
+
 // *Must* match Environment::TickInfo::Fields in src/env.h.
 const kHasRejectionToWarn = 1;
 
@@ -260,6 +262,7 @@ function unhandledRejection(promise, reason) {
     uid: ++lastPromiseId,
     warned: false,
     domain: process.domain,
+    contextFrame: AsyncContextFrame.current(),
   });
   setHasRejectionToWarn(true);
 }
@@ -466,9 +469,12 @@ function processPromiseRejections() {
       );
     }
 
+    const { contextFrame } = promiseInfo;
+    const priorContextFrame = AsyncContextFrame.exchange(contextFrame);
     try {
       needPop = unhandledRejectionsMode(promise, promiseInfo, promiseAsyncId);
     } finally {
+      AsyncContextFrame.set(priorContextFrame);
       needPop &&
       promiseAsyncId !== undefined &&
       popAsyncContext(promiseAsyncId);

lib/internal/process/task_queues.js

@@ -3,6 +3,7 @@
 const {
   Array,
   FunctionPrototypeBind,
+  Symbol,
 } = primordials;
 
 const {
@@ -41,6 +42,10 @@ const {
 
 const { AsyncResource } = require('async_hooks');
 
+const AsyncContextFrame = require('internal/async_context_frame');
+
+const async_context_frame = Symbol('asyncContextFrame');
+
 // *Must* match Environment::TickInfo::Fields in src/env.h.
 const kHasTickScheduled = 0;
 
@@ -68,6 +73,9 @@ function processTicksAndRejections() {
   let tock;
   do {
     while ((tock = queue.shift()) !== null) {
+      const priorContextFrame =
+        AsyncContextFrame.exchange(tock[async_context_frame]);
+
       const asyncId = tock[async_id_symbol];
       emitBefore(asyncId, tock[trigger_async_id_symbol], tock);
 
@@ -91,6 +99,8 @@ function processTicksAndRejections() {
       }
 
       emitAfter(asyncId);
+
+      AsyncContextFrame.set(priorContextFrame);
     }
     runMicrotasks();
   } while (!queue.isEmpty() || processPromiseRejections());
@@ -125,6 +135,7 @@ function nextTick(callback) {
   const tickObject = {
     [async_id_symbol]: asyncId,
     [trigger_async_id_symbol]: triggerAsyncId,
+    [async_context_frame]: AsyncContextFrame.current(),
     callback,
     args,
   };

lib/internal/timers.js

@@ -122,6 +122,10 @@ let debug = require('internal/util/debuglog').debuglog('timer', (fn) => {
   debug = fn;
 });
 
+const AsyncContextFrame = require('internal/async_context_frame');
+
+const async_context_frame = Symbol('asyncContextFrame');
+
 // *Must* match Environment::ImmediateInfo::Fields in src/env.h.
 const kCount = 0;
 const kRefCount = 1;
@@ -162,6 +166,7 @@ function initAsyncResource(resource, type) {
   const asyncId = resource[async_id_symbol] = newAsyncId();
   const triggerAsyncId =
     resource[trigger_async_id_symbol] = getDefaultTriggerAsyncId();
+  resource[async_context_frame] = AsyncContextFrame.current();
   if (initHooksExist())
     emitInit(asyncId, type, triggerAsyncId, resource);
 }
@@ -494,6 +499,9 @@ function getTimerCallbacks(runNextTicks) {
 
       prevImmediate = immediate;
 
+      const priorContextFrame =
+        AsyncContextFrame.exchange(immediate[async_context_frame]);
+
       const asyncId = immediate[async_id_symbol];
       emitBefore(asyncId, immediate[trigger_async_id_symbol], immediate);
 
@@ -513,6 +521,8 @@ function getTimerCallbacks(runNextTicks) {
       }
 
       emitAfter(asyncId);
+
+      AsyncContextFrame.set(priorContextFrame);
     }
 
     if (queue === outstandingQueue)
@@ -587,6 +597,9 @@ function getTimerCallbacks(runNextTicks) {
         continue;
       }
 
+      const priorContextFrame =
+        AsyncContextFrame.exchange(timer[async_context_frame]);
+
       emitBefore(asyncId, timer[trigger_async_id_symbol], timer);
 
       let start;
@@ -620,6 +633,8 @@ function getTimerCallbacks(runNextTicks) {
       }
 
       emitAfter(asyncId);
+
+      AsyncContextFrame.set(priorContextFrame);
     }
 
     // If `L.peek(list)` returned nothing, the list was either empty or we have

node.gyp

@@ -68,6 +68,7 @@
       'src/api/exceptions.cc',
       'src/api/hooks.cc',
       'src/api/utils.cc',
+      'src/async_context_frame.cc',
       'src/async_wrap.cc',
       'src/base_object.cc',
       'src/cares_wrap.cc',
@@ -185,6 +186,7 @@
       'src/aliased_buffer-inl.h',
       'src/aliased_struct.h',
       'src/aliased_struct-inl.h',
+      'src/async_context_frame.h',
       'src/async_wrap.h',
       'src/async_wrap-inl.h',
       'src/base_object.h',

src/api/async_resource.cc

@@ -1,5 +1,6 @@
-#include "node.h"
+#include "async_context_frame.h"
 #include "env-inl.h"
+#include "node.h"
 
 namespace node {
 
@@ -18,36 +19,55 @@ AsyncResource::AsyncResource(Isolate* isolate,
     : env_(Environment::GetCurrent(isolate)),
       resource_(isolate, resource) {
   CHECK_NOT_NULL(env_);
-  async_context_ = EmitAsyncInit(isolate, resource, name,
-                                 trigger_async_id);
+  env_->SetAsyncResourceContextFrame(
+      reinterpret_cast<std::uintptr_t>(this),
+      {isolate, async_context_frame::current(isolate)});
+  async_context_ = EmitAsyncInit(isolate, resource, name, trigger_async_id);
 }
 
 AsyncResource::~AsyncResource() {
+  CHECK_NOT_NULL(env_);
+  env_->RemoveAsyncResourceContextFrame(reinterpret_cast<std::uintptr_t>(this));
   EmitAsyncDestroy(env_, async_context_);
 }
 
 MaybeLocal<Value> AsyncResource::MakeCallback(Local<Function> callback,
                                               int argc,
                                               Local<Value>* argv) {
-  return node::MakeCallback(env_->isolate(), get_resource(),
-                            callback, argc, argv,
-                            async_context_);
+  auto isolate = env_->isolate();
+  auto context_frame =
+      env_->GetAsyncResourceContextFrame(reinterpret_cast<std::uintptr_t>(this))
+          .Get(isolate);
+  async_context_frame::Scope async_context_frame_scope(isolate, context_frame);
+
+  return node::MakeCallback(
+      isolate, get_resource(), callback, argc, argv, async_context_);
 }
 
 MaybeLocal<Value> AsyncResource::MakeCallback(const char* method,
                                               int argc,
                                               Local<Value>* argv) {
-  return node::MakeCallback(env_->isolate(), get_resource(),
-                            method, argc, argv,
-                            async_context_);
+  auto isolate = env_->isolate();
+  auto context_frame =
+      env_->GetAsyncResourceContextFrame(reinterpret_cast<std::uintptr_t>(this))
+          .Get(isolate);
+  async_context_frame::Scope async_context_frame_scope(isolate, context_frame);
+
+  return node::MakeCallback(
+      isolate, get_resource(), method, argc, argv, async_context_);
 }
 
 MaybeLocal<Value> AsyncResource::MakeCallback(Local<String> symbol,
                                               int argc,
                                               Local<Value>* argv) {
-  return node::MakeCallback(env_->isolate(), get_resource(),
-                            symbol, argc, argv,
-                            async_context_);
+  auto isolate = env_->isolate();
+  auto context_frame =
+      env_->GetAsyncResourceContextFrame(reinterpret_cast<std::uintptr_t>(this))
+          .Get(isolate);
+  async_context_frame::Scope async_context_frame_scope(isolate, context_frame);
+
+  return node::MakeCallback(
+      isolate, get_resource(), symbol, argc, argv, async_context_);
 }
 
 Local<Object> AsyncResource::get_resource() {

src/api/callback.cc

@@ -1,6 +1,7 @@
-#include "node.h"
+#include "async_context_frame.h"
 #include "async_wrap-inl.h"
 #include "env-inl.h"
+#include "node.h"
 #include "v8.h"
 
 namespace node {
@@ -14,6 +15,7 @@ using v8::Local;
 using v8::MaybeLocal;
 using v8::Object;
 using v8::String;
+using v8::Undefined;
 using v8::Value;
 
 CallbackScope::CallbackScope(Isolate* isolate,
@@ -38,16 +40,18 @@ CallbackScope::~CallbackScope() {
 }
 
 InternalCallbackScope::InternalCallbackScope(AsyncWrap* async_wrap, int flags)
-    : InternalCallbackScope(async_wrap->env(),
+    : InternalCallbackScope(
+          async_wrap->env(),
           async_wrap->object(),
-                            { async_wrap->get_async_id(),
-                              async_wrap->get_trigger_async_id() },
-                            flags) {}
+          {async_wrap->get_async_id(), async_wrap->get_trigger_async_id()},
+          flags,
+          async_wrap->context_frame()) {}
 
 InternalCallbackScope::InternalCallbackScope(Environment* env,
                                              Local<Object> object,
                                              const async_context& asyncContext,
-                                             int flags)
+                                             int flags,
+                                             v8::Local<v8::Value> context_frame)
     : env_(env),
       async_context_(asyncContext),
       object_(object),
@@ -76,6 +80,9 @@ InternalCallbackScope::InternalCallbackScope(Environment* env,
 
   isolate->SetIdle(false);
 
+  prior_context_frame_.Reset(
+      isolate, async_context_frame::exchange(isolate, context_frame));
+
   env->async_hooks()->push_async_context(
     async_context_.async_id, async_context_.trigger_async_id, object);
 
@@ -117,9 +124,12 @@ void InternalCallbackScope::Close() {
     AsyncWrap::EmitAfter(env_, async_context_.async_id);
   }
 
-  if (pushed_ids_)
+  if (pushed_ids_) {
     env_->async_hooks()->pop_async_context(async_context_.async_id);
 
+    async_context_frame::exchange(isolate, prior_context_frame_.Get(isolate));
+  }
+
   if (failed_) return;
 
   if (env_->async_callback_scope_depth() > 1 || skip_task_queues_) {
@@ -173,7 +183,8 @@ MaybeLocal<Value> InternalMakeCallback(Environment* env,
                                        const Local<Function> callback,
                                        int argc,
                                        Local<Value> argv[],
-                                       async_context asyncContext) {
+                                       async_context asyncContext,
+                                       Local<Value> context_frame) {
   CHECK(!recv.IsEmpty());
 #ifdef DEBUG
   for (int i = 0; i < argc; i++)
@@ -194,7 +205,8 @@ MaybeLocal<Value> InternalMakeCallback(Environment* env,
         async_hooks->fields()[AsyncHooks::kUsesExecutionAsyncResource] > 0;
   }
 
-  InternalCallbackScope scope(env, resource, asyncContext, flags);
+  InternalCallbackScope scope(
+      env, resource, asyncContext, flags, context_frame);
   if (scope.Failed()) {
     return MaybeLocal<Value>();
   }
@@ -270,6 +282,17 @@ MaybeLocal<Value> MakeCallback(Isolate* isolate,
                                int argc,
                                Local<Value> argv[],
                                async_context asyncContext) {
+  return InternalMakeCallback(
+      isolate, recv, callback, argc, argv, asyncContext, Undefined(isolate));
+}
+
+MaybeLocal<Value> InternalMakeCallback(Isolate* isolate,
+                                       Local<Object> recv,
+                                       Local<Function> callback,
+                                       int argc,
+                                       Local<Value> argv[],
+                                       async_context asyncContext,
+                                       Local<Value> context_frame) {
   // Observe the following two subtleties:
   //
   // 1. The environment is retrieved from the callback function's context.
@@ -281,8 +304,8 @@ MaybeLocal<Value> MakeCallback(Isolate* isolate,
       Environment::GetCurrent(callback->GetCreationContextChecked());
   CHECK_NOT_NULL(env);
   Context::Scope context_scope(env->context());
-  MaybeLocal<Value> ret =
-      InternalMakeCallback(env, recv, recv, callback, argc, argv, asyncContext);
+  MaybeLocal<Value> ret = InternalMakeCallback(
+      env, recv, recv, callback, argc, argv, asyncContext, context_frame);
   if (ret.IsEmpty() && env->async_callback_scope_depth() == 0) {
     // This is only for legacy compatibility and we may want to look into
     // removing/adjusting it.
@@ -315,9 +338,14 @@ MaybeLocal<Value> MakeSyncCallback(Isolate* isolate,
 
   // This is a toplevel invocation and the caller (intentionally)
   // didn't provide any async_context to run in. Install a default context.
-  MaybeLocal<Value> ret =
-    InternalMakeCallback(env, env->process_object(), recv, callback, argc, argv,
-                         async_context{0, 0});
+  MaybeLocal<Value> ret = InternalMakeCallback(env,
+                                               env->process_object(),
+                                               recv,
+                                               callback,
+                                               argc,
+                                               argv,
+                                               async_context{0, 0},
+                                               v8::Undefined(isolate));
   return ret;
 }
 

src/async_context_frame.cc

@@ -0,0 +1,89 @@
+#include "async_context_frame.h"  // NOLINT(build/include_inline)
+
+#include "env-inl.h"
+#include "node_errors.h"
+#include "node_external_reference.h"
+#include "tracing/traced_value.h"
+#include "util-inl.h"
+
+#include "debug_utils-inl.h"
+
+#include "v8.h"
+
+using v8::Context;
+using v8::Isolate;
+using v8::Local;
+using v8::Object;
+using v8::String;
+using v8::Value;
+
+namespace node {
+namespace async_context_frame {
+
+//
+// Scope helper
+//
+Scope::Scope(Isolate* isolate, Local<Value> object) : isolate_(isolate) {
+  auto prior = exchange(isolate, object);
+  prior_.Reset(isolate, prior);
+}
+
+Scope::~Scope() {
+  auto value = prior_.Get(isolate_);
+  set(isolate_, value);
+}
+
+Local<Value> current(Isolate* isolate) {
+  return isolate->GetContinuationPreservedEmbedderData();
+}
+
+void set(Isolate* isolate, Local<Value> value) {
+  auto env = Environment::GetCurrent(isolate);
+  if (!env->options()->async_context_frame) {
+    return;
+  }
+
+  isolate->SetContinuationPreservedEmbedderData(value);
+}
+
+// NOTE: It's generally recommended to use async_context_frame::Scope
+// but sometimes (such as enterWith) a direct exchange is needed.
+Local<Value> exchange(Isolate* isolate, Local<Value> value) {
+  auto prior = current(isolate);
+  set(isolate, value);
+  return prior;
+}
+
+void CreatePerContextProperties(Local<Object> target,
+                                Local<Value> unused,
+                                Local<Context> context,
+                                void* priv) {
+  Environment* env = Environment::GetCurrent(context);
+
+  Local<String> getContinuationPreservedEmbedderData = FIXED_ONE_BYTE_STRING(
+      env->isolate(), "getContinuationPreservedEmbedderData");
+  Local<String> setContinuationPreservedEmbedderData = FIXED_ONE_BYTE_STRING(
+      env->isolate(), "setContinuationPreservedEmbedderData");
+
+  // Grab the intrinsics from the binding object and expose those to our
+  // binding layer.
+  Local<Object> binding = context->GetExtrasBindingObject();
+  target
+      ->Set(context,
+            getContinuationPreservedEmbedderData,
+            binding->Get(context, getContinuationPreservedEmbedderData)
+                .ToLocalChecked())
+      .Check();
+  target
+      ->Set(context,
+            setContinuationPreservedEmbedderData,
+            binding->Get(context, setContinuationPreservedEmbedderData)
+                .ToLocalChecked())
+      .Check();
+}
+
+}  // namespace async_context_frame
+}  // namespace node
+
+NODE_BINDING_CONTEXT_AWARE_INTERNAL(
+    async_context_frame, node::async_context_frame::CreatePerContextProperties)

src/async_context_frame.h

@@ -0,0 +1,33 @@
+#ifndef SRC_ASYNC_CONTEXT_FRAME_H_
+#define SRC_ASYNC_CONTEXT_FRAME_H_
+
+#if defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#include "base_object.h"
+#include "v8.h"
+
+#include <cstdint>
+
+namespace node {
+namespace async_context_frame {
+
+class Scope {
+ public:
+  explicit Scope(v8::Isolate* isolate, v8::Local<v8::Value> object);
+  ~Scope();
+
+ private:
+  v8::Isolate* isolate_;
+  v8::Global<v8::Value> prior_;
+};
+
+v8::Local<v8::Value> current(v8::Isolate* isolate);
+void set(v8::Isolate* isolate, v8::Local<v8::Value> value);
+v8::Local<v8::Value> exchange(v8::Isolate* isolate, v8::Local<v8::Value> value);
+
+}  // namespace async_context_frame
+}  // namespace node
+
+#endif  // defined(NODE_WANT_INTERNALS) && NODE_WANT_INTERNALS
+
+#endif  // SRC_ASYNC_CONTEXT_FRAME_H_

src/async_wrap-inl.h

@@ -49,6 +49,9 @@ inline double AsyncWrap::get_trigger_async_id() const {
   return trigger_async_id_;
 }
 
+inline v8::Local<v8::Value> AsyncWrap::context_frame() const {
+  return context_frame_.Get(env()->isolate());
+}
 
 inline v8::MaybeLocal<v8::Value> AsyncWrap::MakeCallback(
     const v8::Local<v8::String> symbol,

src/async_wrap.cc

@@ -20,6 +20,7 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include "async_wrap.h"  // NOLINT(build/include_inline)
+#include "async_context_frame.h"
 #include "async_wrap-inl.h"
 #include "env-inl.h"
 #include "node_errors.h"
@@ -513,8 +514,9 @@ AsyncWrap::AsyncWrap(Environment* env,
 }
 
 AsyncWrap::AsyncWrap(Environment* env, Local<Object> object)
-  : BaseObject(env, object) {
-}
+    : BaseObject(env, object),
+      context_frame_(env->isolate(),
+                     async_context_frame::current(env->isolate())) {}
 
 // This method is necessary to work around one specific problem:
 // Before the init() hook runs, if there is one, the BaseObject() constructor
@@ -606,8 +608,9 @@ void AsyncWrap::AsyncReset(Local<Object> resource, double execution_async_id,
                                                      : execution_async_id;
   trigger_async_id_ = env()->get_default_trigger_async_id();
 
+  Isolate* isolate = env()->isolate();
   {
-    HandleScope handle_scope(env()->isolate());
+    HandleScope handle_scope(isolate);
     Local<Object> obj = object();
     CHECK(!obj.IsEmpty());
     if (resource != obj) {
@@ -637,6 +640,8 @@ void AsyncWrap::AsyncReset(Local<Object> resource, double execution_async_id,
       UNREACHABLE();
   }
 
+  context_frame_.Reset(isolate, async_context_frame::current(isolate));
+
   if (silent) return;
 
   EmitAsyncInit(env(), resource,
@@ -680,8 +685,15 @@ MaybeLocal<Value> AsyncWrap::MakeCallback(const Local<Function> cb,
 
   ProviderType provider = provider_type();
   async_context context { get_async_id(), get_trigger_async_id() };
-  MaybeLocal<Value> ret = InternalMakeCallback(
-      env(), object(), object(), cb, argc, argv, context);
+  MaybeLocal<Value> ret =
+      InternalMakeCallback(env(),
+                           object(),
+                           object(),
+                           cb,
+                           argc,
+                           argv,
+                           context,
+                           context_frame_.Get(env()->isolate()));
 
   // This is a static call with cached values because the `this` object may
   // no longer be alive at this point.

src/async_wrap.h

@@ -187,6 +187,8 @@ class AsyncWrap : public BaseObject {
   inline double get_async_id() const;
   inline double get_trigger_async_id() const;
 
+  inline v8::Local<v8::Value> context_frame() const;
+
   void AsyncReset(v8::Local<v8::Object> resource,
                   double execution_async_id = kInvalidAsyncId,
                   bool silent = false);
@@ -239,6 +241,8 @@ class AsyncWrap : public BaseObject {
   // Because the values may be Reset(), cannot be made const.
   double async_id_ = kInvalidAsyncId;
   double trigger_async_id_ = kInvalidAsyncId;
+
+  v8::Global<v8::Value> context_frame_;
 };
 
 }  // namespace node

src/env-inl.h

@@ -934,6 +934,26 @@ inline void Environment::RemoveHeapSnapshotNearHeapLimitCallback(
                                         heap_limit);
 }
 
+inline void Environment::SetAsyncResourceContextFrame(
+    std::uintptr_t async_resource_handle,
+    v8::Global<v8::Value>&& context_frame) {
+  async_resource_context_frames_.emplace(
+      std::make_pair(async_resource_handle, std::move(context_frame)));
+}
+
+inline const v8::Global<v8::Value>& Environment::GetAsyncResourceContextFrame(
+    std::uintptr_t async_resource_handle) {
+  auto&& async_resource_context_frame =
+      async_resource_context_frames_.find(async_resource_handle);
+  CHECK_NE(async_resource_context_frame, async_resource_context_frames_.end());
+
+  return async_resource_context_frame->second;
+}
+
+inline void Environment::RemoveAsyncResourceContextFrame(
+    std::uintptr_t async_resource_handle) {
+  async_resource_context_frames_.erase(async_resource_handle);
+}
 }  // namespace node
 
 // These two files depend on each other. Including base_object-inl.h after this

src/env.h

@@ -596,7 +596,7 @@ v8::Maybe<ExitCode> EmitProcessExitInternal(Environment* env);
  * environment. Each environment has a principal realm. An environment can
  * create multiple subsidiary synthetic realms.
  */
-class Environment : public MemoryRetainer {
+class Environment final : public MemoryRetainer {
  public:
   Environment(const Environment&) = delete;
   Environment& operator=(const Environment&) = delete;
@@ -1059,6 +1059,14 @@ class Environment : public MemoryRetainer {
 
   v8::Global<v8::Module> temporary_required_module_facade_original;
 
+  void SetAsyncResourceContextFrame(std::uintptr_t async_resource_handle,
+                                    v8::Global<v8::Value>&&);
+
+  const v8::Global<v8::Value>& GetAsyncResourceContextFrame(
+      std::uintptr_t async_resource_handle);
+
+  void RemoveAsyncResourceContextFrame(std::uintptr_t async_resource_handle);
+
  private:
   inline void ThrowError(v8::Local<v8::Value> (*fun)(v8::Local<v8::String>,
                                                      v8::Local<v8::Value>),
@@ -1231,6 +1239,9 @@ class Environment : public MemoryRetainer {
   // track of the BackingStore for a given pointer.
   std::unordered_map<char*, std::unique_ptr<v8::BackingStore>>
       released_allocated_buffers_;
+
+  std::unordered_map<std::uintptr_t, v8::Global<v8::Value>>
+      async_resource_context_frames_;
 };
 
 }  // namespace node

src/node_api.cc

@@ -1,3 +1,4 @@
+#include "async_context_frame.h"
 #include "async_wrap-inl.h"
 #include "env-inl.h"
 #define NAPI_EXPERIMENTAL
@@ -545,7 +546,9 @@ class AsyncContext {
       : env_(env) {
     async_id_ = node_env()->new_async_id();
     trigger_async_id_ = node_env()->get_default_trigger_async_id();
-    resource_.Reset(node_env()->isolate(), resource_object);
+    v8::Isolate* isolate = node_env()->isolate();
+    resource_.Reset(isolate, resource_object);
+    context_frame_.Reset(isolate, node::async_context_frame::current(isolate));
     lost_reference_ = false;
     if (externally_managed_resource) {
       resource_.SetWeak(
@@ -571,13 +574,15 @@ class AsyncContext {
       int argc,
       v8::Local<v8::Value> argv[]) {
     EnsureReference();
-    return node::InternalMakeCallback(node_env(),
+    return node::InternalMakeCallback(
+        node_env(),
         resource(),
         recv,
         callback,
         argc,
         argv,
-                                      {async_id_, trigger_async_id_});
+        {async_id_, trigger_async_id_},
+        context_frame_.Get(node_env()->isolate()));
   }
 
   inline napi_callback_scope OpenCallbackScope() {
@@ -633,6 +638,7 @@ class AsyncContext {
   double trigger_async_id_;
   v8::Global<v8::Object> resource_;
   bool lost_reference_;
+  v8::Global<v8::Value> context_frame_;
 };
 
 }  // end of anonymous namespace

src/node_binding.cc

@@ -29,6 +29,7 @@
 // The binding IDs that start with 'internal_only' are not exposed to the user
 // land even from internal/test/binding module under --expose-internals.
 #define NODE_BUILTIN_STANDARD_BINDINGS(V)                                      \
+  V(async_context_frame)                                                       \
   V(async_wrap)                                                                \
   V(blob)                                                                      \
   V(block_list)                                                                \

src/node_internals.h

@@ -212,7 +212,17 @@ v8::MaybeLocal<v8::Value> InternalMakeCallback(
     const v8::Local<v8::Function> callback,
     int argc,
     v8::Local<v8::Value> argv[],
-    async_context asyncContext);
+    async_context asyncContext,
+    v8::Local<v8::Value> context_frame);
+
+v8::MaybeLocal<v8::Value> InternalMakeCallback(
+    v8::Isolate* isolate,
+    v8::Local<v8::Object> recv,
+    const v8::Local<v8::Function> callback,
+    int argc,
+    v8::Local<v8::Value> argv[],
+    async_context asyncContext,
+    v8::Local<v8::Value> context_frame);
 
 v8::MaybeLocal<v8::Value> MakeSyncCallback(v8::Isolate* isolate,
                                            v8::Local<v8::Object> recv,
@@ -232,10 +242,13 @@ class InternalCallbackScope {
     // compatibility issues, but it shouldn't.)
     kSkipTaskQueues = 2
   };
-  InternalCallbackScope(Environment* env,
+  InternalCallbackScope(
+      Environment* env,
       v8::Local<v8::Object> object,
       const async_context& asyncContext,
-                        int flags = kNoFlags);
+      int flags = kNoFlags,
+      v8::Local<v8::Value> context_frame = v8::Local<v8::Value>());
+
   // Utility that can be used by AsyncWrap classes.
   explicit InternalCallbackScope(AsyncWrap* async_wrap, int flags = 0);
   ~InternalCallbackScope();
@@ -253,6 +266,7 @@ class InternalCallbackScope {
   bool failed_ = false;
   bool pushed_ids_ = false;
   bool closed_ = false;
+  v8::Global<v8::Value> prior_context_frame_;
 };
 
 class DebugSealHandleScope {

src/node_options.cc

@@ -487,6 +487,10 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption(
       "--experimental-wasi-unstable-preview1", "", NoOp{}, kAllowedInEnvvar);
   AddOption("--expose-gc", "expose gc extension", V8Option{}, kAllowedInEnvvar);
+  AddOption("--experimental-async-context-frame",
+            "Improve AsyncLocalStorage performance with AsyncContextFrame",
+            &EnvironmentOptions::async_context_frame,
+            kAllowedInEnvvar);
   AddOption("--expose-internals", "", &EnvironmentOptions::expose_internals);
   AddOption("--frozen-intrinsics",
             "experimental frozen intrinsics support",

src/node_options.h

@@ -136,6 +136,7 @@ class EnvironmentOptions : public Options {
   bool allow_worker_threads = false;
   bool experimental_repl_await = true;
   bool experimental_vm_modules = false;
+  bool async_context_frame = false;
   bool expose_internals = false;
   bool force_node_api_uncaught_exceptions_policy = false;
   bool frozen_intrinsics = false;

test/fixtures/errors/async_error_nexttick_main.snapshot

@@ -1,7 +1,7 @@
 Error: test
     at one (*fixtures*async-error.js:4:9)
     at two (*fixtures*async-error.js:17:9)
-    at process.processTicksAndRejections (node:internal*process*task_queues:95:5)
+    at process.processTicksAndRejections (node:internal*process*task_queues:105:5)
     at async three (*fixtures*async-error.js:20:3)
     at async four (*fixtures*async-error.js:24:3)
     at async main (*async_error_nexttick_main.js:7:5)

test/parallel/test-async-context-frame.mjs

@@ -0,0 +1,59 @@
+import { isWindows } from '../common/index.mjs';
+import { spawn } from 'node:child_process';
+import { once } from 'node:events';
+import { opendir } from 'node:fs/promises';
+import { fileURLToPath } from 'node:url';
+import { describe, it } from 'node:test';
+import { sep } from 'node:path';
+
+const python = process.env.PYTHON || (isWindows ? 'python' : 'python3');
+
+const testRunner = fileURLToPath(
+  new URL('../../tools/test.py', import.meta.url)
+);
+
+const setNames = ['async-hooks', 'parallel'];
+
+// Get all test names for each set
+const testSets = await Promise.all(setNames.map(async (name) => {
+  const path = fileURLToPath(new URL(`../${name}`, import.meta.url));
+  const dir = await opendir(path);
+
+  const tests = [];
+  for await (const entry of dir) {
+    if (entry.name.startsWith('test-async-local-storage-')) {
+      tests.push(entry.name);
+    }
+  }
+
+  return {
+    name,
+    tests
+  };
+}));
+
+// Merge test sets with set name prefix
+const tests = testSets.reduce((m, v) => {
+  for (const test of v.tests) {
+    m.push(`${v.name}${sep}${test}`);
+  }
+  return m;
+}, []);
+
+describe('AsyncContextFrame', {
+  concurrency: tests.length
+}, () => {
+  for (const test of tests) {
+    it(test, async () => {
+      const proc = spawn(python, [
+        testRunner,
+        '--node-args=--experimental-async-context-frame',
+        test,
+      ], {
+        stdio: ['ignore', 'ignore', 'inherit'],
+      });
+
+      await once(proc, 'exit');
+    });
+  }
+});

test/parallel/test-async-local-storage-exit-does-not-leak.js

@@ -5,20 +5,23 @@ const { AsyncLocalStorage } = require('async_hooks');
 
 const als = new AsyncLocalStorage();
 
-// Make sure _propagate function exists.
-assert.ok(typeof als._propagate === 'function');
-
-// The als instance should be getting removed from the storageList in
-// lib/async_hooks.js when exit(...) is called, therefore when the nested runs
-// are called there should be no copy of the als in the storageList to run the
-// _propagate method on.
-als._propagate = common.mustNotCall('_propagate() should not be called');
+// The _propagate function only exists on the old JavaScript implementation.
+if (typeof als._propagate === 'function') {
+  // The als instance should be getting removed from the storageList in
+  // lib/async_hooks.js when exit(...) is called, therefore when the nested runs
+  // are called there should be no copy of the als in the storageList to run the
+  // _propagate method on.
+  als._propagate = common.mustNotCall('_propagate() should not be called');
+}
 
 const done = common.mustCall();
 
+const data = true;
+
 function run(count) {
   if (count === 0) return done();
-  als.run({}, () => {
+  assert.notStrictEqual(als.getStore(), data);
+  als.run(data, () => {
     als.exit(run, --count);
   });
 }

test/parallel/test-bootstrap-modules.js

@@ -30,6 +30,8 @@ expected.beforePreExec = new Set([
   'NativeModule internal/errors',
   'Internal Binding config',
   'Internal Binding timers',
+  'Internal Binding async_context_frame',
+  'NativeModule internal/async_context_frame',
   'Internal Binding async_wrap',
   'Internal Binding task_queue',
   'Internal Binding symbols',